Improve BaseUInt:

This commit reworks the BaseUInt class, which was originally taken from
Bitcoin and has since been heavily modified.

The internal limb type now widens from 32 to 64 bits when the requested
width is a multiple of 64. This halves the iteration count when working
on limbs; coupled with the use of add-with-carry intrinsics, the result
is better code generation and optimized use of processor resources.

The constructors have been reshuffled, constraining how an instance can
be initialized. As a result, many common initialization errors will now
fail at compile time instead of run time.

A `BaseUInt` can now be initialized with:

 - A byte sequence of fixed size, i.e an `std::array`, a C array, or a
   fixed-extent `std::span` of `unsigned char` or `std::byte`.
 - A string literal, formatted as a hexadecimal string with no leading
   0x. Malformed or improperly sized inputs are a compile-time error.
 - An unsigned integer. This constructor is mostly used for tests, and
   must execute at compile time.
 - A byte sequence whose length is not known at compile time, via the
   fromRaw() function which returns a seated `std::optional` only if
   the input is byte sequence is properly sized.

The runtime raw-pointer and `std::uint64_t` constructors are gone, as
are the container assignment operator and the the `fromVoid` and
`fromVoidChecked` functions.

Other changes:

 - The SFINAE-based container trait is replaced by the ByteCopySource
   and FixedByteRange concepts.
 - operator== and operator<=> are now hidden friends. The workaround
   in the old operator<=> is gone.
 - Efficient tag conversion is now possible.
 - `BaseUInt` is now `noexcept` and (almost) fully `constexpr`: every
   operation except byte access, hashing and text output is usable in
   constant evaluation.

Cleanups:

 - Most invocations of `stringIsUInt256Sized` in PeerImp are now gone
   and leverage `fromRaw`.

API-CHANGELOG.md

@@ -30,6 +30,11 @@ Version 3.5.0 is not yet released.
 
 - `subscribe`, `unsubscribe`: Added an optional `mpt_issuances` request field, an array of MPT issuance IDs (hex strings). Subscribers receive a message with `type` `mptTransaction` for each validated transaction whose metadata affects a subscribed issuance; the message has the same fields as the `transactions` stream. MPT issuance subscriptions count toward the per-connection subscription limit. An empty array, a non-array value, or an invalid ID returns `invalidParams`. ([#5671](https://github.com/XRPLF/rippled/pull/5671))
 
+### Bugfixes in 3.5.0
+
+- `channel_authorize`: The `channel_id` field now returns an `invalidParams` error if the value is not a string. [#7582](https://github.com/XRPLF/rippled/pull/7582)
+- `channel_verify`: The `channel_id` and `signature` fields now return an `invalidParams` error if the value is not a string. [#7582](https://github.com/XRPLF/rippled/pull/7582)
+
 ## XRP Ledger server version 3.4.0
 
 Version 3.4.0 is not yet released. These changes are available in the 3.4.0 beta releases.

cmake/scripts/codegen/templates/LedgerEntryTests.cpp.mako

@@ -31,7 +31,7 @@ namespace xrpl::ledger_entries {
 // builder's STObject and the wrapper's SLE.
 TEST(${name}Tests, BuilderSettersRoundTrip)
 {
-    UInt256 const index{1u};
+    constexpr UInt256 index{1};
 
 % for field in fields:
     auto const ${field["paramName"]}Value = ${canonical_expr(field)};
@@ -85,7 +85,7 @@ TEST(${name}Tests, BuilderSettersRoundTrip)
 // from that SLE, build a new wrapper, and verify all fields (and validate()).
 TEST(${name}Tests, BuilderFromSleRoundTrip)
 {
-    UInt256 const index{2u};
+    constexpr UInt256 index{2};
 
 % for field in fields:
     auto const ${field["paramName"]}Value = ${canonical_expr(field)};
@@ -146,7 +146,7 @@ TEST(${name}Tests, BuilderFromSleRoundTrip)
 // 3) Verify wrapper throws when constructed from wrong ledger entry type.
 TEST(${name}Tests, WrapperThrowsOnWrongEntryType)
 {
-    UInt256 const index{3u};
+    constexpr UInt256 index{3};
 
     // Build a valid ledger entry of a different type
     // Ticket requires: Account, OwnerNode, TicketSequence, PreviousTxnID, PreviousTxnLgrSeq
@@ -177,7 +177,7 @@ TEST(${name}Tests, WrapperThrowsOnWrongEntryType)
 // 4) Verify builder throws when constructed from wrong ledger entry type.
 TEST(${name}Tests, BuilderThrowsOnWrongEntryType)
 {
-    UInt256 const index{4u};
+    constexpr UInt256 index{4};
 
     // Build a valid ledger entry of a different type
 % if wrong_le_include == "Ticket":
@@ -207,7 +207,7 @@ TEST(${name}Tests, BuilderThrowsOnWrongEntryType)
 // 5) Build with only required fields and verify optional fields return nullopt.
 TEST(${name}Tests, OptionalFieldsReturnNullopt)
 {
-    UInt256 const index{3u};
+    constexpr UInt256 index{3};
 
 % for field in required_fields:
     auto const ${field["paramName"]}Value = ${canonical_expr(field)};

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1781173989,
+        "lastModified": 1791130267,
-        "narHash": "sha256-fnzKKPvS+oieI/pTzotA5tkoM47EB1NpaBcgk4R97hE=",
+        "narHash": "sha256-1sjwcQMcgAbmiip/VivBSiK8p2bTkQGOvCuO7vnwfx4=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "8c91a71d13451abc40eb9dae8910f972f979852f",
+        "rev": "9013764fcc0ea99fa16cf7aa7decf8a5c3889dd2",
         "type": "github"
       },
       "original": {
@@ -47,11 +47,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1784611586,
+        "lastModified": 1791189933,
-        "narHash": "sha256-OfqgY+0hp/zseZB7uyH0U8kIDPS4scZZCyAurEplvG0=",
+        "narHash": "sha256-Y8eN7ki0Urx4Ojf4w1xSpWg8uk/3lJqK+E0Oth77rH0=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "14f58845249f3552a89b07772626b8d3c632fa86",
+        "rev": "e60029353d0c48d216bc4b065168ccd4079c166f",
         "type": "github"
       },
       "original": {

include/xrpl/basics/CountedObject.h

@@ -1,29 +1,31 @@
 #pragma once
 
-#include <xrpl/beast/type_name.h>
+#include <xrpl/beast/utility/instrumentation.h>
 
+#include <boost/core/type_name.hpp>
+
+#include <algorithm>
 #include <atomic>
+#include <cstddef>
+#include <cstdint>
+#include <iterator>
 #include <string>
+#include <type_traits>
 #include <utility>
-#include <vector>
 
 namespace xrpl {
 
 /**
  * Manages all counted object types.
+ *
+ * Counters register themselves on a lock-free intrusive list maintained
+ * by this object when constructed. Because counters are never destroyed
+ * or removed, the ABA problem does not apply.
+ *
+ * The registry is iterable as a forward range.
  */
 class CountedObjects
 {
-public:
-    static CountedObjects&
-    getInstance() noexcept;
-
-    using Entry = std::pair<std::string, int>;
-    using List = std::vector<Entry>;
-
-    [[nodiscard]] List
-    getCounts(int minimumThreshold) const;
-
 public:
     /**
      * Implementation for @ref CountedObject.
@@ -33,68 +35,147 @@ public:
     class Counter
     {
     public:
-        Counter(std::string name) noexcept : name_(std::move(name)), count_(0)
+        Counter(std::string name) noexcept;
-        {
-            // Insert ourselves at the front of the lock-free linked list
-            CountedObjects& instance = CountedObjects::getInstance();
-            Counter* head = nullptr;
 
-            do
+        // Counters are intrusive list nodes whose addresses are published
-            {
+        // in the registry; they must never be copied or moved. The atomic
-                head = instance.head_.load();
+        // members already force this, but we make it explicit.
-                next_ = head;
+        Counter(Counter const&) = delete;
-            } while (instance.head_.exchange(this) != head);
+        Counter&
+        operator=(Counter const&) = delete;
+        Counter(Counter&&) = delete;
+        Counter&
+        operator=(Counter&&) = delete;
 
-            ++instance.count_;
+        std::uint32_t
-        }
-
-        ~Counter() noexcept = default;
-
-        int
         increment() noexcept
         {
-            return ++count_;
+            auto const newCount = count_.fetch_add(1, std::memory_order::relaxed) + 1;
+            XRPL_ASSERT(newCount != 0, "xrpl::CountedObjects::Counter::increment : no overflow");
+
+            auto maxCount = maxCount_.load(std::memory_order::relaxed);
+
+            while (newCount > maxCount &&
+                   !maxCount_.compare_exchange_weak(maxCount, newCount, std::memory_order::relaxed))
+            {
+            }
+
+            return newCount;
         }
 
-        int
+        std::uint32_t
         decrement() noexcept
         {
-            return --count_;
+            auto const prev = count_.fetch_sub(1, std::memory_order::relaxed);
+            XRPL_ASSERT(prev != 0, "xrpl::CountedObjects::Counter::decrement : no underflow");
+            return prev - 1;
         }
 
-        [[nodiscard]] int
+        [[nodiscard]] std::uint32_t
-        getCount() const noexcept
+        count() const noexcept
         {
-            return count_.load();
+            return count_.load(std::memory_order::relaxed);
         }
 
-        [[nodiscard]] Counter*
+        [[nodiscard]] std::uint32_t
-        getNext() const noexcept
+        max() const noexcept
         {
-            return next_;
+            return std::max(
+                count_.load(std::memory_order::relaxed),
+                maxCount_.load(std::memory_order::relaxed));
         }
 
         [[nodiscard]] std::string const&
-        getName() const noexcept
+        name() const noexcept
         {
             return name_;
         }
 
     private:
+        friend class CountedObjects;
+
+        Counter* next_ = nullptr;
+        std::atomic<std::uint32_t> count_ = 0;
+        std::atomic<std::uint32_t> maxCount_ = 0;
         std::string const name_;
-        std::atomic<int> count_;
-        Counter* next_;
     };
 
-private:
+    class Iterator
-    CountedObjects() noexcept;
+    {
-    ~CountedObjects() noexcept = default;
+    public:
+        using value_type = Counter const;
+        using reference = value_type&;
+        using pointer = value_type*;
+        using difference_type = std::ptrdiff_t;
+        using iterator_category = std::forward_iterator_tag;
+
+        explicit Iterator(Counter* c = nullptr) noexcept : current_(c)
+        {
+        }
+
+        reference
+        operator*() const noexcept
+        {
+            return *current_;
+        }
+
+        pointer
+        operator->() const noexcept
+        {
+            return current_;
+        }
+
+        Iterator&
+        operator++() noexcept
+        {
+            current_ = current_->next_;
+            return *this;
+        }
+
+        Iterator
+        operator++(int) noexcept
+        {
+            auto tmp = *this;
+            ++*this;
+            return tmp;
+        }
+
+        bool
+        operator==(Iterator const&) const noexcept = default;
+
+    private:
+        Counter* current_;
+    };
+
+    constexpr CountedObjects() noexcept = default;
+
+    [[nodiscard]] auto
+    begin() const noexcept
+    {
+        return Iterator{head_.load(std::memory_order::acquire)};
+    }
+
+    [[nodiscard]] auto
+    end() const noexcept
+    {
+        return Iterator{};
+    }
 
 private:
-    std::atomic<int> count_;
+    std::atomic<Counter*> head_ = nullptr;
-    std::atomic<Counter*> head_;
 };
 
+/** The global counted object registry. */
+inline constinit CountedObjects gCountedObjects;
+
+inline CountedObjects::Counter::Counter(std::string name) noexcept
+    : next_(gCountedObjects.head_.load(std::memory_order::relaxed)), name_(std::move(name))
+{
+    while (!gCountedObjects.head_.compare_exchange_weak(
+        next_, this, std::memory_order::release, std::memory_order::relaxed))
+        ;
+}
+
 //------------------------------------------------------------------------------
 
 /**
@@ -103,27 +184,37 @@ private:
  * Derived classes have their instances counted automatically. This is used
  * for reporting purposes.
  *
+ * The constructors are private and `Object` is befriended so that the
+ * CRTP parameter must be the deriving class itself: a copy-paste error
+ * like `class B : public CountedObject<A>` fails to compile instead of
+ * silently polluting A's count.
+ *
+ * @note This class has no move operations by design: a derived class's
+ *       move constructor falls back to the copy constructor for this
+ *       base, so the newly created instance is counted. This keeps the
+ *       invariant that count is the number of outstanding subobjects.
+ *
+ * @warning Counted objects constructed during dynamic initialization of
+ *          other translation units may have their increments discarded when
+ *          counter itself is dynamically initialized. Do not create counted
+ *          objects before main() begins.
+ *
  * @ingroup basics
  */
 template <class Object>
+    requires std::is_class_v<Object>
 class CountedObject
 {
-private:
+    static inline CountedObjects::Counter counter{boost::core::type_name<Object>()};
-    static auto&
-    getCounter() noexcept
-    {
-        static CountedObjects::Counter kC{beast::typeName<Object>()};
-        return kC;
-    }
 
     CountedObject() noexcept
     {
-        getCounter().increment();
+        counter.increment();
     }
 
     CountedObject(CountedObject const&) noexcept
     {
-        getCounter().increment();
+        counter.increment();
     }
 
     CountedObject&
@@ -132,7 +223,7 @@ private:
 public:
     ~CountedObject() noexcept
     {
-        getCounter().decrement();
+        counter.decrement();
     }
 
     friend Object;

include/xrpl/basics/SlabAllocator.h

@@ -3,11 +3,11 @@
 #pragma once
 
 #include <xrpl/basics/ByteUtilities.h>
-#include <xrpl/beast/type_name.h>
 #include <xrpl/beast/utility/instrumentation.h>
 
 #include <boost/align.hpp>
 #include <boost/container/static_vector.hpp>
+#include <boost/core/type_name.hpp>
 #include <boost/predef.h>
 
 #include <algorithm>
@@ -16,6 +16,7 @@
 #include <cstring>
 #include <mutex>
 #include <stdexcept>
+#include <typeinfo>
 #include <vector>
 
 #if BOOST_OS_LINUX
@@ -335,7 +336,7 @@ public:
                 }) != cfg.end())
         {
             throw std::runtime_error(
-                "SlabAllocatorSet<" + beast::typeName<Type>() + ">: duplicate slab size");
+                "SlabAllocatorSet<" + boost::core::type_name<Type>() + ">: duplicate slab size");
         }
 
         for (auto const& c : cfg)

include/xrpl/basics/contract.h

@@ -1,7 +1,8 @@
 #pragma once
 
 #include <xrpl/basics/sanitizers.h>
-#include <xrpl/beast/type_name.h>
+
+#include <boost/core/type_name.hpp>
 
 #include <exception>
 #include <string>
@@ -55,7 +56,7 @@ Throw(Args&&... args)
         std::is_convertible_v<E*, std::exception*>, "Exception must derive from std::exception.");
 
     E e(std::forward<Args>(args)...);
-    logThrow(std::string("Throwing exception of type " + beast::typeName<E>() + ": ") + e.what());
+    logThrow("Throwing exception of type " + boost::core::type_name<E>() + ": " + e.what());
     throw std::move(e);
 }
 

include/xrpl/basics/enum_bitops.h

@@ -0,0 +1,200 @@
+#pragma once
+
+#include <concepts>
+#include <type_traits>
+#include <utility>
+
+namespace xrpl {
+
+/**
+ * Opt-in bitwise operators for scoped enumerations.
+ *
+ * Provides `&`, `|`, `^`, `~` and the corresponding compound assignment forms
+ * for any scoped enumeration with an unsigned underlying type that opts in by
+ * specializing @ref OptIn:
+ *
+ * @code
+ * namespace xrpl {
+ *
+ * enum class MyFlags : std::uint32_t { a = 1, b = 2, c = 4 };
+ *
+ * template <>
+ * struct enum_bitops::OptIn<MyFlags> : std::true_type {};
+ *
+ * }  // namespace xrpl
+ * @endcode
+ *
+ * The operators are constexpr and noexcept, and return the enumeration type.
+ *
+ * @par Where the specialization may be declared
+ *   In namespace xrpl, or at global scope with full qualification, and after
+ *   the enumeration is defined but before the operators are first used. This
+ *   cannot be done in a nested namespace or at class scope; for enumerations
+ *   nested in a class this means after the class definition.
+ *
+ * @par Where the operators are found
+ *   The operators are declared in namespace xrpl, so argument-dependent lookup
+ *   will find them only for enumerations declared in xrpl or nested in a class
+ *   declared directly in xrpl. Enumerations in a nested namespace will only be
+ *   found from code inside xrpl, and only if no enclosing scope declares an
+ *   operator of the same name; elsewhere they require using-declarations.
+ */
+namespace enum_bitops {
+
+/**
+ * Types that may be opted in to the bitwise operators.
+ *
+ * Satisfied by a scoped enumeration whose underlying type is an unsigned
+ * integer type.
+ *
+ * @tparam T The type to test.
+ */
+template <typename T>
+concept Eligible = std::is_scoped_enum_v<T> && std::unsigned_integral<std::underlying_type_t<T>>;
+
+/**
+ * Opt-in switch for the bitwise operators.
+ *
+ * The primary template derives from std::false_type. Specialize it to derive
+ * from std::true_type to enable the operators for an @ref Eligible enumeration.
+ *
+ * @tparam T The scoped enumeration to opt in.
+ */
+template <Eligible T>
+struct OptIn : std::false_type
+{
+};
+
+/**
+ * Enumerations for which the bitwise operators are enabled.
+ *
+ * Satisfied when @p T satisfies @ref Eligible and @ref OptIn has been
+ * specialized for it to derive from std::true_type.
+ *
+ * @tparam T The type to test.
+ */
+template <typename T>
+concept Candidate = Eligible<T> && OptIn<T>::value;
+
+}  // namespace enum_bitops
+
+// These are declared in xrpl, not in enum_bitops, so that argument-dependent
+// lookup finds them for enumerations whose associated namespace is xrpl.
+
+/**
+ * @name Bitwise operators for opted-in scoped enumerations
+ *
+ * Each operator applies the corresponding built-in operator to the
+ * underlying values and converts the result back to the enumeration type.
+ * Both operands must have the same enumeration type; there is no implicit
+ * conversion to or from the underlying type.
+ */
+/** @{ */
+
+/**
+ * Bitwise AND.
+ *
+ * @param lhs The left operand.
+ * @param rhs The right operand.
+ * @return The bits set in both @p lhs and @p rhs.
+ */
+template <enum_bitops::Candidate T>
+constexpr T
+operator&(T lhs, T rhs) noexcept
+{
+    return static_cast<T>(std::to_underlying(lhs) & std::to_underlying(rhs));
+}
+
+/**
+ * Bitwise OR.
+ *
+ * @param lhs The left operand.
+ * @param rhs The right operand.
+ * @return The bits set in @p lhs, in @p rhs, or in both.
+ */
+template <enum_bitops::Candidate T>
+constexpr T
+operator|(T lhs, T rhs) noexcept
+{
+    return static_cast<T>(std::to_underlying(lhs) | std::to_underlying(rhs));
+}
+
+/**
+ * Bitwise exclusive OR.
+ *
+ * @param lhs The left operand.
+ * @param rhs The right operand.
+ * @return The bits set in exactly one of @p lhs and @p rhs.
+ */
+template <enum_bitops::Candidate T>
+constexpr T
+operator^(T lhs, T rhs) noexcept
+{
+    return static_cast<T>(std::to_underlying(lhs) ^ std::to_underlying(rhs));
+}
+
+/**
+ * Bitwise complement.
+ *
+ * The result has every bit of the underlying type that is clear in
+ * @p val, including bits that no enumerator names. It is intended for
+ * clearing flags, as in `flags & ~flag`.
+ *
+ * @param val The operand.
+ * @return The complement of @p val.
+ */
+template <enum_bitops::Candidate T>
+constexpr T
+operator~(T val) noexcept
+{
+    return static_cast<T>(~std::to_underlying(val));
+}
+
+/**
+ * Bitwise AND assignment.
+ *
+ * @param lhs The value to modify.
+ * @param rhs The right operand.
+ * @return A reference to @p lhs.
+ */
+template <enum_bitops::Candidate T>
+constexpr T&
+operator&=(T& lhs, T rhs) noexcept
+{
+    lhs = lhs & rhs;
+    return lhs;
+}
+
+/**
+ * Bitwise OR assignment.
+ *
+ * @param lhs The value to modify.
+ * @param rhs The right operand.
+ * @return A reference to @p lhs.
+ */
+template <enum_bitops::Candidate T>
+constexpr T&
+operator|=(T& lhs, T rhs) noexcept
+{
+    lhs = lhs | rhs;
+    return lhs;
+}
+
+/**
+ * Bitwise exclusive OR assignment.
+ *
+ * @param lhs The value to modify.
+ * @param rhs The right operand.
+ * @return A reference to @p lhs.
+ */
+template <enum_bitops::Candidate T>
+constexpr T&
+operator^=(T& lhs, T rhs) noexcept
+{
+    lhs = lhs ^ rhs;
+    return lhs;
+}
+
+/** @} */
+
+}  // namespace xrpl

include/xrpl/basics/safe_cast.h

@@ -2,107 +2,212 @@
 
 #include <xrpl/beast/utility/instrumentation.h>  // IWYU pragma: keep
 
+#include <concepts>
+#include <cstdint>
+#include <limits>
+#include <memory>
 #include <type_traits>
+#include <utility>
 
 namespace xrpl {
 
-// safe_cast adds compile-time checks to a static_cast to ensure that
+/** Every value of @p Src can be represented by @p Dest.
-// the destination can hold all values of the source.  This is particularly
-// handy when the source or destination is an enumeration type.
 
-template <class Src, class Dest>
+    Given two integral types, the cast is safe when the destination can
-concept SafeToCast = (std::is_integral_v<Src> && std::is_integral_v<Dest>) &&
+    hold every possible value of the source.
-    (std::is_signed_v<Src> || std::is_unsigned_v<Dest>) &&
-    (std::is_signed_v<Src> != std::is_signed_v<Dest> ? sizeof(Dest) > sizeof(Src)
-                                                     : sizeof(Dest) >= sizeof(Src));
 
-template <class Dest, class Src>
+    Comparing the bounds requires care: we use @c std::cmp_less_equal and
+    @c std::cmp_greater_equal; the plain relational operators would apply
+    arithmetic conversions, resulting in incorrect results when comparing
+    across signedness.
+
+    Because @c std::cmp_* requires standard signed or unsigned integer
+    arguments, which excludes character types and bool, we first widen
+    all type bounds to the maximum-width integer type while preserving
+    signedness.
+
+    @note Extended integer types, like __int128 on gcc, cannot be safely
+          widened to a standard integer type, so the concept will reject
+          them.
+*/
+template <typename Src, typename Dest>
+concept SafeToCast = std::is_integral_v<Src> && std::is_integral_v<Dest> && []() consteval {
+    using WideSrc = std::conditional_t<std::is_signed_v<Src>, std::intmax_t, std::uintmax_t>;
+    using WideDest = std::conditional_t<std::is_signed_v<Dest>, std::intmax_t, std::uintmax_t>;
+
+    // Note: this guard must be an evaluated branch, and not a
+    // static_assert. The lambda body is outside the immediate
+    // context, so a substitution-time failure here would be a
+    // hard error rather than leaving the concept unsatisfied.
+    if constexpr (sizeof(Src) > sizeof(WideSrc) || sizeof(Dest) > sizeof(WideDest))
+    {
+        return false;
+    }
+    else
+    {
+        return std::cmp_less_equal(
+                   static_cast<WideDest>(std::numeric_limits<Dest>::min()),
+                   static_cast<WideSrc>(std::numeric_limits<Src>::min())) &&
+            std::cmp_greater_equal(
+                   static_cast<WideDest>(std::numeric_limits<Dest>::max()),
+                   static_cast<WideSrc>(std::numeric_limits<Src>::max()));
+    }
+}();
+
+/** Compile-time-checked static_cast that rejects non-value preserving casts.
+
+    @note There is deliberately no enum-to-enum overload, and no overload
+          returning the underlying type of an enum. For the latter, use
+          @c std::to_underlying.
+*/
+/** @{ */
+template <typename Dest, typename Src>
+    requires(std::is_integral_v<Dest> && std::is_integral_v<Src>)
 constexpr Dest
 safeCast(Src s) noexcept
-    requires(std::is_integral_v<Dest> && std::is_integral_v<Src>)
 {
     static_assert(
-        std::is_signed_v<Dest> || std::is_unsigned_v<Src>, "Cannot cast signed to unsigned");
+        SafeToCast<Src, Dest>, "This cast is not value-preserving. Please use unsafeCast instead.");
-    constexpr unsigned kNotSame = std::is_signed_v<Dest> != std::is_signed_v<Src>;
-    static_assert(
-        sizeof(Dest) >= sizeof(Src) + kNotSame,
-        "Destination is too small to hold all values of source");
     return static_cast<Dest>(s);
 }
 
-template <class Dest, class Src>
+template <typename Dest, typename Src>
+    requires(std::is_enum_v<Dest> && std::is_integral_v<Src>)
 constexpr Dest
 safeCast(Src s) noexcept
-    requires(std::is_enum_v<Dest> && std::is_integral_v<Src>)
 {
     return static_cast<Dest>(safeCast<std::underlying_type_t<Dest>>(s));
 }
 
-template <class Dest, class Src>
+template <typename Dest, typename Src>
+    requires(std::is_integral_v<Dest> && std::is_enum_v<Src>)
 constexpr Dest
 safeCast(Src s) noexcept
-    requires(std::is_integral_v<Dest> && std::is_enum_v<Src>)
 {
-    return safeCast<Dest>(static_cast<std::underlying_type_t<Src>>(s));
+    return safeCast<Dest>(std::to_underlying(s));
 }
+/** @} */
 
-// unsafe_cast explicitly flags a static_cast as not necessarily able to hold
+/** Integral-to-integral cast that is known to be narrowing or sign-erasing.
-// all values of the source. It includes a compile-time check so that if
-// underlying types become safe, it can be converted to a safe_cast.
 
-template <class Dest, class Src>
+    This explicitly flags a conversion that can lose information for some
+    values of the source type, where the call site accepts that loss (or
+    truncation is the intended behavior).
+
+    The compile-time check ensures the cast remains "unsafe": if the types
+    involved later change such that the conversion becomes inherently
+    value-preserving, the static assertion fires with instructions to
+    migrate the call site to @ref safeCast.
+
+    If the conversion's safety depends on a runtime precondition rather
+    than on the types, or varies across instantiations of generic code,
+    use @ref checkedCast instead.
+*/
+/** @{ */
+template <typename Dest, typename Src>
+    requires(std::is_integral_v<Dest> && std::is_integral_v<Src>)
 constexpr Dest
 unsafeCast(Src s) noexcept
-    requires(std::is_integral_v<Dest> && std::is_integral_v<Src>)
 {
     static_assert(
-        !SafeToCast<Src, Dest>,
+        !SafeToCast<Src, Dest>, "This cast is value-preserving. Please use safeCast instead.");
-        "Only unsafe if casting signed to unsigned or "
-        "destination is too small");
     return static_cast<Dest>(s);
 }
 
-template <class Dest, class Src>
+template <typename Dest, typename Src>
+    requires(std::is_enum_v<Dest> && std::is_integral_v<Src>)
 constexpr Dest
 unsafeCast(Src s) noexcept
-    requires(std::is_enum_v<Dest> && std::is_integral_v<Src>)
 {
     return static_cast<Dest>(unsafeCast<std::underlying_type_t<Dest>>(s));
 }
 
-template <class Dest, class Src>
+template <typename Dest, typename Src>
+    requires(std::is_integral_v<Dest> && std::is_enum_v<Src>)
 constexpr Dest
 unsafeCast(Src s) noexcept
-    requires(std::is_integral_v<Dest> && std::is_enum_v<Src>)
 {
-    return unsafeCast<Dest>(static_cast<std::underlying_type_t<Src>>(s));
+    return unsafeCast<Dest>(std::to_underlying(s));
+}
+/** @} */
+
+/** Integral-to-integral cast when the caller has performed a bounds check.
+
+    This documents that a runtime precondition or external invariant, which
+    is not necessarily visible to the compiler, guarantees that the requested
+    conversion is value-preserving for the values that can actually occur.
+
+    This is primarily meant for generic code, where the same expression may
+    be value-preserving for one instantiation but not for another, making
+    both @ref safeCast and @ref unsafeCast unusable.
+
+    Unlike @ref safeCast and @ref unsafeCast, this imposes no static check
+    on the type relationship: the caller's claim is about runtime values,
+    not about types.
+*/
+/** @{ */
+template <typename Dest, typename Src>
+    requires(std::is_integral_v<Dest> && std::is_integral_v<Src>)
+constexpr Dest
+checkedCast(Src s) noexcept
+{
+    return static_cast<Dest>(s);
 }
 
+template <typename Dest, typename Src>
+    requires(std::is_enum_v<Dest> && std::is_integral_v<Src>)
+constexpr Dest
+checkedCast(Src s) noexcept
+{
+    return static_cast<Dest>(checkedCast<std::underlying_type_t<Dest>>(s));
+}
+
+template <typename Dest, typename Src>
+    requires(std::is_integral_v<Dest> && std::is_enum_v<Src>)
+constexpr Dest
+checkedCast(Src s) noexcept
+{
+    return checkedCast<Dest>(std::to_underlying(s));
+}
+/** @} */
+
+/** Downcast within a class hierarchy, verified in debug builds.
+
+    Performs a static_cast down a hierarchy, but in debug builds verifies
+    via dynamic_cast that the object's dynamic type actually permits the
+    downcast. Both build modes execute the same conversion; debug builds
+    merely add the check.
+
+    The pointer form passes null through unchanged, as dynamic_cast does.
+
+    @note The check requires @p Src to be polymorphic; in release builds
+          an invalid downcast is undefined behavior on use, exactly as
+          with a bare static_cast.
+*/
+/** @{ */
 template <class Dest, class Src>
-    requires std::is_pointer_v<Dest>
+    requires(
+        std::is_pointer_v<Dest> && std::is_polymorphic_v<Src> &&
+        std::derived_from<std::remove_pointer_t<Dest>, Src> &&
+        (std::is_const_v<std::remove_pointer_t<Dest>> || !std::is_const_v<Src>) &&
+        (std::is_volatile_v<std::remove_pointer_t<Dest>> || !std::is_volatile_v<Src>))
 inline Dest
 safeDowncast(Src* s) noexcept
 {
-#ifdef NDEBUG
+    XRPL_ASSERT(
+        s == nullptr || dynamic_cast<Dest>(s) != nullptr, "xrpl::safeDowncast : valid downcast");
     return static_cast<Dest>(s);  // NOLINT(cppcoreguidelines-pro-type-static-cast-downcast)
-#else
-    auto* result = dynamic_cast<Dest>(s);
-    XRPL_ASSERT(result != nullptr, "xrpl::safeDowncast : pointer downcast is valid");
-    return result;
-#endif
 }
 
 template <class Dest, class Src>
-    requires std::is_lvalue_reference_v<Dest>
+    requires(
+        std::is_lvalue_reference_v<Dest> && std::is_polymorphic_v<Src> &&
+        std::derived_from<std::remove_reference_t<Dest>, Src>)
 inline Dest
 safeDowncast(Src& s) noexcept
 {
-#ifndef NDEBUG
+    return *safeDowncast<std::add_pointer_t<std::remove_reference_t<Dest>>>(std::addressof(s));
-    XRPL_ASSERT(
-        dynamic_cast<std::add_pointer_t<std::remove_reference_t<Dest>>>(&s) != nullptr,
-        "xrpl::safeDowncast : reference downcast is valid");
-#endif
-    return static_cast<Dest>(s);  // NOLINT(cppcoreguidelines-pro-type-static-cast-downcast)
 }
+/** @} */
 
 }  // namespace xrpl

include/xrpl/basics/spinlock.h

@@ -4,88 +4,215 @@
 
 #include <xrpl/beast/utility/instrumentation.h>
 
+#include <boost/predef/architecture.h>
+
 #include <atomic>
+#include <concepts>
 #include <limits>
 #include <type_traits>
 
-#ifndef __aarch64__
+#if BOOST_ARCH_X86
 #include <immintrin.h>
 #endif
 
 namespace xrpl {
 
+/** An unsigned integral type suitable for use as a spinlock.
+
+    The type must be always lock-free when wrapped in std::atomic, so
+    that lock operations cannot themselves take a (library-level) lock.
+ */
+template <typename T>
+concept SpinlockValueType = std::is_unsigned_v<T> && std::atomic<T>::is_always_lock_free;
+
+/** A spinlock value type that additionally supports the atomic bitwise
+    operations required to pack multiple locks into a single integer.
+ */
+template <typename T>
+concept PackedSpinlockValueType = SpinlockValueType<T> && requires(std::atomic<T>& a, T v) {
+    { a.fetch_or(v) } -> std::same_as<T>;
+    { a.fetch_and(v) } -> std::same_as<T>;
+};
+
 namespace detail {
-/**
+
- * Inform the processor that we are in a tight spin-wait loop.
+/** Inform the processor that we are in a tight spin-wait loop.
- *
+
- * Spinlocks caught in tight loops can result in the processor's pipeline
+    Spinlocks caught in tight loops can result in the processor's pipeline
- * filling up with comparison operations, resulting in a misprediction at
+    filling up with comparison operations, resulting in a misprediction at
- * the time the lock is finally acquired, necessitating pipeline flushing
+    the time the lock is finally acquired, necessitating pipeline flushing
- * which is ridiculously expensive and results in very high latency.
+    which is ridiculously expensive and results in very high latency.
- *
+
- * This function instructs the processor to "pause" for some architecture
+    This function instructs the processor to "pause" for some architecture
- * specific amount of time, to prevent this.
+    specific amount of time, to prevent this.
  */
 inline void
 spinPause() noexcept
 {
-#ifdef __aarch64__
+#if BOOST_ARCH_X86
-    asm volatile("yield");
-#else
     _mm_pause();
+#elif BOOST_ARCH_ARM
+    asm volatile("yield" ::: "memory");
+#else
+#error No implementation available for spinPause to use
 #endif
 }
 
 }  // namespace detail
 
-/** @{ */
+//------------------------------------------------------------------------------
-/**
- * Classes to handle arrays of spinlocks packed into a single atomic integer:
- *
- * Packed spinlocks allow for tremendously space-efficient lock-sharding
- * but they come at a cost.
- *
- * First, the implementation is necessarily low-level and uses advanced
- * features like memory ordering and highly platform-specific tricks to
- * maximize performance. This imposes a significant and ongoing cost to
- * developers.
- *
- * Second, and perhaps most important, is that the packing of multiple
- * locks into a single integer which, albeit space-efficient, also has
- * performance implications stemming from data dependencies, increased
- * cache-coherency traffic between processors and heavier loads on the
- * processor's load/store units.
- *
- * To be sure, these locks can have advantages but they are definitely
- * not general purpose locks and should not be thought of or used that
- * way. The use cases for them are likely few and far between; without
- * a compelling reason to use them, backed by profiling data, it might
- * be best to use one of the standard locking primitives instead. Note
- * that in most common platforms, `std::mutex` is so heavily optimized
- * that it can, usually, outperform spinlocks.
- *
- * @tparam T An unsigned integral type (e.g. std::uint16_t)
- */
 
-/**
+/** Attempt to acquire a spinlock without blocking.
- * A class that grabs a single packed spinlock from an atomic integer.
+
- *
+    @note This interface is primarily intended for one-shot attempts to
- * This class meets the requirements of Lockable:
+          acquire the lock. Avoid calling this function directly from a
- *     https://en.cppreference.com/w/cpp/named_req/Lockable
+          loop and use @ref spinLock instead.
+
+    @tparam T An unsigned integral type.
+    @param lock The atomic variable used as the lock.
+    @return true if the lock was acquired, false if it was already held.
  */
-template <class T>
+template <SpinlockValueType T>
+[[nodiscard]] bool
+spinTryLock(std::atomic<T>& lock) noexcept
+{
+    // A compare-exchange is required here, not an unconditional exchange:
+    // a failed attempt must not modify the lock word, in case the atomic
+    // is shared with PackedSpinlock).
+    T expected = 0;
+
+    return lock.compare_exchange_strong(
+        expected,
+        std::numeric_limits<T>::max(),
+        std::memory_order::acquire,
+        std::memory_order::relaxed);
+    ;
+}
+
+/** Acquire a spinlock, blocking until available.
+
+    Uses a TTAS (test-and-test-and-set) pattern, so waiters share the cache
+    line read-only, helping to avoid unnecessary coherency traffic.
+
+    @tparam T An unsigned integral type.
+    @param lock The atomic variable used as the lock.
+ */
+template <SpinlockValueType T>
+void
+spinLock(std::atomic<T>& lock) noexcept
+{
+    do
+    {
+        // Relaxed ordering is sufficient for the spin: this load is only
+        // a filter. The acquire on the successful exchange in spinTryLock
+        // is what synchronizes the critical section.
+        while (lock.load(std::memory_order::relaxed) != 0)
+            detail::spinPause();
+    } while (!spinTryLock(lock));
+}
+
+/** Release a spinlock.
+
+    @tparam T An unsigned integral type.
+    @param lock The atomic variable used as the lock.
+ */
+template <SpinlockValueType T>
+void
+spinUnlock(std::atomic<T>& lock) noexcept
+{
+    lock.store(0, std::memory_order::release);
+}
+
+//------------------------------------------------------------------------------
+
+/** A Lockable interface to a spinlock implemented on top of an atomic.
+
+    @tparam T An unsigned integral type.
+
+    @note Using `PackedSpinlock` and `Spinlock` against the same underlying
+          atomic integer is possible but can result in `Spinlock` not being
+          able to acquire the lock during periods of high contention due to
+          the way the two locks operate: `Spinlock` spins and tries to grab
+          all the bits at once, whereas any given `PackedSpinlock` instance
+          only tries to grab one bit at a time. Caveat emptor.
+
+    This class meets the requirements of Lockable:
+        https://en.cppreference.com/w/cpp/named_req/Lockable
+ */
+template <SpinlockValueType T>
+class Spinlock
+{
+    std::atomic<T>& lock_;
+
+public:
+    Spinlock(Spinlock const&) = delete;
+    Spinlock&
+    operator=(Spinlock const&) = delete;
+
+    /** Construct a spinlock handle.
+
+        @param lock The atomic integer to spin against.
+
+        @note For performance reasons, you should strive to have `lock` be
+              on a cacheline by itself.
+     */
+    explicit Spinlock(std::atomic<T>& lock) noexcept : lock_(lock)
+    {
+    }
+
+    [[nodiscard]] bool
+    try_lock() noexcept  // NOLINT(readability-identifier-naming)
+    {
+        return spinTryLock(lock_);
+    }
+
+    void
+    lock() noexcept
+    {
+        spinLock(lock_);
+    }
+
+    void
+    unlock() noexcept
+    {
+        spinUnlock(lock_);
+    }
+};
+
+//------------------------------------------------------------------------------
+
+/** A Lockable interface to a packed spinlock implemented on top of an atomic.
+
+    Packed spinlocks offer tremendous space-efficient lock-sharding but
+    they come at a cost.
+
+    First, the implementation is necessarily low-level and uses advanced
+    features like memory ordering and highly platform-specific tricks to
+    maximize performance. This imposes a significant and ongoing cost to
+    developers.
+
+    Second, and perhaps most important, is that the packing of multiple
+    locks into a single integer which, albeit space-efficient, also has
+    performance implications stemming from data dependencies, increased
+    cache-coherency traffic between processors and heavier loads on the
+    processor's load/store units.
+
+    To be sure, these locks can have advantages but they are definitely
+    not general purpose locks and should not be thought of or used that
+    way. The use cases for them are likely few and far between; without
+    a compelling reason to use them, backed by profiling data, it might
+    be best to use one of the standard locking primitives instead. Note
+    that in most common platforms, `std::mutex` is so heavily optimized
+    that it can, usually, outperform spinlocks.
+
+    @tparam T An unsigned integral type (e.g. std::uint16_t)
+
+    This class meets the requirements of Lockable:
+        https://en.cppreference.com/w/cpp/named_req/Lockable
+ */
+template <PackedSpinlockValueType T>
 class PackedSpinlock
 {
-    // clang-format off
-    static_assert(std::is_unsigned_v<T>);
-    static_assert(std::atomic<T>::is_always_lock_free);
-    static_assert(
-        std::is_same_v<decltype(std::declval<std::atomic<T>&>().fetch_or(0)), T> &&
-        std::is_same_v<decltype(std::declval<std::atomic<T>&>().fetch_and(0)), T>,
-        "std::atomic<T>::fetch_and(T) and std::atomic<T>::fetch_and(T) are required by packed_spinlock");
-    // clang-format on
-
-private:
     std::atomic<T>& bits_;
     T const mask_;
 
@@ -94,120 +221,49 @@ public:
     PackedSpinlock&
     operator=(PackedSpinlock const&) = delete;
 
-    /**
+    /** Construct a packed spinlock handle for a single bit.
-     * A single spinlock packed inside the specified atomic
+
-     *
+        @param lock The atomic integer inside which the spinlock is packed.
-     * @param lock The atomic integer inside which the spinlock is packed.
+        @param index The index of the spinlock this object acquires.
-     * @param index The index of the spinlock this object acquires.
+
-     *
+        @note For performance reasons, you should strive to have `lock` be
-     * @note For performance reasons, you should strive to have `lock` be
+              on a cacheline by itself.
-     *       on a cacheline by itself.
      */
-    PackedSpinlock(std::atomic<T>& lock, int index) : bits_(lock), mask_(static_cast<T>(1) << index)
+    PackedSpinlock(std::atomic<T>& lock, int index) noexcept
-    {
+        : bits_(lock), mask_([index]() {
-        XRPL_ASSERT(
+            XRPL_ASSERT(
-            index >= 0 && (mask_ != 0),
+                index >= 0 && index < std::numeric_limits<T>::digits,
-            "xrpl::PackedSpinlock::PackedSpinlock : valid index and mask");
+                "xrpl::PackedSpinlock::PackedSpinlock : valid index");
-    }
+            return static_cast<T>(T{1} << index);
-
+        }())
-    [[nodiscard]] bool
-    try_lock()  // NOLINT(readability-identifier-naming)
-    {
-        return (bits_.fetch_or(mask_, std::memory_order_acquire) & mask_) == 0;
-    }
-
-    void
-    lock()
-    {
-        while (!try_lock())
-        {
-            // The use of relaxed memory ordering here is intentional and
-            // serves to help reduce cache coherency traffic during times
-            // of contention by avoiding writes that would definitely not
-            // result in the lock being acquired.
-            while ((bits_.load(std::memory_order_relaxed) & mask_) != 0)
-                detail::spinPause();
-        }
-    }
-
-    void
-    unlock()
-    {
-        bits_.fetch_and(~mask_, std::memory_order_release);
-    }
-};
-
-/**
- * A spinlock implemented on top of an atomic integer.
- *
- * @note Using `packed_spinlock` and `spinlock` against the same underlying
- *       atomic integer can result in `spinlock` not being able to actually
- *       acquire the lock during periods of high contention, because of how
- *       the two locks operate: `spinlock` will spin trying to grab all the
- *       bits at once, whereas any given `packed_spinlock` will only try to
- *       grab one bit at a time. Caveat emptor.
- *
- * This class meets the requirements of Lockable:
- *     https://en.cppreference.com/w/cpp/named_req/Lockable
- */
-template <class T>
-class Spinlock
-{
-    static_assert(std::is_unsigned_v<T>);
-    static_assert(std::atomic<T>::is_always_lock_free);
-
-private:
-    std::atomic<T>& lock_;
-
-public:
-    Spinlock(Spinlock const&) = delete;
-    Spinlock&
-    operator=(Spinlock const&) = delete;
-
-    /**
-     * Grabs the
-     *
-     * @param lock The atomic integer to spin against.
-     *
-     * @note For performance reasons, you should strive to have `lock` be
-     *       on a cacheline by itself.
-     */
-    Spinlock(std::atomic<T>& lock) : lock_(lock)
     {
     }
 
     [[nodiscard]] bool
-    try_lock()  // NOLINT(readability-identifier-naming)
+    try_lock() noexcept  // NOLINT(readability-identifier-naming)
     {
-        T expected = 0;
+        return (bits_.fetch_or(mask_, std::memory_order::acquire) & mask_) == 0;
-
-        return lock_.compare_exchange_weak(
-            expected,
-            std::numeric_limits<T>::max(),
-            std::memory_order_acquire,
-            std::memory_order_relaxed);
     }
 
     void
-    lock()
+    lock() noexcept
     {
-        while (!try_lock())
+        do
         {
             // The use of relaxed memory ordering here is intentional and
             // serves to help reduce cache coherency traffic during times
-            // of contention by avoiding writes that would definitely not
+            // of contention by avoiding writes that are unlikely to grab
-            // result in the lock being acquired.
+            // the requested lock.
-            while (lock_.load(std::memory_order_relaxed) != 0)
+            while ((bits_.load(std::memory_order::relaxed) & mask_) != 0)
                 detail::spinPause();
-        }
+        } while (!try_lock());
     }
 
     void
-    unlock()
+    unlock() noexcept
     {
-        lock_.store(0, std::memory_order_release);
+        bits_.fetch_and(~mask_, std::memory_order::release);
     }
 };
-/** @} */
 
 }  // namespace xrpl

include/xrpl/beast/type_name.h

@@ -1,47 +0,0 @@
-#pragma once
-
-#include <cstdlib>
-#include <string>
-#include <type_traits>
-#include <typeinfo>
-
-#ifndef _MSC_VER
-#include <cxxabi.h>
-#endif
-
-namespace beast {
-
-template <typename T>
-std::string
-typeName()
-{
-    using TR = std::remove_reference_t<T>;
-
-    std::string name = typeid(TR).name();
-
-#ifndef _MSC_VER
-    if (auto s = abi::__cxa_demangle(name.c_str(), nullptr, nullptr, nullptr))
-    {
-        name = s;
-        // NOLINTNEXTLINE(cppcoreguidelines-no-malloc)
-        std::free(s);
-    }
-#endif
-
-    if (std::is_const_v<TR>)
-        name += " const";
-    if (std::is_volatile_v<TR>)
-        name += " volatile";
-    if (std::is_lvalue_reference_v<T>)
-    {
-        name += "&";
-    }
-    else if (std::is_rvalue_reference_v<T>)
-    {
-        name += "&&";
-    }
-
-    return name;
-}
-
-}  // namespace beast

include/xrpl/beast/utility/Zero.h

@@ -2,26 +2,24 @@
 
 #pragma once
 
+#include <compare>
+#include <concepts>
+
 namespace beast {
 
 /**
  * Zero allows classes to offer efficient comparisons to zero.
  *
- * Zero is a struct to allow classes to efficiently compare with zero without
- * requiring an rvalue construction.
- *
  * It's often the case that we have classes which combine a number and a unit.
  * In such cases, comparisons like t > 0 or t != 0 make sense, but comparisons
- * like t > 1 or t != 1 do not.
+ * like t > 1 or t != 1 do not. Comparing against kZero expresses exactly that,
+ * without constructing a T.
  *
- * The class Zero allows such comparisons to be easily made.
+ * A type T participates if either `t.signum()` or an unqualified `signum(t)`
- *
+ * found by argument-dependent lookup returns an integer that is negative,
- * The comparing class T either needs to have a method called signum() which
+ * zero, or positive according to the sign of t. Both `t == kZero` and
- * returns a positive number, 0, or a negative; or there needs to be a signum
+ * `kZero == t` work, as do all six relational operators in either order.
- * function which resolves in the namespace which takes an instance of T and
- * returns a positive, zero or negative number.
  */
-
 struct Zero
 {
     explicit Zero() = default;
@@ -30,115 +28,44 @@ struct Zero
 inline constexpr Zero kZero{};
 
 /**
- * Default implementation of signum calls the method on the class.
+ * Default implementation of signum: call the member function.
  */
-template <typename T>
+template <class T>
-auto
+    requires requires(T const& t) {
-signum(T const& t)
+        { t.signum() } -> std::integral;
+    }
+[[nodiscard]] constexpr auto
+signum(T const& t) noexcept(noexcept(t.signum()))
 {
     return t.signum();
 }
 
-namespace detail::zero_helper {
+namespace detail {
 
-// For argument dependent lookup to function properly, calls to signum must
+/**
-// be made from a namespace that does not include overloads of the function..
+ * A type with a usable signum: either the member-based default above, or a
+ * `signum(t)` overload in T's own namespace, found by ADL. A user overload
+ * that is a better match than the template wins, as usual.
+ */
 template <class T>
-auto
+concept HasSignum = requires(T const& t) {
-callSignum(T const& t)
+    { signum(t) } -> std::integral;
+};
+
+}  // namespace detail
+
+template <detail::HasSignum T>
+[[nodiscard]] constexpr bool
+operator==(T const& t, Zero) noexcept(noexcept(signum(t)))
 {
-    return signum(t);
+    return signum(t) == 0;
 }
 
-}  // namespace detail::zero_helper
+template <detail::HasSignum T>
-
+[[nodiscard]] constexpr std::strong_ordering
-// Handle operators where T is on the left side using signum.
+operator<=>(T const& t, Zero) noexcept(noexcept(signum(t)))
-
-template <typename T>
-bool
-operator==(T const& t, Zero)
 {
-    return detail::zero_helper::callSignum(t) == 0;
+    return signum(t) <=> 0;
-}
-
-template <typename T>
-bool
-operator!=(T const& t, Zero)
-{
-    return detail::zero_helper::callSignum(t) != 0;
-}
-
-template <typename T>
-bool
-operator<(T const& t, Zero)
-{
-    return detail::zero_helper::callSignum(t) < 0;
-}
-
-template <typename T>
-bool
-operator>(T const& t, Zero)
-{
-    return detail::zero_helper::callSignum(t) > 0;
-}
-
-template <typename T>
-bool
-operator>=(T const& t, Zero)
-{
-    return detail::zero_helper::callSignum(t) >= 0;
-}
-
-template <typename T>
-bool
-operator<=(T const& t, Zero)
-{
-    return detail::zero_helper::callSignum(t) <= 0;
-}
-
-// Handle operators where T is on the right side by
-// reversing the operation, so that T is on the left side.
-
-template <typename T>
-bool
-operator==(Zero, T const& t)
-{
-    return t == kZero;
-}
-
-template <typename T>
-bool
-operator!=(Zero, T const& t)
-{
-    return t != kZero;
-}
-
-template <typename T>
-bool
-operator<(Zero, T const& t)
-{
-    return t > kZero;
-}
-
-template <typename T>
-bool
-operator>(Zero, T const& t)
-{
-    return t < kZero;
-}
-
-template <typename T>
-bool
-operator>=(Zero, T const& t)
-{
-    return t <= kZero;
-}
-
-template <typename T>
-bool
-operator<=(Zero, T const& t)
-{
-    return t >= kZero;
 }
 
 }  // namespace beast

include/xrpl/ledger/ApplyView.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include <xrpl/basics/base_uint.h>
-#include <xrpl/basics/safe_cast.h>
+#include <xrpl/basics/enum_bitops.h>
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/ledger/OwnerCounts.h>
 #include <xrpl/ledger/ReadView.h>
@@ -22,80 +22,39 @@
 
 namespace xrpl {
 
-// Bitwise flag enum with existing operator overloads
+enum class ApplyFlags : std::uint32_t {
-// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
+    None = 0x00,
-enum ApplyFlags : std::uint32_t {
-    TapNone = 0x00,
 
     // This is a local transaction with the
     // fail_hard flag set.
-    TapFailHard = 0x10,
+    FailHard = 0x10,
 
     // This is not the transaction's last pass
     // Transaction can be retried, soft failures allowed
-    TapRetry = 0x20,
+    Retry = 0x20,
 
     // Transaction came from a privileged source
-    TapUnlimited = 0x400,
+    Unlimited = 0x400,
 
     // Transaction is executing as part of a batch
-    TapBatch = 0x800,
+    Batch = 0x800,
 
     // Transaction shouldn't be applied
     // Signatures shouldn't be checked
-    TapDryRun = 0x1000,
+    DryRun = 0x1000,
 
     // Transaction is being preflighted as the payload of a
     // TransactionProposalCreate. Its signatures are collected on-ledger
     // afterward, so signature-presence checks (e.g. Batch signer matching)
     // are skipped at proposal-creation time (On-Chain Cosigner spec
     // §5.3.1.2).
-    TapProposal = 0x2000
+    Proposal = 0x2000
 };
 
-constexpr ApplyFlags
+template <>
-operator|(ApplyFlags const& lhs, ApplyFlags const& rhs)
+struct enum_bitops::OptIn<ApplyFlags> : std::true_type
 {
-    return safeCast<ApplyFlags>(
+};
-        safeCast<std::underlying_type_t<ApplyFlags>>(lhs) |
-        safeCast<std::underlying_type_t<ApplyFlags>>(rhs));
-}
-
-static_assert((TapFailHard | TapRetry) == safeCast<ApplyFlags>(0x30u), "ApplyFlags operator |");
-static_assert((TapRetry | TapFailHard) == safeCast<ApplyFlags>(0x30u), "ApplyFlags operator |");
-
-constexpr ApplyFlags
-operator&(ApplyFlags const& lhs, ApplyFlags const& rhs)
-{
-    return safeCast<ApplyFlags>(
-        safeCast<std::underlying_type_t<ApplyFlags>>(lhs) &
-        safeCast<std::underlying_type_t<ApplyFlags>>(rhs));
-}
-
-static_assert((TapFailHard & TapRetry) == TapNone, "ApplyFlags operator &");
-static_assert((TapRetry & TapFailHard) == TapNone, "ApplyFlags operator &");
-
-constexpr ApplyFlags
-operator~(ApplyFlags const& flags)
-{
-    return safeCast<ApplyFlags>(~safeCast<std::underlying_type_t<ApplyFlags>>(flags));
-}
-
-static_assert(~TapRetry == safeCast<ApplyFlags>(0xFFFFFFDFu), "ApplyFlags operator ~");
-
-inline ApplyFlags
-operator|=(ApplyFlags& lhs, ApplyFlags const& rhs)
-{
-    lhs = lhs | rhs;
-    return lhs;
-}
-
-inline ApplyFlags
-operator&=(ApplyFlags& lhs, ApplyFlags const& rhs)
-{
-    lhs = lhs & rhs;
-    return lhs;
-}
 
 //------------------------------------------------------------------------------
 

include/xrpl/ledger/entries/LedgerHashesEntry.h

@@ -1,11 +1,17 @@
 #pragma once
 
+#include <xrpl/basics/base_uint.h>
 #include <xrpl/beast/utility/Journal.h>
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
 #include <xrpl/ledger/entries/SLEBase.h>
 #include <xrpl/protocol/Indexes.h>
 #include <xrpl/protocol/LedgerFormats.h>
+#include <xrpl/protocol/SField.h>
+#include <xrpl/protocol/STVector256.h>
+
+#include <cstddef>
+#include <optional>
 
 namespace xrpl {
 
@@ -25,6 +31,31 @@ public:
         : Base(keylet::skip(), view, j)
     {
     }
+
+    /**
+     * Looks up a hash `diff` slots back from the most recent entry in the
+     * sfHashes vector (diff == 0 is the most recent entry).
+     *
+     * Callers decide which skip list entry to read and how to translate a
+     * target ledger sequence into `diff`; this only does the bounds check
+     * and vector indexing shared by both the recent (stride 1) and distant
+     * (stride 256) skip lists.
+     *
+     * @param diff how many slots back from the most recent hash to look up;
+     * 0 is the most recent hash.
+     * @return the hash at that slot, or std::nullopt if the entry does not
+     * exist or `diff` is out of range.
+     */
+    [[nodiscard]] std::optional<UInt256>
+    hashAt(std::size_t diff) const
+    {
+        if (!this->exists())
+            return std::nullopt;
+        STVector256 const vec = (*this)->getFieldV256(sfHashes);
+        if (vec.size() > diff)
+            return vec[vec.size() - diff - 1];
+        return std::nullopt;
+    }
 };
 
 using LedgerHashesEntryR = LedgerHashesEntry<ReadView>;

include/xrpl/nodestore/detail/DecodedBlob.h

@@ -1,8 +1,10 @@
 #pragma once
 
+#include <xrpl/basics/base_uint.h>
 #include <xrpl/nodestore/NodeObject.h>
 
 #include <memory>
+#include <optional>
 
 namespace xrpl::node_store {
 
@@ -23,7 +25,7 @@ public:
     /**
      * Construct the decoded blob from raw data.
      */
-    DecodedBlob(void const* key, void const* value, int valueBytes);
+    DecodedBlob(std::optional<uint256> key, void const* value, int valueBytes);
 
     /**
      * Determine if the decoding was successful.
@@ -43,10 +45,10 @@ public:
 private:
     bool success_{false};
 
-    void const* key_;
+    uint256 key_;
     NodeObjectType objectType_{NodeObjectType::Unknown};
     unsigned char const* objectData_{nullptr};
-    int dataBytes_;
+    int dataBytes_ = 0;
 };
 
 }  // namespace xrpl::node_store

include/xrpl/nodestore/detail/EncodedBlob.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <xrpl/basics/base_uint.h>
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/nodestore/NodeObject.h>
 
@@ -37,11 +38,6 @@ namespace xrpl::node_store {
 
 class EncodedBlob
 {
-    /**
-     * The 32-byte key of the serialized object.
-     */
-    std::array<std::uint8_t, 32> key_{};
-
     /**
      * A pre-allocated buffer for the serialized object.
      *
@@ -65,6 +61,11 @@ class EncodedBlob
      */
     std::uint8_t* const ptr_;
 
+    /**
+     * The 32-byte key of the serialized object.
+     */
+    uint256 key_;
+
 public:
     explicit EncodedBlob(std::shared_ptr<NodeObject> const& obj)
         : size_([&obj]() {
@@ -76,11 +77,12 @@ public:
             return obj->getData().size() + 9;
         }())
         , ptr_((size_ <= payload_.size()) ? payload_.data() : new std::uint8_t[size_])
+        , key_(obj->getHash())
     {
         std::fill_n(ptr_, 8, std::uint8_t{0});
         ptr_[8] = static_cast<std::uint8_t>(obj->getType());
+
         std::copy_n(obj->getData().data(), obj->getData().size(), ptr_ + 9);
-        std::copy_n(obj->getHash().data(), obj->getHash().size(), key_.data());
     }
 
     ~EncodedBlob()
@@ -95,10 +97,10 @@ public:
             delete[] ptr_;
     }
 
-    [[nodiscard]] void const*
+    [[nodiscard]] uint256 const&
     getKey() const noexcept
     {
-        return static_cast<void const*>(key_.data());
+        return key_;
     }
 
     [[nodiscard]] std::size_t

include/xrpl/protocol/AccountID.h

@@ -61,14 +61,22 @@ parseBase58(std::string const& s);
 /**
  * A special account that's used as the "issuer" for XRP.
  */
-AccountID const&
+constexpr inline AccountID const&
-xrpAccount();
+xrpAccount() noexcept
+{
+    static constexpr AccountID kAccount(beast::kZero);
+    return kAccount;
+}
 
 /**
  * A placeholder for empty accounts.
  */
-AccountID const&
+constexpr inline AccountID const&
-noAccount();
+noAccount() noexcept
+{
+    static constexpr AccountID kAccount = xrpAccount().next();
+    return kAccount;
+}
 
 /**
  * Convert hex or base58 string to AccountID.
@@ -80,10 +88,10 @@ bool
 toIssuer(AccountID&, std::string const&);
 
 // DEPRECATED Should be checking the currency or native flag
-inline bool
+constexpr inline bool
-isXRP(AccountID const& c)
+isXRP(AccountID const& c) noexcept
 {
-    return c == beast::kZero;
+    return c == xrpAccount();
 }
 
 // DEPRECATED
@@ -101,22 +109,6 @@ operator<<(std::ostream& os, AccountID const& x)
     return os;
 }
 
-/**
- * Initialize the global cache used to map AccountID to base58 conversions.
- *
- * The cache is optional and need not be initialized. But because conversion
- * is expensive (it requires a SHA-256 operation) in most cases the overhead
- * of the cache is worth the benefit.
- *
- * @param count The number of entries the cache should accommodate. Zero will
- *              disable the cache, releasing any memory associated with it.
- *
- * @note The function will only initialize the cache the first time it is
- *       invoked. Subsequent invocations do nothing.
- */
-void
-initAccountIdCache(std::size_t count);
-
 }  // namespace xrpl
 
 //------------------------------------------------------------------------------

include/xrpl/protocol/KnownFormats.h

@@ -1,10 +1,10 @@
 #pragma once
 
 #include <xrpl/basics/contract.h>
-#include <xrpl/beast/type_name.h>
 #include <xrpl/protocol/SOTemplate.h>
 
 #include <boost/container/flat_map.hpp>
+#include <boost/core/type_name.hpp>
 
 #include <algorithm>
 #include <cstddef>
@@ -84,7 +84,7 @@ public:
      * Derived classes will load the object with all the known formats.
      */
 private:
-    KnownFormats() : name_(beast::typeName<Derived>())
+    KnownFormats() : name_(boost::core::type_name<Derived>())
     {
     }
 

include/xrpl/protocol/STBitString.h

@@ -33,7 +33,20 @@ public:
 
     STBitString(SField const& n);
     STBitString(value_type const& v);
+
+    template <typename Tag>
+        requires(!std::is_void_v<Tag>)
+    STBitString(BaseUInt<Bits, Tag> const& v) : value_(v)
+    {
+    }
+
     STBitString(SField const& n, value_type const& v);
+    template <typename Tag>
+        requires(!std::is_void_v<Tag>)
+    STBitString(SField const& n, BaseUInt<Bits, Tag> const& v) : STBase(n), value_(v)
+    {
+    }
+
     STBitString(SerialIter& sit, SField const& name);
 
     [[nodiscard]] SerializedTypeID
@@ -166,7 +179,7 @@ template <typename Tag>
 void
 STBitString<Bits>::setValue(BaseUInt<Bits, Tag> const& v)
 {
-    value_ = v;
+    value_ = value_type{v};
 }
 
 template <int Bits>

include/xrpl/protocol/STPathSet.h

@@ -2,6 +2,7 @@
 
 #include <xrpl/basics/CountedObject.h>
 #include <xrpl/basics/UnorderedContainers.h>
+#include <xrpl/basics/enum_bitops.h>
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/json/json_value.h>
 #include <xrpl/protocol/AccountID.h>
@@ -15,6 +16,7 @@
 #include <cstdint>
 #include <memory>
 #include <optional>
+#include <type_traits>
 #include <utility>
 #include <vector>
 
@@ -22,18 +24,8 @@ namespace xrpl {
 
 class STPathElement final : public CountedObject<STPathElement>
 {
-    unsigned int type_;
-    AccountID accountID_;
-    PathAsset assetID_;
-    AccountID issuerID_;
-
-    bool isOffer_;
-    std::size_t hashValue_;
-
 public:
-    // Bitwise values (typeCurrency | typeMPT)
+    enum class Type : std::uint8_t {
-    // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
-    enum Type {
         TypeNone = 0x00,
         TypeAccount = 0x01,   // Rippling through an account (vs taking an offer).
         TypeCurrency = 0x10,  // Currency follows.
@@ -45,6 +37,8 @@ public:
         // Combination of all types.
     };
 
+    using enum Type;
+
     STPathElement();
     STPathElement(STPathElement const&) = default;
     STPathElement&
@@ -62,42 +56,42 @@ public:
         bool forceAsset = false);
 
     STPathElement(
-        unsigned int uType,
+        Type type,
         AccountID const& account,
         PathAsset const& asset,
         AccountID const& issuer);
 
-    [[nodiscard]] std::uint32_t
+    [[nodiscard]] Type
-    getNodeType() const;
+    getNodeType() const noexcept;
 
     [[nodiscard]] bool
-    isOffer() const;
+    isOffer() const noexcept;
 
     [[nodiscard]] bool
-    isAccount() const;
+    isAccount() const noexcept;
 
     [[nodiscard]] bool
-    hasIssuer() const;
+    hasIssuer() const noexcept;
 
     [[nodiscard]] bool
-    hasCurrency() const;
+    hasCurrency() const noexcept;
 
     [[nodiscard]] bool
-    hasMPT() const;
+    hasMPT() const noexcept;
 
     [[nodiscard]] bool
-    hasAsset() const;
+    hasAsset() const noexcept;
 
     [[nodiscard]] bool
-    isNone() const;
+    isNone() const noexcept;
 
     // Nodes are either an account ID or a offer prefix. Offer prefixs denote a
     // class of offers.
     [[nodiscard]] AccountID const&
-    getAccountID() const;
+    getAccountID() const noexcept;
 
     [[nodiscard]] PathAsset const&
-    getPathAsset() const;
+    getPathAsset() const noexcept;
 
     [[nodiscard]] Currency const&
     getCurrency() const;
@@ -106,17 +100,35 @@ public:
     getMPTID() const;
 
     [[nodiscard]] AccountID const&
-    getIssuerID() const;
+    getIssuerID() const noexcept;
 
     [[nodiscard]] bool
-    isType(Type const& pe) const;
+    isType(Type pe) const noexcept;
 
-    bool
+    friend bool
-    operator==(STPathElement const& t) const;
+    operator==(STPathElement const& lhs, STPathElement const& rhs) noexcept
+    {
+        return lhs.isType(TypeAccount) == rhs.isType(TypeAccount) &&
+            lhs.hashValue_ == rhs.hashValue_ && lhs.accountID_ == rhs.accountID_ &&
+            lhs.assetID_ == rhs.assetID_ && lhs.issuerID_ == rhs.issuerID_;
+    }
 
 private:
     static std::size_t
     getHash(STPathElement const& element);
+
+    Type type_;
+    AccountID accountID_;
+    PathAsset assetID_;
+    AccountID issuerID_;
+
+    bool isOffer_;
+    std::size_t hashValue_;
+};
+
+template <>
+struct enum_bitops::OptIn<STPathElement::Type> : std::true_type
+{
 };
 
 template <class Hasher>
@@ -124,7 +136,7 @@ void
 hash_append(Hasher& h, STPathElement const& e) noexcept
 {
     using beast::hash_append;
-    hash_append(h, (e.getNodeType() & STPathElement::TypeAccount) != 0u);
+    hash_append(h, e.isType(STPathElement::TypeAccount));
     hash_append(h, e.getAccountID());
     hash_append(h, e.getPathAsset());
     hash_append(h, e.getIssuerID());
@@ -404,11 +416,11 @@ inline STPathElement::STPathElement(
 }
 
 inline STPathElement::STPathElement(
-    unsigned int uType,
+    Type type,
     AccountID const& account,
     PathAsset const& asset,
     AccountID const& issuer)
-    : type_(uType)
+    : type_(type)
     , accountID_(account)
     , assetID_(asset)
     , issuerID_(issuer)
@@ -423,56 +435,56 @@ inline STPathElement::STPathElement(
     hashValue_ = getHash(*this);
 }
 
-inline std::uint32_t
+inline STPathElement::Type
-STPathElement::getNodeType() const
+STPathElement::getNodeType() const noexcept
 {
     return type_;
 }
 
 inline bool
-STPathElement::isOffer() const
+STPathElement::isOffer() const noexcept
 {
     return isOffer_;
 }
 
 inline bool
-STPathElement::isAccount() const
+STPathElement::isAccount() const noexcept
 {
     return !isOffer();
 }
 
 inline bool
-STPathElement::isType(Type const& pe) const
+STPathElement::isType(Type pe) const noexcept
 {
-    return (type_ & pe) != 0u;
+    return (type_ & pe) != STPathElement::TypeNone;
 }
 
 inline bool
-STPathElement::hasIssuer() const
+STPathElement::hasIssuer() const noexcept
 {
     return isType(STPathElement::TypeIssuer);
 }
 
 inline bool
-STPathElement::hasCurrency() const
+STPathElement::hasCurrency() const noexcept
 {
     return isType(STPathElement::TypeCurrency);
 }
 
 inline bool
-STPathElement::hasMPT() const
+STPathElement::hasMPT() const noexcept
 {
     return isType(STPathElement::TypeMpt);
 }
 
 inline bool
-STPathElement::hasAsset() const
+STPathElement::hasAsset() const noexcept
 {
     return isType(STPathElement::TypeAsset);
 }
 
 inline bool
-STPathElement::isNone() const
+STPathElement::isNone() const noexcept
 {
     return getNodeType() == STPathElement::TypeNone;
 }
@@ -480,13 +492,13 @@ STPathElement::isNone() const
 // Nodes are either an account ID or a offer prefix. Offer prefixs denote a
 // class of offers.
 inline AccountID const&
-STPathElement::getAccountID() const
+STPathElement::getAccountID() const noexcept
 {
     return accountID_;
 }
 
 inline PathAsset const&
-STPathElement::getPathAsset() const
+STPathElement::getPathAsset() const noexcept
 {
     return assetID_;
 }
@@ -504,18 +516,11 @@ STPathElement::getMPTID() const
 }
 
 inline AccountID const&
-STPathElement::getIssuerID() const
+STPathElement::getIssuerID() const noexcept
 {
     return issuerID_;
 }
 
-inline bool
-STPathElement::operator==(STPathElement const& t) const
-{
-    return (type_ & TypeAccount) == (t.type_ & TypeAccount) && hashValue_ == t.hashValue_ &&
-        accountID_ == t.accountID_ && assetID_ == t.assetID_ && issuerID_ == t.issuerID_;
-}
-
 // ------------ STPath ------------
 
 inline STPath::STPath(std::vector<STPathElement> p) : path_(std::move(p))

include/xrpl/protocol/Serializer.h

@@ -596,7 +596,7 @@ template <std::size_t Bits, class Tag>
 BaseUInt<Bits, Tag>
 SerialIter::getBitString()
 {
-    auto const n = Bits / 8;
+    constexpr auto n = BaseUInt<Bits, Tag>::size();
 
     if (remain_ < n)
         Throw<std::runtime_error>("invalid SerialIter getBitString");
@@ -607,7 +607,7 @@ SerialIter::getBitString()
     used_ += n;
     remain_ -= n;
 
-    return BaseUInt<Bits, Tag>::fromVoid(x);
+    return BaseUInt<Bits, Tag>{std::span<std::uint8_t const, n>{x, n}};
 }
 
 }  // namespace xrpl

include/xrpl/protocol/SystemParameters.h

@@ -14,7 +14,7 @@ namespace xrpl {
 // Various protocol and system specific constant globals.
 
 /* The name of the system. */
-static inline std::string const&
+inline std::string const&
 systemName()
 {
     static std::string const kName = "xrpld";
@@ -52,11 +52,10 @@ isLegalAmountSigned(XRPAmount const& amount)
 }
 
 /* The currency code for the native currency. */
-static inline std::string const&
+inline std::string
 systemCurrencyCode()
 {
-    static std::string const kCode = "XRP";
+    return "XRP";
-    return kCode;
 }
 
 /**

include/xrpl/protocol/UintTypes.h

@@ -61,26 +61,40 @@ using Domain = BaseUInt<256>;
 /**
  * XRP currency.
  */
-Currency const&
+constexpr inline Currency const&
-xrpCurrency();
+xrpCurrency() noexcept
+{
+    static constexpr Currency const kCurrency(beast::kZero);
+    return kCurrency;
+}
 
 /**
  * A placeholder for empty currencies.
  */
-Currency const&
+constexpr inline Currency const&
-noCurrency();
+noCurrency() noexcept
+{
+    static constexpr Currency const kCurrency(xrpCurrency().next());
+    return kCurrency;
+}
 
 /**
  * We deliberately disallow the currency that looks like "XRP" because too
  * many people were using it instead of the correct XRP currency.
+ *
+ * Note that this doesn't catch "xRP" or "xrp" or other case variations.
  */
-Currency const&
+constexpr inline Currency const&
-badCurrency();
+badCurrency() noexcept
-
-inline bool
-isXRP(Currency const& c)
 {
-    return c == beast::kZero;
+    static constexpr Currency kCurrency{"0000000000000000000000005852500000000000"};
+    return kCurrency;
+}
+
+constexpr inline bool
+isXRP(Currency const& c) noexcept
+{
+    return c == xrpCurrency();
 }
 
 /**
@@ -98,7 +112,7 @@ to_string(Currency const& c);
  *       to rewrite some unit test code.
  */
 bool
-toCurrency(Currency&, std::string const&);
+toCurrency(Currency&, std::string_view);
 
 /**
  * Tries to convert a string to a Currency, returns noCurrency() on failure.
@@ -107,8 +121,7 @@ toCurrency(Currency&, std::string const&);
  *       unfortunate; changing this will require very careful checking
  *       everywhere and may mean having to rewrite some unit test code.
  */
-Currency
+Currency toCurrency(std::string_view);
-toCurrency(std::string const&);
 
 inline std::ostream&
 operator<<(std::ostream& os, Currency const& x)

include/xrpl/protocol/digest.h

@@ -8,6 +8,7 @@
 #include <array>
 #include <cstddef>
 #include <cstdint>
+#include <span>
 #include <type_traits>
 
 namespace xrpl {
@@ -182,7 +183,7 @@ public:
     operator result_type() noexcept
     {
         auto const digest = Sha512Hasher::result_type(h_);
-        return result_type::fromVoid(digest.data());
+        return result_type{std::span{digest}.first<result_type::size()>()};
     }
 
 private:

include/xrpl/protocol/jss.h

@@ -392,6 +392,7 @@ JSS(max_ledger);                  // in/out: LedgerCleaner
 JSS(max_queue_size);              // out: TxQ
 JSS(max_spend_drops);             // out: AccountInfo
 JSS(max_spend_drops_total);       // out: AccountInfo
+JSS(maximum);
 JSS(mean);                        // out: get_aggregate_price
 JSS(median);                      // out: get_aggregate_price
 JSS(median_fee);                  // out: TxQ

include/xrpl/protocol/nft.h

@@ -8,6 +8,7 @@
 
 #include <cstdint>
 #include <cstring>
+#include <span>
 
 namespace xrpl::nft {
 
@@ -98,7 +99,8 @@ getTaxon(UInt256 const& id)
 inline AccountID
 getIssuer(UInt256 const& id)
 {
-    return AccountID::fromVoid(id.data() + 4);
+    return AccountID{
+        std::span<unsigned char const, uint256::size()>{id}.subspan<4, AccountID::size()>()};
 }
 
 }  // namespace xrpl::nft

include/xrpl/protocol/nftPageMask.h

@@ -2,13 +2,10 @@
 
 #include <xrpl/basics/base_uint.h>
 
-#include <string_view>
-
 namespace xrpl::nft {
 
 // NFT directory pages order their contents based only on the low 96 bits of
 // the NFToken value.  This mask provides easy access to the necessary mask.
-constexpr UInt256 kPageMask(
+constexpr UInt256 kPageMask{"0000000000000000000000000000000000000000ffffffffffffffffffffffff"};
-    std::string_view("0000000000000000000000000000000000000000ffffffffffffffffffffffff"));
 
 }  // namespace xrpl::nft

include/xrpl/tx/ApplyContext.h

@@ -51,7 +51,8 @@ public:
         beast::Journal journal = beast::Journal{beast::Journal::getNullSink()})
         : ApplyContext(registry, base, std::nullopt, tx, preclaimResult, baseFee, flags, journal)
     {
-        XRPL_ASSERT((flags & TapBatch) == 0, "Batch apply flag should not be set");
+        XRPL_ASSERT(
+            (flags & ApplyFlags::Batch) == ApplyFlags::None, "Batch apply flag should not be set");
     }
 
     std::reference_wrapper<ServiceRegistry> registry;

include/xrpl/tx/Transactor.h

@@ -59,10 +59,11 @@ public:
         , parentBatchId(parentBatchId)
         , j(j)
     {
-        XRPL_ASSERT((flags & TapBatch) == TapBatch, "Batch apply flag should be set");
+        XRPL_ASSERT(
+            (flags & ApplyFlags::Batch) == ApplyFlags::Batch, "Batch apply flag should be set");
         XRPL_ASSERT_IF(
-            (flags & TapProposal) != TapNone,
+            (flags & ApplyFlags::Proposal) != ApplyFlags::None,
-            (flags & TapDryRun) != TapNone,
+            (flags & ApplyFlags::DryRun) != ApplyFlags::None,
             "xrpl::PreflightContext : proposal preflight implies dry run");
     }
 
@@ -74,10 +75,11 @@ public:
         beast::Journal j = beast::Journal{beast::Journal::getNullSink()})
         : registry(registry), tx(tx), rules(std::move(rules)), flags(flags), j(j)
     {
-        XRPL_ASSERT((flags & TapBatch) == 0, "Batch apply flag should not be set");
+        XRPL_ASSERT(
+            (flags & ApplyFlags::Batch) == ApplyFlags::None, "Batch apply flag should not be set");
         XRPL_ASSERT_IF(
-            (flags & TapProposal) != TapNone,
+            (flags & ApplyFlags::Proposal) != ApplyFlags::None,
-            (flags & TapDryRun) != TapNone,
+            (flags & ApplyFlags::DryRun) != ApplyFlags::None,
             "xrpl::PreflightContext : proposal preflight implies dry run");
     }
 
@@ -116,7 +118,7 @@ public:
         , j(j)
     {
         XRPL_ASSERT(
-            parentBatchId.has_value() == ((flags & TapBatch) == TapBatch),
+            parentBatchId.has_value() == ((flags & ApplyFlags::Batch) == ApplyFlags::Batch),
             "Parent Batch ID should be set if batch apply flag is set");
     }
 
@@ -129,7 +131,8 @@ public:
         beast::Journal j = beast::Journal{beast::Journal::getNullSink()})
         : PreclaimContext(registry, view, preflightResult, tx, flags, std::nullopt, j)
     {
-        XRPL_ASSERT((flags & TapBatch) == 0, "Batch apply flag should not be set");
+        XRPL_ASSERT(
+            (flags & ApplyFlags::Batch) == ApplyFlags::None, "Batch apply flag should not be set");
     }
 
     PreclaimContext&

include/xrpl/tx/applySteps.h

@@ -41,7 +41,7 @@ struct ApplyResult
 inline bool
 isTecClaimHardFail(TER ter, ApplyFlags flags)
 {
-    return isTecClaim(ter) && ((flags & TapRetry) == 0u);
+    return isTecClaim(ter) && ((flags & ApplyFlags::Retry) == ApplyFlags::None);
 }
 
 /**

nix/check-tools/macos.txt

@@ -2,144 +2,144 @@ Detected OS: macos (Darwin arm64)
 
 Core build tools:
   ✅ cmake
-     cmake version 4.1.2
+     cmake version 4.4.3
-     /nix/store/gvabsb4yqb5xsqzqph54rijnn4zpihnp-cmake-4.1.2/bin/cmake
+     /nix/store/q85csxf4s4shx89zif097h1ql4ax1rrz-cmake-4.4.3/bin/cmake
   ✅ conan
-     Conan version 2.28.1
+     Conan version 2.32.0
-     /nix/store/9jiyxmkpwmn6dcqs0765s83riw3l5ail-conan-2.28.1/bin/conan
+     /nix/store/921jqsgbilixmr3xchj95si0jl8pi13z-conan-2.32.0/bin/conan
   ✅ git
-     git version 2.54.0
+     git version 2.55.0
-     /nix/store/a14yxcqvv9x2l9mllgpirzhvz93pgprg-git-2.54.0/bin/git
+     /nix/store/gw7c7m0dwca5lg4152x9lpmxpj171bzw-git-2.55.0/bin/git
   ✅ python3
-     Python 3.13.13
+     Python 3.14.7
-     /nix/store/ygxqin6ydzjfawywqpp5pal8wv6sf5bh-python3-3.13.13/bin/python3.13
+     /nix/store/0kcws5blwbdyxqxjd1w8hjipz61xny3k-python3-3.14.7/bin/python3.14
 
 Development tooling:
   ✅ ccache
      ccache version 4.13.6
-     /nix/store/57davyvs6p6dkrl3svzwg1ph18wsy4cz-ccache-4.13.6/bin/ccache
+     /nix/store/ydr5nlzxp1djb5256y0zzqa87vz55gsk-ccache-4.13.6/bin/ccache
   ✅ clang
-     clang version 22.1.7
+     clang version 22.1.8
-     /nix/store/192glrb2cldvziyf3378mzjqbzx3ih4g-clang-wrapper-22.1.7/bin/clang
+     /nix/store/dakcxgwz4ixkk6ps50b7vn3dvblyzsnf-clang-wrapper-22.1.8/bin/clang
   ✅ clang-22
-     clang version 22.1.7
+     clang version 22.1.8
-     /nix/store/rbap7zqq7mw00fyqa02p5rj7gqjp4w5i-clang-22/bin/clang-22
+     /nix/store/w826sqb98nnym6kzackg829664iqdlxj-clang-22/bin/clang-22
   ✅ clang++
-     clang version 22.1.7
+     clang version 22.1.8
-     /nix/store/192glrb2cldvziyf3378mzjqbzx3ih4g-clang-wrapper-22.1.7/bin/clang++
+     /nix/store/dakcxgwz4ixkk6ps50b7vn3dvblyzsnf-clang-wrapper-22.1.8/bin/clang++
   ✅ clang++-22
-     clang version 22.1.7
+     clang version 22.1.8
-     /nix/store/v9haf787f7bcz0mq1sad4bpyx21pj6li-clang++-22/bin/clang++-22
+     /nix/store/wnwyw3yfqrhpxij65bl3pa1x65q2zg3m-clang++-22/bin/clang++-22
   ✅ ClangBuildAnalyzer
      ClangBuildAnalyzer 1.6.0
-     /nix/store/4l50ds9fa2mkvh7wg8qzrlbmjs12sb8l-clangbuildanalyzer-1.6.0/bin/ClangBuildAnalyzer
+     /nix/store/c7jjnw29ra78jdlzjww2m374izhy05n8-clangbuildanalyzer-1.6.0/bin/ClangBuildAnalyzer
   ✅ curl
-     curl 8.20.0 (aarch64-apple-darwin25.3.0) libcurl/8.20.0 OpenSSL/3.6.2 zlib/1.3.2 libssh2/1.11.1 nghttp2/1.69.0 mit-krb5/1.22.1
+     curl 8.22.0 (aarch64-apple-darwin25.6.0) libcurl/8.22.0 OpenSSL/3.5.8 zlib/1.3.2 libssh2/1.11.1 nghttp2/1.70.0 mit-krb5/1.22.2
-     /nix/store/kclq0czaxvsgh4ym9ld7b6iwy50l1snk-curl-8.20.0-bin/bin/curl
+     /nix/store/pq1h17abqy6q5y6k5dn9qj0fwb89flba-curl-8.22.0-bin/bin/curl
   ✅ file
-     file-5.47
+     file-5.48
-     /nix/store/dax63li7wwcbqxxkkgzc4g2rx7d4w86x-file-5.47/bin/file
+     /nix/store/y44vpziwbzfm8020dzlqqbybyyy7lb6g-file-5.48/bin/file
   ✅ less
-     less 692 (PCRE2 regular expressions)
+     less 710 (PCRE2 regular expressions)
-     /nix/store/lvr16y75r1pdxpdv0aph5ak2yd0hkvqm-less-692/bin/less
+     /nix/store/3yn3dx5fwg5i0inqqzwnxq7f6lwhpjqa-less-710/bin/less
   ✅ make
      GNU Make 4.4.1
-     /nix/store/8wwiw8pwyhrkzyq28hqzxfl4z84lks81-gnumake-4.4.1/bin/make
+     /nix/store/8l4wgxmhdxfvc9g18y76bnxl1ghgcp7n-gnumake-4.4.1/bin/make
   ✅ netstat
      present
-     /nix/store/qsd1kzqb0ahrk433vmyl245gp623j19s-network_cmds-730.80.3/bin/netstat
+     /nix/store/57fqvgdav8lrmzndkwm7qrgksl01yj23-network_cmds-741.100.2/bin/netstat
   ✅ ninja
      1.13.2
-     /nix/store/bqykhrblarkj4fl0hz2mf8ngwfv6x6bz-ninja-1.13.2/bin/ninja
+     /nix/store/infm4vlx71q83bqz0k559w1gn4b0rq4i-ninja-1.13.2/bin/ninja
   ✅ perl
-     v5.42.0
+     v5.42.3
-     /nix/store/js13ri9fvm0ajk1fpd3acigys2a9whdv-perl-5.42.0/bin/perl
+     /nix/store/7rvr6qjfzk2ybzn1imjw6c6qq1n1a9cr-perl-5.42.3/bin/perl
   ✅ pkg-config
      0.29.2
-     /nix/store/lzrwr375jqhhbca116kja96xf1md83l8-pkg-config-wrapper-0.29.2/bin/pkg-config
+     /nix/store/nhgylvj98klqggy54h7gbc3b2ia4a00y-pkg-config-wrapper-0.29.2/bin/pkg-config
   ✅ vim
      VIM - Vi IMproved 9.2 (2026 Feb 14, compiled Jan 01 1980 00:00:00)
-     /nix/store/6vbkykg92w603c0sw3mkk7p7mfaawbns-vim-9.2.0389/bin/vim
+     /nix/store/akaa9kqm3b8rlkv61kvsqr2l2j70rvxb-vim-9.2.1001/bin/vim
   ✅ zip
      Zip 3.0
-     /nix/store/z6ph729vcakbvz3wh8ln1wk6mi06w487-zip-3.0/bin/zip
+     /nix/store/dvawr36npnad4xa6dxi2ss0fw44aa82r-zip-3.0/bin/zip
   ✅ clang-apply-replacements
-     clang-apply-replacements version 22.1.7
+     clang-apply-replacements version 22.1.8
-     /nix/store/vzyyjf3cm1hbj9wcr2qcb66x6j98zpy7-clang-tools-22.1.7/bin/clang-apply-replacements
+     /nix/store/5bij4zn161lagwyndmrr21vmxjg054nv-clang-tools-22.1.8/bin/clang-apply-replacements
   ✅ clang-apply-replacements-22
-     clang-apply-replacements version 22.1.7
+     clang-apply-replacements version 22.1.8
-     /nix/store/m3ii69rca4077lf4wlk7m3jcag1fs577-clang-apply-replacements-22/bin/clang-apply-replacements-22
+     /nix/store/w4bz034k4l0w719rrmbwnqcgyjbswy81-clang-apply-replacements-22/bin/clang-apply-replacements-22
   ✅ clang-format
-     clang-format version 22.1.7
+     clang-format version 22.1.8
-     /nix/store/vzyyjf3cm1hbj9wcr2qcb66x6j98zpy7-clang-tools-22.1.7/bin/clang-format
+     /nix/store/5bij4zn161lagwyndmrr21vmxjg054nv-clang-tools-22.1.8/bin/clang-format
   ✅ clang-format-22
-     clang-format version 22.1.7
+     clang-format version 22.1.8
-     /nix/store/4fawqy6ngqcsqd2ygyyzm93q0xy3f5gs-clang-format-22/bin/clang-format-22
+     /nix/store/w7z346l0r8y36b6lc5i7jzj3w0581l2y-clang-format-22/bin/clang-format-22
   ✅ clang-tidy
-     LLVM version 22.1.7
+     LLVM version 22.1.8
-     /nix/store/vzyyjf3cm1hbj9wcr2qcb66x6j98zpy7-clang-tools-22.1.7/bin/clang-tidy
+     /nix/store/5bij4zn161lagwyndmrr21vmxjg054nv-clang-tools-22.1.8/bin/clang-tidy
   ✅ clang-tidy-22
-     LLVM version 22.1.7
+     LLVM version 22.1.8
-     /nix/store/jqw4280saixaxxihwdba9ldm2fsm6dr3-clang-tidy-22/bin/clang-tidy-22
+     /nix/store/0lv25qd3ddgjm3ndn70q61jfr6krlkl7-clang-tidy-22/bin/clang-tidy-22
   ✅ dot
-     dot - graphviz version 12.2.1 (0)
+     dot - graphviz version 15.1.1 (0)
-     /nix/store/ijb4fbnqa6wzlpqnhb6q9knqpf7qqn5z-graphviz-12.2.1/bin/dot
+     /nix/store/mc99a6bpbk2waym2cnw6ifmxli4ndb4x-graphviz-15.1.1/bin/dot
   ✅ doxygen
-     1.16.1
+     1.17.0
-     /nix/store/kbryjdpq9jizjb0ws0nzbf2h2ymbdiwm-doxygen-1.16.1/bin/doxygen
+     /nix/store/kz43yaj0wg6fx6cbrcmi2442z1ramy0c-doxygen-1.17.0/bin/doxygen
   ✅ gcovr
      gcovr 8.4
-     /nix/store/wn8jiyh9p0bybs96s4163qp3k8vfmczx-python3.13-gcovr-8.4/bin/gcovr
+     /nix/store/czj1vxsizrbba280gg22cys40qxkqjgr-python3.14-gcovr-8.4/bin/gcovr
   ✅ gh
-     gh version 2.94.0 (nixpkgs)
+     gh version 2.102.0 (2026-09-30)
-     /nix/store/fhnpw0hs0gjms1ha6ap02jq7rx13gkbp-gh-2.94.0/bin/gh
+     /nix/store/s8bahl6zssvry93ihivfmk1l6c58byrr-gh-2.102.0/bin/gh
   ✅ git-cliff
-     git-cliff 2.13.1
+     git-cliff 2.14.2
-     /nix/store/cy0wwhgxa7yvrz97zydbq6sqmixc90fq-git-cliff-2.13.1/bin/git-cliff
+     /nix/store/k4m5yk0qb7hfslwsq1zjajz1d94j12bj-git-cliff-2.14.2/bin/git-cliff
   ✅ git-lfs
-     git-lfs/3.7.1 (3.7.1; darwin arm64; go 1.26.3)
+     git-lfs/3.8.0 (3.8.0; darwin arm64; go 1.26.8)
-     /nix/store/k9r7zjfjplqa4d5s71cqvf2iv73jd9mc-git-lfs-3.7.1/bin/git-lfs
+     /nix/store/wzixjr3yb40a13m2q654hm3bdjn6sal3-git-lfs-3.8.0/bin/git-lfs
   ✅ gpg
      gpg (GnuPG) 2.4.9
-     /nix/store/cgh6iwzz5jgx9z5whka4vgj210i6npc6-gnupg-2.4.9/bin/gpg
+     /nix/store/0ldfwnwx385i5kh7cyvxx4mkvgjhs5rh-gnupg-2.4.9/bin/gpg
   ✅ pre-commit
-     pre-commit 4.5.1
+     pre-commit 4.6.2
-     /nix/store/z3cca68620w0w10f090szgzdnmh1waf2-pre-commit-4.5.1/bin/pre-commit
+     /nix/store/ivh54xypg9qvd3ha9lis0i8p4nkf8n7a-pre-commit-4.6.2/bin/pre-commit
   ✅ run-clang-tidy
      usage: run-clang-tidy [-h] [-allow-enabling-alpha-checkers]
-     /nix/store/4x28x911z2f9y7adqlh3qspp4a16dig7-run-clang-tidy/bin/run-clang-tidy
+     /nix/store/3xss1mm3mh1hzcmg182na6ki1p5rnxf1-run-clang-tidy/bin/run-clang-tidy
   ✅ run-clang-tidy-22
      usage: run-clang-tidy [-h] [-allow-enabling-alpha-checkers]
-     /nix/store/x8iymrh76sk5q91ryg5pa7i32s6gfh34-run-clang-tidy-22/bin/run-clang-tidy-22
+     /nix/store/w68r9z07hcq4fwbfyq3yvc7qxm8aqfbl-run-clang-tidy-22/bin/run-clang-tidy-22
 
 Rust toolchain:
   ✅ cargo
      cargo 1.97.1 (c980f4866 2026-06-30)
-     /nix/store/bnfk1sl4s9angb0vj1cj9a5y5zvqinwy-rust-minimal-1.97.1/bin/cargo
+     /nix/store/gklji8yq8yrx1k039c10kwz60vqf2dxj-rust-minimal-1.97.1/bin/cargo
   ✅ cargo-audit
-     cargo-audit-audit 0.22.1
+     cargo-audit-audit 0.22.2
-     /nix/store/snwkga2f5gyf404h7mmp9wriwxb8v65f-cargo-audit-0.22.1/bin/cargo-audit
+     /nix/store/7jgrwj557l91940aj0ag4i924ima1cqn-cargo-audit-0.22.2/bin/cargo-audit
   ✅ cargo-llvm-cov
-     cargo-llvm-cov 0.8.5
+     cargo-llvm-cov 0.9.0
-     /nix/store/fpiqdh91gwyxalqp409ynm0s0g086w7w-cargo-llvm-cov-0.8.5/bin/cargo-llvm-cov
+     /nix/store/5q1h285z8zzkw2qxig9a0b1avcsk1cf0-cargo-llvm-cov-0.9.0/bin/cargo-llvm-cov
   ✅ cargo-nextest
-     cargo-nextest 0.9.137
+     cargo-nextest 0.9.146
-     /nix/store/ylz7m947mhkgsp6i7611id3s3gcd58nq-cargo-nextest-0.9.137/bin/cargo-nextest
+     /nix/store/69v3hx3k597hcxd2zy7yad7fg0aw5yxd-cargo-nextest-0.9.146/bin/cargo-nextest
   ✅ clippy-driver
      clippy 0.1.97 (8bab26f4f6 2026-07-14)
-     /nix/store/bnfk1sl4s9angb0vj1cj9a5y5zvqinwy-rust-minimal-1.97.1/bin/clippy-driver
+     /nix/store/gklji8yq8yrx1k039c10kwz60vqf2dxj-rust-minimal-1.97.1/bin/clippy-driver
   ✅ rust-analyzer
      rust-analyzer 1.97.1 (8bab26f4 2026-07-14)
-     /nix/store/j6apc5pmd0giy15da9p650r8zklslmvi-rust-analyzer-preview-1.97.1-aarch64-apple-darwin/bin/rust-analyzer
+     /nix/store/30rbyk8gx7v53fxqhs4pp0fvxfjycspr-rust-analyzer-preview-1.97.1-aarch64-apple-darwin/bin/rust-analyzer
   ✅ rust-nightly
-     rustc 1.99.0-nightly (87e5904f5 2026-07-20)
+     rustc 1.101.0-nightly (282215592 2026-10-04)
-     /nix/store/fqpjz4l0nsnji8b2pz57mnj0akbp6hcl-rust-nightly/bin/rust-nightly
+     /nix/store/a9552rf3pylcnkijc1z0hf1lcnv50djq-rust-nightly/bin/rust-nightly
   ✅ rustc
      rustc 1.97.1 (8bab26f4f 2026-07-14)
-     /nix/store/bnfk1sl4s9angb0vj1cj9a5y5zvqinwy-rust-minimal-1.97.1/bin/rustc
+     /nix/store/gklji8yq8yrx1k039c10kwz60vqf2dxj-rust-minimal-1.97.1/bin/rustc
   ✅ rustfmt
      rustfmt 1.9.0-stable (8bab26f4f6 2026-07-14)
-     /nix/store/5ymwgr9jqjz7zzbmj0j5vqbwcd3kp0vm-rustfmt-preview-1.97.1-aarch64-apple-darwin/bin/rustfmt
+     /nix/store/0jmdipyn8266j9kqx2xxm2qkxlrlrjfc-rustfmt-preview-1.97.1-aarch64-apple-darwin/bin/rustfmt
 
 Skipping git-over-HTTPS check (CHECK_TOOLS_SKIP_CLONE is set).
 

nix/ci-env.nix

@@ -21,7 +21,8 @@ let
     )
   );
 
-  toolchain = if pkgs.stdenv.isLinux then linux.toolchain else (darwin.toolchain ++ [ darwinEnv ]);
+  toolchain =
+    if pkgs.stdenv.hostPlatform.isLinux then linux.toolchain else (darwin.toolchain ++ [ darwinEnv ]);
 in
 {
   default = pkgs.buildEnv {

nix/devshell.nix

@@ -20,15 +20,16 @@ let
 
   # Custom-glibc stdenvs, matching the CI environment. darwin has no custom
   # glibc, so there they fall back to the plain nixpkgs stdenvs.
-  customGccStdenv = if pkgs.stdenv.isLinux then linux.gccStdenv else plainGccStdenv;
+  customGccStdenv = if pkgs.stdenv.hostPlatform.isLinux then linux.gccStdenv else plainGccStdenv;
-  customClangStdenv = if pkgs.stdenv.isLinux then linux.clangStdenv else plainClangStdenv;
+  customClangStdenv =
+    if pkgs.stdenv.hostPlatform.isLinux then linux.clangStdenv else plainClangStdenv;
 
   # gcov matching each gcc shell, so `-Dcoverage=ON` builds work in the shell.
   plainGcov = mkGcov {
     name = "plain";
     cc = gccPackage.cc;
   };
-  customGccGcov = if pkgs.stdenv.isLinux then linux.gcov else plainGcov;
+  customGccGcov = if pkgs.stdenv.hostPlatform.isLinux then linux.gcov else plainGcov;
 
   # Whole directory: init.sh locates the profiles relative to itself.
   conanDir = ../conan;
@@ -51,7 +52,7 @@ let
 
   # Not sdkEnv: a shell's stdenv already sets that up. Prepended so the stub
   # beats the nixpkgs libresolv this shell's tooling drags in.
-  darwinLibresolvHook = pkgs.lib.optionalString pkgs.stdenv.isDarwin (
+  darwinLibresolvHook = pkgs.lib.optionalString pkgs.stdenv.hostPlatform.isDarwin (
     pkgs.lib.concatLines (
       pkgs.lib.mapAttrsToList (
         name: value: ''export ${name}="${value} ''${${name}:-}"''
@@ -126,7 +127,7 @@ let
 in
 rec {
   # macOS: Nix Clang. Linux: Nix GCC.
-  default = if pkgs.stdenv.isDarwin then clang else gcc;
+  default = if pkgs.stdenv.hostPlatform.isDarwin then clang else gcc;
 
   # gcc/clang use the custom-glibc toolchain, matching CI. On darwin there is no
   # custom glibc, so they fall back to the plain nixpkgs toolchain.
@@ -171,7 +172,7 @@ rec {
 # The *-plain shells (stock nixpkgs toolchain) exist only on Linux: on darwin
 # gcc/clang are already plain, so these would be redundant and are omitted, which
 # makes `nix develop .#gcc-plain` fail there rather than silently aliasing gcc.
-// pkgs.lib.optionalAttrs pkgs.stdenv.isLinux {
+// pkgs.lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux {
   gcc-plain = makeShell {
     shellName = "gcc-plain";
     stdenv = plainGccStdenv;

src/libxrpl/basics/CountedObject.cpp

@@ -1,39 +0,0 @@
-#include <xrpl/basics/CountedObject.h>
-
-#include <algorithm>
-
-namespace xrpl {
-
-CountedObjects&
-CountedObjects::getInstance() noexcept
-{
-    static CountedObjects kInstance;
-
-    return kInstance;
-}
-
-CountedObjects::CountedObjects() noexcept : count_(0), head_(nullptr)
-{
-}
-
-CountedObjects::List
-CountedObjects::getCounts(int minimumThreshold) const
-{
-    List counts;
-
-    // When other operations are concurrent, the count
-    // might be temporarily less than the actual count.
-    counts.reserve(count_.load());
-
-    for (auto* ctr = head_.load(); ctr != nullptr; ctr = ctr->getNext())
-    {
-        if (ctr->getCount() >= minimumThreshold)
-            counts.emplace_back(ctr->getName(), ctr->getCount());
-    }
-
-    std::ranges::sort(counts);
-
-    return counts;
-}
-
-}  // namespace xrpl

src/libxrpl/ledger/BookDirs.cpp

@@ -80,10 +80,10 @@ BookDirs::const_iterator::operator++()
     XRPL_ASSERT(index_ != kZero, "xrpl::BookDirs::const_iterator::operator++ : nonzero index");
     if (!cdirNext(*view_, curKey_, sle_, entry_, index_))
     {
-        if (index_ == 0)
+        if (index_ == kZero)
             curKey_ = view_->succ(++curKey_, nextQuality_).value_or(kZero);
 
-        if (index_ != 0 || curKey_ == kZero)
+        if (index_ != kZero || curKey_ == kZero)
         {
             curKey_ = key_;
             entry_ = 0;

src/libxrpl/ledger/Ledger.cpp

@@ -11,6 +11,7 @@
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/ledger/LedgerTiming.h>
 #include <xrpl/ledger/ReadView.h>
+#include <xrpl/ledger/entries/FeeSettingsEntry.h>
 #include <xrpl/nodestore/NodeObject.h>
 #include <xrpl/protocol/Feature.h>
 #include <xrpl/protocol/Fees.h>
@@ -261,7 +262,7 @@ Ledger::Ledger(Ledger const& prevLedger, NetClock::time_point closeTime)
 {
     header_.seq = prevLedger.header_.seq + 1;
     header_.parentCloseTime = prevLedger.header_.closeTime;
-    header_.hash = prevLedger.header().hash + UInt256(1);
+    header_.hash = prevLedger.header().hash.next();
     header_.drops = prevLedger.header().drops;
     header_.closeTimeResolution = prevLedger.header_.closeTimeResolution;
     header_.parentHash = prevLedger.header().hash;
@@ -560,7 +561,7 @@ Ledger::setup()
 
     try
     {
-        if (auto const sle = read(keylet::feeSettings()))
+        if (auto const sle = FeeSettingsEntryR(*this))
         {
             bool oldFees = false;
             bool newFees = false;

src/libxrpl/ledger/View.cpp

@@ -9,6 +9,7 @@
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
+#include <xrpl/ledger/entries/LedgerHashesEntry.h>
 #include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/CredentialHelpers.h>
 #include <xrpl/ledger/helpers/DirectoryHelpers.h>
@@ -361,17 +362,16 @@ hashOfSeq(ReadView const& ledger, LedgerIndex seq, beast::Journal journal)
     if (int const diff = ledger.seq() - seq; diff <= 256)
     {
         // Within 256...
-        auto const hashIndex = ledger.read(keylet::skip());
+        LedgerHashesEntryR const hashIndex(ledger, journal);
         if (hashIndex)
         {
             XRPL_ASSERT(
                 hashIndex->getFieldU32(sfLastLedgerSequence) == (ledger.seq() - 1),
                 "xrpl::hashOfSeq : matching ledger sequence");
-            STVector256 vec = hashIndex->getFieldV256(sfHashes);
+            if (auto const hash = hashIndex.hashAt(diff - 1))
-            if (vec.size() >= diff)
+                return hash;
-                return vec[vec.size() - diff];
             JLOG(journal.warn()) << "Ledger " << ledger.seq() << " missing hash for " << seq << " ("
-                                 << vec.size() << "," << diff << ")";
+                                 << hashIndex->getFieldV256(sfHashes).size() << "," << diff << ")";
         }
         else
         {
@@ -387,16 +387,14 @@ hashOfSeq(ReadView const& ledger, LedgerIndex seq, beast::Journal journal)
     }
 
     // in skiplist
-    auto const hashIndex = ledger.read(keylet::skip(seq));
+    LedgerHashesEntryR const hashIndex(keylet::skip(seq), ledger, journal);
     if (hashIndex)
     {
         auto const lastSeq = hashIndex->getFieldU32(sfLastLedgerSequence);
         XRPL_ASSERT(lastSeq >= seq, "xrpl::hashOfSeq : minimum last ledger");
         XRPL_ASSERT((lastSeq & 0xff) == 0, "xrpl::hashOfSeq : valid last ledger");
-        auto const diff = (lastSeq - seq) >> 8;
+        if (auto const hash = hashIndex.hashAt((lastSeq - seq) >> 8))
-        STVector256 vec = hashIndex->getFieldV256(sfHashes);
+            return hash;
-        if (vec.size() > diff)
-            return vec[vec.size() - diff - 1];
     }
     JLOG(journal.warn()) << "Can't get seq " << seq << " from " << ledger.seq() << " error";
     return std::nullopt;

src/libxrpl/ledger/helpers/AccountRootHelpers.cpp

@@ -506,7 +506,7 @@ pseudoAccountAddress(ReadView const& view, UInt256 const& pseudoOwnerKey)
         RipeshaHasher rsh;
         auto const hash = sha512Half(i, view.header().parentHash, pseudoOwnerKey);
         rsh(hash.data(), hash.size());
-        AccountID const ret = AccountID::fromRaw(static_cast<RipeshaHasher::result_type>(rsh));
+        AccountID const ret{static_cast<RipeshaHasher::result_type>(rsh)};
         if (!view.read(keylet::account(ret)))
             return ret;
     }

src/libxrpl/nodestore/DecodedBlob.cpp

@@ -1,7 +1,6 @@
 #include <xrpl/nodestore/detail/DecodedBlob.h>
 
 #include <xrpl/basics/Blob.h>
-#include <xrpl/basics/base_uint.h>
 #include <xrpl/basics/safe_cast.h>
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/nodestore/NodeObject.h>
@@ -12,8 +11,13 @@
 
 namespace xrpl::node_store {
 
-DecodedBlob::DecodedBlob(void const* key, void const* value, int valueBytes) : key_(key)
+DecodedBlob::DecodedBlob(std::optional<UInt256> key, void const* value, int valueBytes)
 {
+    if (!key)
+        return;
+
+    key_ = key.value();
+
     /*  Data format:
 
         Bytes
@@ -63,7 +67,7 @@ DecodedBlob::createObject()
     {
         Blob data(objectData_, objectData_ + dataBytes_);
 
-        object = NodeObject::createObject(objectType_, std::move(data), UInt256::fromVoid(key_));
+        object = NodeObject::createObject(objectType_, std::move(data), key_);
     }
 
     return object;

src/libxrpl/nodestore/backend/NuDBFactory.cpp

@@ -38,6 +38,7 @@
 #include <functional>
 #include <memory>
 #include <optional>
+#include <span>
 #include <sstream>
 #include <stdexcept>
 #include <string>
@@ -216,7 +217,7 @@ public:
             [&hash, pno, &status](void const* data, std::size_t size) {
                 nudb::detail::buffer bf;
                 auto const result = nodeobjectDecompress(data, size, bf);
-                DecodedBlob decoded(hash.data(), result.first, result.second);
+                DecodedBlob decoded(hash, result.first, result.second);
                 if (!decoded.wasOk())
                 {
                     status = Status::DataCorrupt;
@@ -240,7 +241,7 @@ public:
         nudb::error_code ec;
         nudb::detail::buffer bf;
         auto const result = nodeobjectCompress(e.getData(), e.getSize(), bf);
-        db.insert(e.getKey(), result.first, result.second, ec);
+        db.insert(e.getKey().data(), result.first, result.second, ec);
         if (ec && ec != nudb::error::key_exists)
             Throw<nudb::system_error>(ec);
     }
@@ -288,14 +289,25 @@ public:
             Throw<nudb::system_error>(ec);
         nudb::visit(
             dp,
-            [&](void const* key,
+            [&](void const* keyData,
                 std::size_t keyBytes,
                 void const* data,
                 std::size_t size,
                 nudb::error_code&) {
+                auto key = uint256::fromRaw(
+                    std::span{static_cast<unsigned char const*>(keyData), keyBytes});
+
+                if (!key) [[unlikely]]
+                {
+                    ec = make_error_code(nudb::error::invalid_key_size);
+                    return;
+                }
+
                 nudb::detail::buffer bf;
                 auto const result = nodeobjectDecompress(data, size, bf);
+
                 DecodedBlob decoded(key, result.first, result.second);
+
                 if (!decoded.wasOk())
                 {
                     ec = make_error_code(nudb::error::missing_value);

src/libxrpl/nodestore/backend/RocksDBFactory.cpp

@@ -38,6 +38,7 @@
 #include <format>
 #include <functional>
 #include <memory>
+#include <span>
 #include <stdexcept>
 #include <string>
 
@@ -111,6 +112,9 @@ public:
         if (!getIfExists(keyValues, Keys::kPath, name))
             Throw<std::runtime_error>("Missing path in RocksDBFactory backend");
 
+        if (keyBytes != uint256::size())
+            Throw<std::runtime_error>("Incorrect key size: expected 32 bytes");
+
         rocksdb::BlockBasedTableOptions tableOptions;
         options.env = env;
 
@@ -292,7 +296,7 @@ public:
 
         if (getStatus.ok())
         {
-            DecodedBlob decoded(hash.data(), string.data(), string.size());
+            DecodedBlob decoded(hash, string.data(), string.size());
 
             if (decoded.wasOk())
             {
@@ -317,8 +321,8 @@ public:
             }
             else
             {
-                status = static_cast<Status>(
+                status = checkedCast<Status>(
-                    static_cast<int>(Status::CustomCode) + unsafeCast<int>(getStatus.code()));
+                    safeCast<int>(Status::CustomCode) + safeCast<int>(getStatus.code()));
 
                 JLOG(journal.error()) << getStatus.ToString();
             }
@@ -347,7 +351,7 @@ public:
             EncodedBlob const encoded(e);
 
             wb.Put(
-                rocksdb::Slice(reinterpret_cast<char const*>(encoded.getKey()), keyBytes),
+                rocksdb::Slice(reinterpret_cast<char const*>(encoded.getKey().data()), keyBytes),
                 rocksdb::Slice(
                     reinterpret_cast<char const*>(encoded.getData()), encoded.getSize()));
         }
@@ -375,9 +379,12 @@ public:
 
         for (it->SeekToFirst(); it->Valid(); it->Next())
         {
-            if (it->key().size() == keyBytes)
+            if (it->key().size() == keyBytes && it->key().size() == uint256::size())
             {
-                DecodedBlob decoded(it->key().data(), it->value().data(), it->value().size());
+                DecodedBlob decoded(
+                    uint256::fromRaw(std::span{it->key().data(), it->key().size()}),
+                    it->value().data(),
+                    it->value().size());
 
                 if (decoded.wasOk())
                 {

src/libxrpl/protocol/AccountID.cpp

@@ -8,6 +8,8 @@
 #include <xrpl/protocol/digest.h>
 #include <xrpl/protocol/tokens.h>
 
+#include <algorithm>
+#include <array>
 #include <atomic>
 #include <cstdint>
 #include <cstring>
@@ -19,95 +21,143 @@
 
 namespace xrpl {
 
-namespace detail {
+namespace {
 
-/**
+/** If true, we implement a cache for account ID lookups.
- * Caches the base58 representations of AccountIDs
+
+    This is generally a good idea and can improve performance, especially
+    when serving client requests.
+
+    The cache may generate warnings under some sanitizers; if you want to
+    disable caching, set this variable to false.
  */
-class AccountIdCache
+constexpr bool cacheAccountIDs = true;
+
+/** Represents a cached entry for the given AccountID.
+
+    We keep the size and alignment of the structure at 64 bytes to
+    make sure it fits within a cache line and avoid false sharing.
+ */
+struct alignas(64) CachedAccountID
 {
-private:
+    /** The sequence lock for the entry.
-    struct CachedAccountID
-    {
-        AccountID id;
-        char encoding[40] = {0};
-    };
 
-    // The actual cache
+        An even value means that the data is stable, whereas an odd
-    std::vector<CachedAccountID> cache_;
+        value indicates the data is being actively modified.
 
-    // We use a hash function designed to resist algorithmic complexity attacks
+        We use a 32-bit value to ensure that the counter will never
-    HardenedHash<> hasher_;
+        return to an observed value during a read window.
+     */
+    std::atomic<std::uint32_t> seq{0};
 
-    // 64 spinlocks, packed into a single 64-bit value
+    /** The account id. */
-    std::atomic<std::uint64_t> locks_ = 0;
+    AccountID id{};
 
-public:
+    /** The length of the cached encoding.
-    AccountIdCache(std::size_t count) : cache_(count)
-    {
-        // This is non-binding, but we try to avoid wasting memory that
-        // is caused by overallocation.
-        cache_.shrink_to_fit();
-    }
 
-    std::string
+        This field disambiguates collisions between ACCOUNT_ZERO and
-    toBase58(AccountID const& id)
+        never-written-to slots, since they would otherwise share the
-    {
+        same encoded bits.
-        auto const index = hasher_(id) % cache_.size();
+     */
+    std::uint8_t len = 0;
 
-        PackedSpinlock sl(locks_, index % 64);
+    /** The actual string encoding. */
-
+    char encoding[39] = {0};
-        {
-            std::scoped_lock const lock(sl);
-
-            // The check against the first character of the encoding ensures
-            // that we don't mishandle the case of the all-zero account:
-            if (cache_[index].encoding[0] != 0 && cache_[index].id == id)
-                return cache_[index].encoding;
-        }
-
-        auto ret = encodeBase58Token(TokenType::AccountID, id.data(), id.size());
-
-        XRPL_ASSERT(ret.size() <= 38, "xrpl::detail::AccountIdCache : maximum result size");
-
-        {
-            std::scoped_lock const lock(sl);
-            cache_[index].id = id;
-            std::strcpy(cache_[index].encoding, ret.c_str());
-        }
-
-        return ret;
-    }
 };
 
-}  // namespace detail
+static_assert(sizeof(CachedAccountID) == 64 && alignof(CachedAccountID) == 64);
 
-static std::unique_ptr<detail::AccountIdCache> gAccountIdCache;
+// The actual cache to use: a simple, direct-mapped, best-effort construct.
+//
+// We do not use a hardened hash for this because an AccountID is already
+// just cryptographically generated (i.e. uniformly distributed) bits and
+// there is no amplification, since collisions do not carry an additional
+// cost.
+//
+// The size is a "nice" power of 2 because it makes the calculation of an
+// index easier.
+constinit std::array<CachedAccountID, 65536> gAccountIdCache{};
 
-void
+}  // namespace
-initAccountIdCache(std::size_t count)
-{
-    if (!gAccountIdCache && count != 0)
-        gAccountIdCache = std::make_unique<detail::AccountIdCache>(count);
-}
 
 std::string
 toBase58(AccountID const& v)
 {
-    if (gAccountIdCache)
+    // Since the input bits are generated by a cryptographically secure
-        return gAccountIdCache->toBase58(v);
+    // hash construct, we can just pick any subset of them, no muss, no
+    // fuss.
+    auto const index = [&v]() -> std::uint16_t {
+        auto const data = v.data();
 
-    return encodeBase58Token(TokenType::AccountID, v.data(), v.size());
+        return static_cast<std::uint16_t>(data[0]) | (static_cast<std::uint16_t>(data[1]) << 8);
+    }();
+
+    if constexpr (cacheAccountIDs)
+    {
+        auto& slot = gAccountIdCache[index];
+
+        // This is the optimistic, store-free read path: a collision with a
+        // concurrent writer will be detected because the seq recheck fails
+        // and we fall through to the slow path.
+        //
+        // These unsynchronized reads of the slot fields are, formally, data
+        // races and, technically speaking, result in undefined behavior and
+        // a tool like TSAN might flag them. These should not have an impact
+        // on the correctness of the returned data: the sequence lock checks
+        // ensure we discard any data that was in flux.
+        if (auto const s0 = slot.seq.load(std::memory_order::acquire);
+            (s0 & 1) == 0 && slot.len != 0 && slot.id == v)
+        {
+            char buf[38];
+            auto const len = std::min<std::size_t>(slot.len, sizeof(buf));
+            std::memcpy(buf, slot.encoding, len);
+
+            // Prevents the loads above from sinking below the recheck; the
+            // acquire on s0 constrains later operations, not earlier ones.
+            std::atomic_thread_fence(std::memory_order::acquire);
+
+            // Everything read from the slot — the gates above and the bytes in
+            // buf — precedes this recheck and is validated by it. No slot access
+            // may follow it.
+            if (slot.seq.load(std::memory_order::relaxed) == s0)
+                return std::string(buf, len);
+        }
+    }
+
+    auto ret = encodeBase58Token(TokenType::AccountID, v.data(), v.size());
+
+    XRPL_ASSERT(!ret.empty() && ret.size() <= 38, "xrpl::toBase58 : maximum result size");
+
+    if constexpr (cacheAccountIDs)
+    {
+        auto& slot = gAccountIdCache[index];
+
+        // The CAS to an odd value excludes other writers; if it fails, another
+        // thread wrote or is writing into this slot. That is not a problem: we
+        // just don't store our result into the cache this time.
+        if (auto s0 = slot.seq.load(std::memory_order::relaxed); (s0 & 1) == 0 &&
+            slot.seq.compare_exchange_strong(s0, s0 + 1, std::memory_order::acquire))
+        {
+            slot.id = v;
+            slot.len = static_cast<std::uint8_t>(ret.size());
+            std::copy_n(ret.data(), ret.size(), slot.encoding);
+
+            // The acquire on the CAS above keeps the writes from becoming visible
+            // before the seqlock transitions to an odd value, which means readers
+            // can detect an in-progress write. This release publishes them before
+            // the seqlock transitions to an even value.
+            slot.seq.store(s0 + 2, std::memory_order::release);
+        }
+    }
+
+    return ret;
 }
 
 template <>
 std::optional<AccountID>
 parseBase58(std::string const& s)
 {
-    auto const result = decodeBase58Token(s, TokenType::AccountID);
+    return AccountID::fromRaw(decodeBase58Token(s, TokenType::AccountID));
-    if (result.size() != AccountID::kBytes)
-        return std::nullopt;
-    return AccountID::fromRaw(result);
 }
 
 //------------------------------------------------------------------------------
@@ -148,25 +198,9 @@ parseBase58(std::string const& s)
 AccountID
 calcAccountID(PublicKey const& pk)
 {
-    static_assert(AccountID::kBytes == sizeof(RipeshaHasher::result_type));
-
     RipeshaHasher rsh;
     rsh(pk.data(), pk.size());
-    return AccountID::fromRaw(static_cast<RipeshaHasher::result_type>(rsh));
+    return AccountID{static_cast<RipeshaHasher::result_type>(rsh)};
-}
-
-AccountID const&
-xrpAccount()
-{
-    static AccountID const kAccount(beast::kZero);
-    return kAccount;
-}
-
-AccountID const&
-noAccount()
-{
-    static AccountID const kAccount(1);
-    return kAccount;
 }
 
 bool

src/libxrpl/protocol/Indexes.cpp

@@ -185,8 +185,9 @@ getBookBase(Book const& book)
 UInt256
 getQualityNext(UInt256 const& uBase)
 {
-    static constexpr UInt256 kNextQuality(
+    static constexpr UInt256 kNextQuality{
-        "0000000000000000000000000000000000000000000000010000000000000000");
+        "0000000000000000000000000000000000000000000000010000000000000000"};
+
     return uBase + kNextQuality;
 }
 
@@ -429,9 +430,9 @@ payChannel(AccountID const& src, AccountID const& dst, SeqProxy const& seq) noex
 Keylet
 nftokenPageMin(AccountID const& owner)
 {
-    std::array<std::uint8_t, 32> buf{};
+    std::array<std::uint8_t, UInt256::size()> buf{};
-    std::memcpy(buf.data(), owner.data(), owner.size());
+    std::ranges::copy(owner, buf.begin());
-    return {ltNFTOKEN_PAGE, UInt256::fromRaw(buf)};
+    return {ltNFTOKEN_PAGE, UInt256{buf}};
 }
 
 Keylet

src/libxrpl/protocol/PublicKey.cpp

@@ -295,11 +295,9 @@ verify(PublicKey const& publicKey, Slice const& m, Slice const& sig) noexcept
 NodeID
 calcNodeID(PublicKey const& pk)
 {
-    static_assert(NodeID::kBytes == sizeof(RipeshaHasher::result_type));
-
     RipeshaHasher h;
     h(pk.data(), pk.size());
-    return NodeID::fromRaw(static_cast<RipeshaHasher::result_type>(h));
+    return NodeID{static_cast<RipeshaHasher::result_type>(h)};
 }
 
 }  // namespace xrpl

src/libxrpl/protocol/STAmount.cpp

@@ -148,12 +148,12 @@ STAmount::STAmount(SerialIter& sit, SField const& name) : STBase(name)
     }
 
     Issue issue;
-    issue.currency = sit.get160();
+    issue.currency = Currency{sit.get160()};
 
     if (isXRP(issue.currency))
         Throw<std::runtime_error>("invalid native currency");
 
-    issue.account = sit.get160();
+    issue.account = AccountID{sit.get160()};
 
     if (isXRP(issue.account))
         Throw<std::runtime_error>("invalid native account");

src/libxrpl/protocol/STCurrency.cpp

@@ -19,16 +19,16 @@ STCurrency::STCurrency(SField const& name) : STBase{name}
 {
 }
 
-STCurrency::STCurrency(SerialIter& sit, SField const& name) : STBase{name}
-{
-    currency_ = sit.get160();
-}
-
 STCurrency::STCurrency(SField const& name, Currency const& currency)
     : STBase{name}, currency_{currency}
 {
 }
 
+STCurrency::STCurrency(SerialIter& sit, SField const& name)
+    : STCurrency{name, Currency{sit.get160()}}
+{
+}
+
 SerializedTypeID
 STCurrency::getSType() const
 {

src/libxrpl/protocol/STIssue.cpp

@@ -28,48 +28,38 @@ STIssue::STIssue(SField const& name) : STBase{name}
 
 STIssue::STIssue(SerialIter& sit, SField const& name) : STBase{name}
 {
+    // Either the currency of an Issue or the issuer of an MPT; the
+    // following 160 bits disambiguate.
     auto const currencyOrAccount = sit.get160();
 
-    if (isXRP(Currency::fromRaw(currencyOrAccount)))
+    if (isXRP(Currency{currencyOrAccount}))
     {
         asset_ = xrpIssue();
+        return;
     }
-    // Check if MPT
+
-    else
+    // MPT is serialized as:
+    // - 160 bits MPT issuer account
+    // - 160 bits black hole account
+    // - 32 bits sequence
+    AccountID const account{sit.get160()};
+
+    // MPT
+    if (noAccount() == account)
     {
-        // MPT is serialized as:
+        // MPT: issuer (160), noAccount() (160), sequence (32). The sequence
-        // - 160 bits MPT issuer account
+        // is stored in little-endian and get32() reads big-endian, so
-        // - 160 bits black hole account
+        // reverse it before building the canonical ID.
-        // - 32 bits sequence
+        asset_ = MPTIssue{std::byteswap(sit.get32()), AccountID{currencyOrAccount}};
-        AccountID const account = AccountID::fromRaw(sit.get160());
+        return;
-        // MPT
-        if (noAccount() == account)
-        {
-            MPTID mptID;
-            std::uint32_t sequence = sit.get32();
-            // MPTID stores the sequence in canonical big-endian bytes. STIssue
-            // ledger bytes are the legacy LE-host encoding, so convert the
-            // native get32() value to LE bytes before copying into the MPTID.
-            sequence = boost::endian::native_to_little(sequence);
-            static_assert(MPTID::size() == sizeof(sequence) + sizeof(currencyOrAccount));
-            memcpy(mptID.data(), &sequence, sizeof(sequence));
-            memcpy(
-                mptID.data() + sizeof(sequence),
-                currencyOrAccount.data(),
-                sizeof(currencyOrAccount));
-            MPTIssue const issue{mptID};
-            asset_ = issue;
-        }
-        else
-        {
-            Issue issue;
-            issue.currency = currencyOrAccount;
-            issue.account = account;
-            if (!isConsistent(issue))
-                Throw<std::runtime_error>("invalid issue: currency and account native mismatch");
-            asset_ = issue;
-        }
     }
+
+    Issue const issue{Currency{currencyOrAccount}, account};
+
+    if (!isConsistent(issue))
+        Throw<std::runtime_error>("invalid issue: currency and account native mismatch");
+
+    asset_ = issue;
 }
 
 SerializedTypeID

src/libxrpl/protocol/STPathSet.cpp

@@ -5,6 +5,7 @@
 #include <xrpl/basics/UnorderedContainers.h>
 #include <xrpl/basics/base_uint.h>
 #include <xrpl/basics/contract.h>
+#include <xrpl/basics/safe_cast.h>
 #include <xrpl/beast/hash/uhash.h>
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/json/json_value.h>
@@ -17,9 +18,13 @@
 #include <xrpl/protocol/jss.h>
 
 #include <algorithm>
+#include <concepts>
 #include <cstddef>
+#include <cstdint>
 #include <memory>
+#include <optional>
 #include <stdexcept>
+#include <type_traits>
 #include <utility>
 #include <vector>
 
@@ -36,10 +41,10 @@ STPathElement::getHash(STPathElement const& element)
     //            important. We don't even really need to fully hash the whole
     //            base_uint here, as a few bytes would do for our use.
     //
-    // The note above is only true because the result of this function reaches
+    // The note above is only true because the result of this function is only
-    // nothing but STPathElement::operator==, where it is a fast-reject
+    // used by the STPathElement equality operator as a fast-reject prefilter,
-    // prefilter ahead of the field comparisons that decide the answer.  Do not
+    // ahead of the field comparisons that then decide the answer. Do not use
-    // use it to key a container.
+    // it to key a container.
 
     for (auto const x : element.getAccountID())
         hashAccount += (hashAccount * 257) ^ x;
@@ -106,12 +111,38 @@ STPathSet::operator=(STPathSet const& other)
 
 STPathSet::STPathSet(SerialIter& sit, SField const& name) : STBase(name)
 {
-    std::vector<STPathElement> path;
+    using enum STPathElement::Type;
-    for (;;)
-    {
-        int const iType = sit.get8();
 
-        if (iType == STPathElement::TypeNone || iType == STPathElement::TypeBoundary)
+    auto parsePathElementType = [](std::underlying_type_t<STPathElement::Type> byte) noexcept
+        -> std::optional<STPathElement::Type> {
+        if (byte == std::to_underlying(TypeBoundary))
+            return TypeBoundary;
+
+        constexpr auto knownBits = static_cast<std::underlying_type_t<STPathElement::Type>>(
+            std::to_underlying(TypeAccount) | std::to_underlying(TypeCurrency) |
+            std::to_underlying(TypeIssuer) | std::to_underlying(TypeMpt));
+
+        if ((byte & ~knownBits) != 0)
+            return std::nullopt;
+
+        return static_cast<STPathElement::Type>(byte);
+    };
+
+    std::vector<STPathElement> path;
+
+    std::optional<STPathElement::Type> type;
+
+    do
+    {
+        type = parsePathElementType(sit.get8());
+
+        if (!type)
+        {
+            JLOG(debugLog().error()) << "Bad path element in pathset";
+            Throw<std::runtime_error>("bad path element");
+        }
+
+        if (type == TypeNone || type == TypeBoundary)
         {
             if (path.empty())
             {
@@ -122,28 +153,11 @@ STPathSet::STPathSet(SerialIter& sit, SField const& name) : STBase(name)
             // Move rather than converting the vector to an STPath by copy.
             value_.emplace_back(std::move(path));
             path.clear();
-
-            if (iType == STPathElement::TypeNone)
-                return;
-        }
-        else if ((iType & ~STPathElement::TypeAll) != 0)
-        {
-            JLOG(debugLog().error()) << "Bad path element " << iType << " in pathset";
-            Throw<std::runtime_error>("bad path element");
         }
         else
         {
-            auto const hasAccount = (iType & STPathElement::TypeAccount) != 0u;
+            bool const hasCurrency = ((*type & TypeCurrency) == TypeCurrency);
-            auto const hasCurrency = (iType & STPathElement::TypeCurrency) != 0u;
+            bool const hasMPT = ((*type & TypeMpt) == TypeMpt);
-            auto const hasIssuer = (iType & STPathElement::TypeIssuer) != 0u;
-            auto const hasMPT = (iType & STPathElement::TypeMpt) != 0u;
-
-            AccountID account;
-            PathAsset asset;
-            AccountID issuer;
-
-            if (hasAccount)
-                account = sit.get160();
 
             if (hasCurrency && hasMPT)
             {
@@ -151,18 +165,26 @@ STPathSet::STPathSet(SerialIter& sit, SField const& name) : STBase(name)
                 Throw<std::runtime_error>("bad path element: MPT and Currency");
             }
 
+            AccountID account;
+            AccountID issuer;
+
+            if ((*type & TypeAccount) == TypeAccount)
+                account = AccountID{sit.get160()};
+
+            PathAsset asset;
+
             if (hasCurrency)
-                asset = Currency::fromRaw(sit.get160());
+                asset = Currency{sit.get160()};
 
             if (hasMPT)
                 asset = sit.get192();
 
-            if (hasIssuer)
+            if ((*type & TypeIssuer) == TypeIssuer)
-                issuer = sit.get160();
+                issuer = AccountID{sit.get160()};
 
             path.emplace_back(account, asset, issuer, hasCurrency || hasMPT);
         }
-    }
+    } while (type != TypeNone);
 }
 
 STBase*
@@ -216,24 +238,22 @@ STPath::getJson(JsonOptions) const
     for (auto const& it : path_)
     {
         json::Value elem(json::ValueType::Object);
-        auto const iType = it.getNodeType();
 
-        elem[jss::type] = iType;
+        elem[jss::type] = safeCast<std::uint32_t>(it.getNodeType());
 
-        if ((iType & STPathElement::TypeAccount) != 0u)
+        if (it.isType(STPathElement::TypeAccount))
             elem[jss::account] = to_string(it.getAccountID());
 
         XRPL_ASSERT(
-            ((iType & STPathElement::TypeCurrency) == 0u) ||
+            !(it.hasCurrency() && it.hasMPT()),
-                ((iType & STPathElement::TypeMpt) == 0u),
             "xrpl::STPath::getJson : not type Currency and MPT");
-        if ((iType & STPathElement::TypeCurrency) != 0u)
+        if (it.hasCurrency())
             elem[jss::currency] = to_string(it.getCurrency());
 
-        if ((iType & STPathElement::TypeMpt) != 0u)
+        if (it.hasMPT())
             elem[jss::mpt_issuance_id] = to_string(it.getMPTID());
 
-        if ((iType & STPathElement::TypeIssuer) != 0u)
+        if (it.hasIssuer())
             elem[jss::issuer] = to_string(it.getIssuerID());
 
         ret.append(elem);
@@ -265,34 +285,42 @@ STPathSet::add(Serializer& s) const
     XRPL_ASSERT(getFName().fieldType == STI_PATHSET, "xrpl::STPathSet::add : valid field type");
     bool first = true;
 
+    // Workaround, since `Serializer` does not accept strongly-typed enums
+    // yet. When support is added, the static_assert will trigger, and the
+    // lambda can be removed entirely.
+    auto const toByte = [](std::same_as<STPathElement::Type> auto t) noexcept {
+        static_assert(
+            !requires(Serializer& ser) { ser.add8(t); },
+            "Serializer::add8 now accepts STPathElement::Type directly; remove toByte.");
+        return std::to_underlying(t);
+    };
+
     for (auto const& spPath : value_)
     {
         if (!first)
-            s.add8(STPathElement::TypeBoundary);
+            s.add8(toByte(STPathElement::TypeBoundary));
 
         for (auto const& speElement : spPath)
         {
-            int const iType = speElement.getNodeType();
+            s.add8(toByte(speElement.getNodeType()));
 
-            s.add8(iType);
+            if (speElement.isType(STPathElement::TypeAccount))
-
-            if ((iType & STPathElement::TypeAccount) != 0u)
                 s.addBitString(speElement.getAccountID());
 
-            if ((iType & STPathElement::TypeMpt) != 0u)
+            if (speElement.hasMPT())
                 s.addBitString(speElement.getMPTID());
 
-            if ((iType & STPathElement::TypeCurrency) != 0u)
+            if (speElement.hasCurrency())
                 s.addBitString(speElement.getCurrency());
 
-            if ((iType & STPathElement::TypeIssuer) != 0u)
+            if (speElement.hasIssuer())
                 s.addBitString(speElement.getIssuerID());
         }
 
         first = false;
     }
 
-    s.add8(STPathElement::TypeNone);
+    s.add8(toByte(STPathElement::TypeNone));
 }
 
 }  // namespace xrpl

src/libxrpl/protocol/STVector256.cpp

@@ -9,7 +9,9 @@
 #include <xrpl/protocol/Serializer.h>
 
 #include <cstddef>
+#include <cstdint>
 #include <format>
+#include <span>
 #include <stdexcept>
 #include <utility>
 
@@ -17,7 +19,7 @@ namespace xrpl {
 
 STVector256::STVector256(SerialIter& sit, SField const& name) : STBase(name)
 {
-    auto const slice = sit.getSlice(sit.getVLDataLength());
+    auto slice = sit.getSlice(sit.getVLDataLength());
 
     if (slice.size() % UInt256::size() != 0)
     {
@@ -25,12 +27,14 @@ STVector256::STVector256(SerialIter& sit, SField const& name) : STBase(name)
             std::format("Bad serialization for STVector256: {}", slice.size()));
     }
 
-    auto const cnt = slice.size() / UInt256::size();
+    value_.reserve(slice.size() / UInt256::size());
 
-    value_.reserve(cnt);
+    while (!slice.empty())
-
+    {
-    for (std::size_t i = 0; i != cnt; ++i)
+        value_.emplace_back(
-        value_.push_back(UInt256::fromRaw(slice.substr(i * UInt256::size(), UInt256::size())));
+            std::span<std::uint8_t const, UInt256::size()>{slice.data(), UInt256::size()});
+        slice += UInt256::size();
+    }
 }
 
 STBase*

src/libxrpl/protocol/Seed.cpp

@@ -104,8 +104,9 @@ parseGenericSeed(std::string const& str, bool rfc1751)
         std::string key;
         if (RFC1751::getKeyFromEnglish(key, str) == 1)
         {
-            Blob const blob(key.rbegin(), key.rend());
+            std::array<std::uint8_t, UInt128::size()> bytes{};
-            return Seed{UInt128::fromRaw(blob)};
+            std::ranges::reverse_copy(key, bytes.begin());
+            return Seed{UInt128{bytes}};
         }
     }
 

src/libxrpl/protocol/UintTypes.cpp

@@ -35,7 +35,7 @@ constexpr std::size_t kIsoCodeLength = 3;
 std::string
 to_string(Currency const& currency)
 {
-    if (currency == beast::kZero)
+    if (currency == xrpCurrency())
         return systemCurrencyCode();
 
     if (currency == noCurrency())
@@ -62,7 +62,7 @@ to_string(Currency const& currency)
 }
 
 bool
-toCurrency(Currency& currency, std::string const& code)
+toCurrency(Currency& currency, std::string_view code)
 {
     if (code.empty() || code == systemCurrencyCode())
     {
@@ -87,7 +87,7 @@ toCurrency(Currency& currency, std::string const& code)
 }
 
 Currency
-toCurrency(std::string const& code)
+toCurrency(std::string_view code)
 {
     Currency currency;
     if (!toCurrency(currency, code))
@@ -95,25 +95,4 @@ toCurrency(std::string const& code)
     return currency;
 }
 
-Currency const&
-xrpCurrency()
-{
-    static Currency const kCurrency(beast::kZero);
-    return kCurrency;
-}
-
-Currency const&
-noCurrency()
-{
-    static Currency const kCurrency(1);
-    return kCurrency;
-}
-
-Currency const&
-badCurrency()
-{
-    static Currency const kCurrency(0x5852500000000000);
-    return kCurrency;
-}
-
 }  // namespace xrpl

src/libxrpl/shamap/SHAMapNodeID.cpp

@@ -10,6 +10,7 @@
 #include <cstddef>
 #include <format>
 #include <optional>
+#include <span>
 #include <stdexcept>
 #include <string>
 
@@ -129,14 +130,15 @@ deserializeSHAMapNodeID(void const* data, std::size_t size)
 {
     std::optional<SHAMapNodeID> ret;
 
-    if (size == 33)
+    if (size == UInt256::size() + 1)
     {
-        unsigned int const depth = *(static_cast<unsigned char const*>(data) + 32);
+        std::span const bytes{static_cast<unsigned char const*>(data), size};
-        if (depth <= SHAMap::kLeafDepth)
+
+        if (unsigned int const depth = bytes[uint256::size()]; depth <= SHAMap::kLeafDepth)
         {
             // Reject a serialized ID carrying bits below its own depth. Checked before
-            // constructing, since the constructor asserts that same property.
+            // constructing the node, since the constructor asserts that same property.
-            if (auto const id = UInt256::fromVoid(data); isPrefixOfAtDepth(id, depth, id))
+            if (uint256 const id{bytes.first<uint256::size()>()}; isPrefixOfAtDepth(id, depth, id))
                 ret.emplace(depth, id);
         }
     }

src/libxrpl/tx/ApplyContext.cpp

@@ -38,7 +38,7 @@ ApplyContext::ApplyContext(
     , parentBatchId_(parentBatchId)
 {
     XRPL_ASSERT(
-        parentBatchId.has_value() == ((flags_ & TapBatch) == TapBatch),
+        parentBatchId.has_value() == ((flags_ & ApplyFlags::Batch) == ApplyFlags::Batch),
         "Parent Batch ID should be set if batch apply flag is set");
     view_.emplace(&base_, flags_);
 }
@@ -53,13 +53,14 @@ std::optional<TxMeta>
 ApplyContext::apply(TER ter)
 {
     // NOLINTNEXTLINE(bugprone-unchecked-optional-access) view_ emplaced in constructor
-    return view_->apply(base_, tx, ter, parentBatchId_, (flags_ & TapDryRun) != 0u, journal);
+    return view_->apply(
+        base_, tx, ter, parentBatchId_, (flags_ & ApplyFlags::DryRun) != ApplyFlags::None, journal);
 }
 
 void
 ApplyContext::addOrderBook(Book const& book)
 {
-    if ((flags_ & TapDryRun) == TapNone)
+    if ((flags_ & ApplyFlags::DryRun) == ApplyFlags::None)
         registry.get().getOrderBookDB().addOrderBook(book);
 }
 

src/libxrpl/tx/Transactor.cpp

@@ -134,7 +134,7 @@ preflightCheckSigningKey(STObject const& sigObject, beast::Journal j)
 std::optional<NotTEC>
 preflightCheckSimulateKeys(ApplyFlags flags, STObject const& sigObject, beast::Journal j)
 {
-    if ((flags & TapDryRun) != 0u)  // simulation
+    if ((flags & ApplyFlags::DryRun) != ApplyFlags::None)  // simulation
     {
         std::optional<Slice> const signature = sigObject[~sfTxnSignature];
         if (signature && !signature->empty())
@@ -510,7 +510,8 @@ Transactor::minimumFee(
     Fees const& fees,
     ApplyFlags flags)
 {
-    return scaleFeeLoad(baseFee, registry.getFeeTrack(), fees, (flags & TapUnlimited) != 0u);
+    return scaleFeeLoad(
+        baseFee, registry.getFeeTrack(), fees, (flags & ApplyFlags::Unlimited) != ApplyFlags::None);
 }
 
 TER
@@ -521,7 +522,7 @@ Transactor::checkFee(PreclaimContext const& ctx, XRPAmount baseFee)
 
     auto const feePaid = ctx.tx[sfFee].xrp();
 
-    if ((ctx.flags & TapBatch) != 0u)
+    if ((ctx.flags & ApplyFlags::Batch) != ApplyFlags::None)
     {
         if (feePaid == beast::kZero)
             return tesSUCCESS;
@@ -951,7 +952,8 @@ Transactor::checkSign(
         return tesSUCCESS;
     }
 
-    if (((flags & TapDryRun) != 0u) && pkSigner.empty() && !sigObject.isFieldPresent(sfSigners))
+    if (((flags & ApplyFlags::DryRun) != ApplyFlags::None) && pkSigner.empty() &&
+        !sigObject.isFieldPresent(sfSigners))
     {
         // simulate: skip signature validation when neither SigningPubKey nor
         // Signers are provided
@@ -1122,7 +1124,7 @@ Transactor::checkMultiSign(
         }
 
         XRPL_ASSERT(
-            (flags & TapDryRun) || !spk.empty(),
+            (flags & ApplyFlags::DryRun) != ApplyFlags::None || !spk.empty(),
             "xrpl::Transactor::checkMultiSign : non-empty signer or "
             "simulation");
         AccountID const signingAcctIDFromPubKey =
@@ -1604,7 +1606,7 @@ Transactor::operator()()
         if (ctx_.size() > kOversizeMetaDataCap)
             result = tecOVERSIZE;
 
-        if (isTecClaim(result) && ((view().flags() & TapFailHard) != 0u))
+        if (isTecClaim(result) && ((view().flags() & ApplyFlags::FailHard) != ApplyFlags::None))
         {
             // If the TapFailHard flag is set, a tec result
             // must not do anything
@@ -1684,7 +1686,7 @@ Transactor::operator()()
     // Once we call apply, we will no longer be able to look at view()
     metadata = ctx_.apply(result);
 
-    if ((ctx_.flags() & TapDryRun) != 0u)
+    if ((ctx_.flags() & ApplyFlags::DryRun) != ApplyFlags::None)
         return logger(result, false, std::move(metadata));
 
     return logger(result, canApply, std::move(metadata));

src/libxrpl/tx/apply.cpp

@@ -215,7 +215,7 @@ applyBatchTransactions(
     auto applyOneTransaction = [&registry, &j, &parentBatchId, &batchView](STTx const& tx) {
         OpenView perTxBatchView(kBatchView, batchView);
 
-        auto const ret = apply(registry, perTxBatchView, parentBatchId, tx, TapBatch, j);
+        auto const ret = apply(registry, perTxBatchView, parentBatchId, tx, ApplyFlags::Batch, j);
         XRPL_ASSERT(
             ret.applied == (isTesSuccess(ret.ter) || isTecClaim(ret.ter)),
             "Inner transaction should not be applied");
@@ -274,7 +274,7 @@ applyTransaction(
 {
     // Returns false if the transaction has need not be retried.
     if (retryAssured)
-        flags = flags | TapRetry;
+        flags = flags | ApplyFlags::Retry;
 
     JLOG(j.debug()) << "TXN " << txn.getTransactionID() << (retryAssured ? "/retry" : "/final");
 

src/libxrpl/tx/applySteps.cpp

@@ -346,7 +346,8 @@ preflight(
     // builds; re-check the same invariant here so a release build can't
     // silently skip a proposed transaction's signature-presence checks
     // outside of a dry run.
-    if ((flags & TapProposal) != TapNone && (flags & TapDryRun) == TapNone)
+    if ((flags & ApplyFlags::Proposal) != ApplyFlags::None &&
+        (flags & ApplyFlags::DryRun) == ApplyFlags::None)
     {
         // LCOV_EXCL_START
         JLOG(j.fatal()) << "apply (preflight): TapProposal set without TapDryRun.";
@@ -377,7 +378,8 @@ preflight(
     PreflightContext const pfCtx(registry, tx, parentBatchId, rules, flags, j);
 
     // See the comment in the other preflight() overload above.
-    if ((flags & TapProposal) != TapNone && (flags & TapDryRun) == TapNone)
+    if ((flags & ApplyFlags::Proposal) != ApplyFlags::None &&
+        (flags & ApplyFlags::DryRun) == ApplyFlags::None)
     {
         // LCOV_EXCL_START
         JLOG(j.fatal()) << "apply (preflight): TapProposal set without TapDryRun.";

src/libxrpl/tx/paths/BookStep.cpp

@@ -985,7 +985,7 @@ std::optional<std::variant<Quality, AMMOffer<TIn, TOut>>>
 BookStep<TIn, TOut, TDerived>::tip(ReadView const& view) const
 {
     // This can be simplified (and sped up) if directories are never empty.
-    Sandbox sb(&view, TapNone);
+    Sandbox sb(&view, ApplyFlags::None);
     BookTip bt(sb, book_);
     auto const lobQuality = bt.step(j_) ? std::optional<Quality>(bt.quality()) : std::nullopt;
     // Multi-path offer generates an offer with the quality

src/libxrpl/tx/paths/PaySteps.cpp

@@ -57,10 +57,8 @@ checkNear(IOUAmount const& expected, IOUAmount const& actual)
 static bool
 isXRPAccount(STPathElement const& pe)
 {
-    if (pe.getNodeType() != STPathElement::TypeAccount)
+    return pe.getNodeType() == STPathElement::TypeAccount && isXRP(pe.getAccountID());
-        return false;
+}
-    return isXRP(pe.getAccountID());
-};
 
 static std::pair<TER, std::unique_ptr<Step>>
 toStep(
@@ -71,11 +69,8 @@ toStep(
 {
     auto& j = ctx.j;
 
-    if (ctx.isFirst && e1->isAccount() &&
+    if (ctx.isFirst && e1->isAccount() && e1->hasCurrency() && e1->getPathAsset().isXRP())
-        ((e1->getNodeType() & STPathElement::TypeCurrency) != 0u) && e1->getPathAsset().isXRP())
-    {
         return makeXrpEndpointStep(ctx, e1->getAccountID());
-    }
 
     if (ctx.isLast && isXRPAccount(*e1) && e2->isAccount())
         return makeXrpEndpointStep(ctx, e2->getAccountID());
@@ -117,15 +112,9 @@ toStep(
         // LCOV_EXCL_STOP
     }
 
-    XRPL_ASSERT(
+    XRPL_ASSERT(e2->hasAsset() || e2->hasIssuer(), "xrpl::toStep : currency or issuer");
-        (e2->getNodeType() & STPathElement::TypeAsset) ||
+    PathAsset const outAsset = e2->hasAsset() ? e2->getPathAsset() : curAsset;
-            (e2->getNodeType() & STPathElement::TypeIssuer),
+    auto const outIssuer = e2->hasIssuer() ? e2->getIssuerID() : curAsset.getIssuer();
-        "xrpl::toStep : currency or issuer");
-    PathAsset const outAsset =
-        ((e2->getNodeType() & STPathElement::TypeAsset) != 0u) ? e2->getPathAsset() : curAsset;
-    auto const outIssuer = ((e2->getNodeType() & STPathElement::TypeIssuer) != 0u)
-        ? e2->getIssuerID()
-        : curAsset.getIssuer();
 
     if (isXRP(curAsset) && outAsset.isXRP())
     {
@@ -197,16 +186,15 @@ toStrand(
     for (std::size_t i = 0; i < path.size(); ++i)
     {
         auto const& pe = path[i];
-        auto const t = pe.getNodeType();
 
-        if (((t & ~STPathElement::TypeAll) != 0u) || (t == 0u))
+        if ((pe.getNodeType() & ~STPathElement::TypeAll) != STPathElement::TypeNone || pe.isNone())
             return {temBAD_PATH, Strand{}};
 
-        bool const hasAccount = (t & STPathElement::TypeAccount) != 0u;
+        bool const hasAccount = pe.isType(STPathElement::TypeAccount);
-        bool const hasIssuer = (t & STPathElement::TypeIssuer) != 0u;
+        bool const hasIssuer = pe.hasIssuer();
-        bool const hasCurrency = (t & STPathElement::TypeCurrency) != 0u;
+        bool const hasCurrency = pe.hasCurrency();
-        bool const hasMPT = (t & STPathElement::TypeMpt) != 0u;
+        bool const hasMPT = pe.hasMPT();
-        bool const hasAsset = (t & STPathElement::TypeAsset) != 0u;
+        bool const hasAsset = pe.hasAsset();
 
         if (hasAccount && (hasIssuer || hasCurrency))
             return {temBAD_PATH, Strand{}};
@@ -250,9 +238,7 @@ toStrand(
     }();
 
     // Currency or MPT
-    auto hasAsset = [](STPathElement const pe) {
+    auto hasAsset = [](STPathElement const& pe) { return pe.hasAsset(); };
-        return pe.getNodeType() & STPathElement::TypeAsset;
-    };
 
     std::vector<STPathElement> normPath;
     // reserve enough for the path, the implied source, destination,

src/libxrpl/tx/transactors/account/AccountSet.cpp

@@ -187,7 +187,8 @@ AccountSet::preclaim(PreclaimContext const& ctx)
         if (!dirIsEmpty(ctx.view, keylet::ownerDir(id)))
         {
             JLOG(ctx.j.trace()) << "Retry: Owner directory not empty.";
-            return ((ctx.flags & TapRetry) != 0u) ? TER{terOWNERS} : TER{tecOWNERS};
+            return ((ctx.flags & ApplyFlags::Retry) != ApplyFlags::None) ? TER{terOWNERS}
+                                                                         : TER{tecOWNERS};
         }
     }
 

src/libxrpl/tx/transactors/dex/AMMVote.cpp

@@ -89,7 +89,7 @@ applyVote(ApplyContext& ctx, Sandbox& sb, AccountID const& accountID, beast::Jou
     auto const lpTokensNew = ammLPHolds(sb, *ammSle, accountID, ctx.journal);
     std::optional<STAmount> minTokens;
     std::size_t minPos{0};
-    AccountID minAccount{0};
+    AccountID minAccount;
     std::uint32_t minFee{0};
     STArray updatedVoteSlots;
     Number num{0};

src/libxrpl/tx/transactors/dex/OfferCreate.cpp

@@ -295,7 +295,8 @@ OfferCreate::checkAcceptAsset(
         JLOG(j.debug()) << "delay: can't receive IOUs from non-existent issuer: "
                         << to_string(asset.getIssuer());
 
-        return ((flags & TapRetry) != 0u) ? TER{terNO_ACCOUNT} : TER{tecNO_ISSUER};
+        return ((flags & ApplyFlags::Retry) != ApplyFlags::None) ? TER{terNO_ACCOUNT}
+                                                                 : TER{tecNO_ISSUER};
     }
 
     // An account cannot create a trustline to itself, so no line can exist
@@ -318,7 +319,8 @@ OfferCreate::checkAcceptAsset(
                 {
                     JLOG(j.debug()) << "delay: can't receive IOUs from issuer with "
                                        "DisallowIncomingTrustline set";
-                    return ((flags & TapRetry) != 0u) ? TER{terNO_LINE} : TER{tecNO_LINE};
+                    return ((flags & ApplyFlags::Retry) != ApplyFlags::None) ? TER{terNO_LINE}
+                                                                             : TER{tecNO_LINE};
                 }
             }
 
@@ -326,7 +328,8 @@ OfferCreate::checkAcceptAsset(
             {
                 if (!trustLine)
                 {
-                    return ((flags & TapRetry) != 0u) ? TER{terNO_LINE} : TER{tecNO_LINE};
+                    return ((flags & ApplyFlags::Retry) != ApplyFlags::None) ? TER{terNO_LINE}
+                                                                             : TER{tecNO_LINE};
                 }
 
                 // Entries have a canonical representation, determined by a
@@ -342,7 +345,8 @@ OfferCreate::checkAcceptAsset(
                     JLOG(j.debug()) << "delay: can't receive IOUs from "
                                        "issuer without auth.";
 
-                    return ((flags & TapRetry) != 0u) ? TER{terNO_AUTH} : TER{tecNO_AUTH};
+                    return ((flags & ApplyFlags::Retry) != ApplyFlags::None) ? TER{terNO_AUTH}
+                                                                             : TER{tecNO_AUTH};
                 }
             }
 

src/libxrpl/tx/transactors/escrow/EscrowCancel.cpp

@@ -3,6 +3,7 @@
 #include <xrpl/basics/Log.h>
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/View.h>
+#include <xrpl/ledger/entries/EscrowEntry.h>
 #include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/EscrowHelpers.h>
 #include <xrpl/ledger/helpers/MPTokenHelpers.h>
@@ -94,13 +95,12 @@ EscrowCancel::preclaim(PreclaimContext const& ctx)
     if (ctx.view.rules().enabled(featureTokenEscrow))
     {
         auto const seqProxy = SeqProxy::rawSequence(ctx.tx[sfOfferSequence]);
-        auto const k = keylet::escrow(ctx.tx[sfOwner], seqProxy);
+        EscrowEntryR const escrow(ctx.tx[sfOwner], seqProxy, ctx.view);
-        auto const slep = ctx.view.read(k);
+        if (!escrow)
-        if (!slep)
             return tecNO_TARGET;
 
-        AccountID const account = (*slep)[sfAccount];
+        AccountID const account = (*escrow)[sfAccount];
-        STAmount const amount = (*slep)[sfAmount];
+        STAmount const amount = (*escrow)[sfAmount];
 
         if (!isXRP(amount))
         {
@@ -120,9 +120,8 @@ TER
 EscrowCancel::doApply()
 {
     auto const seqProxy = SeqProxy::rawSequence(ctx_.tx[sfOfferSequence]);
-    auto const k = keylet::escrow(ctx_.tx[sfOwner], seqProxy);
+    EscrowEntryW escrow(ctx_.tx[sfOwner], seqProxy, ctx_.view(), j_);
-    auto const slep = ctx_.view().peek(k);
+    if (!escrow)
-    if (!slep)
     {
         if (ctx_.view().rules().enabled(featureTokenEscrow))
             return tecINTERNAL;  // LCOV_EXCL_LINE
@@ -133,19 +132,19 @@ EscrowCancel::doApply()
     auto const now = ctx_.view().header().parentCloseTime;
 
     // No cancel time specified: can't execute at all.
-    if (!(*slep)[~sfCancelAfter])
+    if (!(*escrow)[~sfCancelAfter])
         return tecNO_PERMISSION;
 
     // Too soon: can't execute before the cancel time.
-    if (!after(now, (*slep)[sfCancelAfter]))
+    if (!after(now, (*escrow)[sfCancelAfter]))
         return tecNO_PERMISSION;
 
-    AccountID const account = (*slep)[sfAccount];
+    AccountID const account = (*escrow)[sfAccount];
 
     // Remove escrow from owner directory
     {
-        auto const page = (*slep)[sfOwnerNode];
+        auto const page = (*escrow)[sfOwnerNode];
-        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, k.key, true))
+        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, escrow.key(), true))
         {
             // LCOV_EXCL_START
             JLOG(j_.fatal()) << "Unable to delete Escrow from owner.";
@@ -155,9 +154,10 @@ EscrowCancel::doApply()
     }
 
     // Remove escrow from recipient's owner directory, if present.
-    if (auto const optPage = (*slep)[~sfDestinationNode]; optPage)
+    if (auto const optPage = (*escrow)[~sfDestinationNode]; optPage)
     {
-        if (!ctx_.view().dirRemove(keylet::ownerDir((*slep)[sfDestination]), *optPage, k.key, true))
+        if (!ctx_.view().dirRemove(
+                keylet::ownerDir((*escrow)[sfDestination]), *optPage, escrow.key(), true))
         {
             // LCOV_EXCL_START
             JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
@@ -167,13 +167,13 @@ EscrowCancel::doApply()
     }
 
     auto const sle = ctx_.view().peek(keylet::account(account));
-    STAmount const amount = slep->getFieldAmount(sfAmount);
+    STAmount const amount = escrow->getFieldAmount(sfAmount);
 
     // The return can re-create a holding the owner deleted while the escrow
     // was pending; the removed escrow must not be counted against its reserve.
     bool const recycleReserve = ctx_.view().rules().enabled(fixCleanup3_4_0);
     if (recycleReserve)
-        decreaseOwnerCountForObject(ctx_.view(), sle, slep, 1, ctx_.journal);
+        decreaseOwnerCountForObject(ctx_.view(), sle, escrow.mutableRawSle(), 1, ctx_.journal);
 
     // Transfer amount back to the owner
     if (isXRP(amount))
@@ -192,7 +192,7 @@ EscrowCancel::doApply()
                     return escrowUnlockApplyHelper<T>(
                         ctx_.getApplyViewContext(),
                         kParityRate,
-                        ctx_.view().rules().enabled(fixCleanup3_2_0) ? sle : slep,
+                        ctx_.view().rules().enabled(fixCleanup3_2_0) ? sle : escrow.mutableRawSle(),
                         preFeeBalance_,
                         amount,
                         issuer,
@@ -206,9 +206,9 @@ EscrowCancel::doApply()
             return ret;  // LCOV_EXCL_LINE
 
         // Remove escrow from issuers owner directory, if present.
-        if (auto const optPage = (*slep)[~sfIssuerNode]; optPage)
+        if (auto const optPage = (*escrow)[~sfIssuerNode]; optPage)
         {
-            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, k.key, true))
+            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, escrow.key(), true))
             {
                 // LCOV_EXCL_START
                 JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
@@ -219,10 +219,10 @@ EscrowCancel::doApply()
     }
 
     if (!recycleReserve)
-        decreaseOwnerCountForObject(ctx_.view(), sle, slep, 1, ctx_.journal);
+        decreaseOwnerCountForObject(ctx_.view(), sle, escrow.mutableRawSle(), 1, ctx_.journal);
 
     // Remove escrow from ledger
-    ctx_.view().erase(slep);
+    escrow.erase();
 
     return tesSUCCESS;
 }

src/libxrpl/tx/transactors/escrow/EscrowCreate.cpp

@@ -7,6 +7,7 @@
 #include <xrpl/core/ServiceRegistry.h>
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/View.h>
+#include <xrpl/ledger/entries/EscrowEntry.h>
 #include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/DirectoryHelpers.h>
 #include <xrpl/ledger/helpers/MPTokenHelpers.h>
@@ -481,30 +482,31 @@ EscrowCreate::doApply()
 
     // Create escrow in ledger.  Note that we use the value from the
     // sequence or ticket.  For more explanation see comments in SeqProxy.h.
-    Keylet const escrowKeylet = keylet::escrow(accountID_, ctx_.tx.getSeqProxy());
+    EscrowEntryW escrow(accountID_, ctx_.tx.getSeqProxy(), ctx_.view(), j_);
-    auto const slep = std::make_shared<SLE>(escrowKeylet);
+    Keylet const escrowKeylet = escrow.keylet();
-    (*slep)[sfAmount] = amount;
+    escrow.newSLE();
-    (*slep)[sfAccount] = accountID_;
+    (*escrow)[sfAmount] = amount;
-    (*slep)[~sfCondition] = ctx_.tx[~sfCondition];
+    (*escrow)[sfAccount] = accountID_;
-    (*slep)[~sfSourceTag] = ctx_.tx[~sfSourceTag];
+    (*escrow)[~sfCondition] = ctx_.tx[~sfCondition];
-    (*slep)[sfDestination] = ctx_.tx[sfDestination];
+    (*escrow)[~sfSourceTag] = ctx_.tx[~sfSourceTag];
-    (*slep)[~sfCancelAfter] = ctx_.tx[~sfCancelAfter];
+    (*escrow)[sfDestination] = ctx_.tx[sfDestination];
-    (*slep)[~sfFinishAfter] = ctx_.tx[~sfFinishAfter];
+    (*escrow)[~sfCancelAfter] = ctx_.tx[~sfCancelAfter];
-    (*slep)[~sfDestinationTag] = ctx_.tx[~sfDestinationTag];
+    (*escrow)[~sfFinishAfter] = ctx_.tx[~sfFinishAfter];
+    (*escrow)[~sfDestinationTag] = ctx_.tx[~sfDestinationTag];
 
     if (ctx_.view().rules().enabled(fixIncludeKeyletFields))
     {
-        (*slep)[sfSequence] = ctx_.tx.getSeqProxy().value();
+        (*escrow)[sfSequence] = ctx_.tx.getSeqProxy().value();
     }
 
     if (ctx_.view().rules().enabled(featureTokenEscrow) && !isXRP(amount))
     {
         auto const xferRate = transferRate(ctx_.view(), amount);
         if (xferRate != kParityRate)
-            (*slep)[sfTransferRate] = xferRate.value;
+            (*escrow)[sfTransferRate] = xferRate.value;
     }
 
-    ctx_.view().insert(slep);
+    escrow.insert();
 
     // Add escrow to sender's owner directory
     {
@@ -512,7 +514,7 @@ EscrowCreate::doApply()
             keylet::ownerDir(accountID_), escrowKeylet, describeOwnerDir(accountID_));
         if (!page)
             return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfOwnerNode] = *page;
+        (*escrow)[sfOwnerNode] = *page;
     }
 
     // If it's not a self-send, add escrow to recipient's owner directory.
@@ -523,7 +525,7 @@ EscrowCreate::doApply()
             ctx_.view().dirInsert(keylet::ownerDir(dest), escrowKeylet, describeOwnerDir(dest));
         if (!page)
             return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfDestinationNode] = *page;
+        (*escrow)[sfDestinationNode] = *page;
     }
 
     // IOU escrow objects are added to the issuer's owner directory to help
@@ -536,7 +538,7 @@ EscrowCreate::doApply()
             ctx_.view().dirInsert(keylet::ownerDir(issuer), escrowKeylet, describeOwnerDir(issuer));
         if (!page)
             return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfIssuerNode] = *page;
+        (*escrow)[sfIssuerNode] = *page;
     }
 
     // Deduct owner's balance
@@ -559,7 +561,7 @@ EscrowCreate::doApply()
 
     // increment owner count
     increaseOwnerCount(ctx_.getApplyViewContext(), sle, 1, ctx_.journal);
-    addSponsorToLedgerEntry(ctx_.getApplyViewContext(), slep);
+    addSponsorToLedgerEntry(ctx_.getApplyViewContext(), escrow.mutableRawSle());
     ctx_.view().update(sle);
     return tesSUCCESS;
 }

src/libxrpl/tx/transactors/escrow/EscrowFinish.cpp

@@ -9,6 +9,7 @@
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
 #include <xrpl/ledger/View.h>
+#include <xrpl/ledger/entries/EscrowEntry.h>
 #include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/CredentialHelpers.h>
 #include <xrpl/ledger/helpers/EscrowHelpers.h>
@@ -211,13 +212,12 @@ EscrowFinish::preclaim(PreclaimContext const& ctx)
     if (ctx.view.rules().enabled(featureTokenEscrow))
     {
         auto const seqProxy = SeqProxy::rawSequence(ctx.tx[sfOfferSequence]);
-        auto const k = keylet::escrow(ctx.tx[sfOwner], seqProxy);
+        EscrowEntryR const escrow(ctx.tx[sfOwner], seqProxy, ctx.view);
-        auto const slep = ctx.view.read(k);
+        if (!escrow)
-        if (!slep)
             return tecNO_TARGET;
 
-        AccountID const dest = (*slep)[sfDestination];
+        AccountID const dest = (*escrow)[sfDestination];
-        STAmount const amount = (*slep)[sfAmount];
+        STAmount const amount = (*escrow)[sfAmount];
 
         if (!isXRP(amount))
         {
@@ -237,9 +237,8 @@ TER
 EscrowFinish::doApply()
 {
     auto const seqProxy = SeqProxy::rawSequence(ctx_.tx[sfOfferSequence]);
-    auto const k = keylet::escrow(ctx_.tx[sfOwner], seqProxy);
+    EscrowEntryW escrow(ctx_.tx[sfOwner], seqProxy, ctx_.view(), j_);
-    auto const slep = ctx_.view().peek(k);
+    if (!escrow)
-    if (!slep)
     {
         if (ctx_.view().rules().enabled(featureTokenEscrow))
             return tecINTERNAL;  // LCOV_EXCL_LINE
@@ -252,11 +251,11 @@ EscrowFinish::doApply()
     auto const now = ctx_.view().header().parentCloseTime;
 
     // Too soon: can't execute before the finish time
-    if ((*slep)[~sfFinishAfter] && !after(now, (*slep)[sfFinishAfter]))
+    if ((*escrow)[~sfFinishAfter] && !after(now, (*escrow)[sfFinishAfter]))
         return tecNO_PERMISSION;
 
     // Too late: can't execute after the cancel time
-    if ((*slep)[~sfCancelAfter] && after(now, (*slep)[sfCancelAfter]))
+    if ((*escrow)[~sfCancelAfter] && after(now, (*escrow)[sfCancelAfter]))
         return tecNO_PERMISSION;
 
     // Check cryptocondition fulfillment
@@ -296,7 +295,7 @@ EscrowFinish::doApply()
             return tecCRYPTOCONDITION_ERROR;
 
         // Check against condition in the ledger entry:
-        auto const cond = (*slep)[~sfCondition];
+        auto const cond = (*escrow)[~sfCondition];
 
         // If a condition wasn't specified during creation,
         // one shouldn't be included now.
@@ -313,7 +312,7 @@ EscrowFinish::doApply()
     }
 
     // NOTE: Escrow payments cannot be used to fund accounts.
-    AccountID const destID = (*slep)[sfDestination];
+    AccountID const destID = (*escrow)[sfDestination];
     auto const sled = ctx_.view().peek(keylet::account(destID));
     if (!sled)
         return tecNO_DST;
@@ -323,12 +322,12 @@ EscrowFinish::doApply()
         !isTesSuccess(err))
         return err;
 
-    AccountID const account = (*slep)[sfAccount];
+    AccountID const account = (*escrow)[sfAccount];
 
     // Remove escrow from owner directory
     {
-        auto const page = (*slep)[sfOwnerNode];
+        auto const page = (*escrow)[sfOwnerNode];
-        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, k.key, true))
+        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, escrow.key(), true))
         {
             // LCOV_EXCL_START
             JLOG(j_.fatal()) << "Unable to delete Escrow from owner.";
@@ -338,9 +337,9 @@ EscrowFinish::doApply()
     }
 
     // Remove escrow from recipient's owner directory, if present.
-    if (auto const optPage = (*slep)[~sfDestinationNode])
+    if (auto const optPage = (*escrow)[~sfDestinationNode])
     {
-        if (!ctx_.view().dirRemove(keylet::ownerDir(destID), *optPage, k.key, true))
+        if (!ctx_.view().dirRemove(keylet::ownerDir(destID), *optPage, escrow.key(), true))
         {
             // LCOV_EXCL_START
             JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
@@ -355,9 +354,9 @@ EscrowFinish::doApply()
     bool const recycleReserve =
         ctx_.view().rules().enabled(featureSponsor) || ctx_.view().rules().enabled(fixCleanup3_4_0);
     if (recycleReserve)
-        decreaseOwnerCountForObject(ctx_.view(), account, slep, 1, ctx_.journal);
+        decreaseOwnerCountForObject(ctx_.view(), account, escrow.mutableRawSle(), 1, ctx_.journal);
 
-    STAmount const amount = slep->getFieldAmount(sfAmount);
+    STAmount const amount = escrow->getFieldAmount(sfAmount);
     // Transfer amount to destination
     if (isXRP(amount))
     {
@@ -368,8 +367,8 @@ EscrowFinish::doApply()
         if (!ctx_.view().rules().enabled(featureTokenEscrow))
             return temDISABLED;  // LCOV_EXCL_LINE
 
-        Rate lockedRate = slep->isFieldPresent(sfTransferRate)
+        Rate lockedRate = escrow->isFieldPresent(sfTransferRate)
-            ? xrpl::Rate(slep->getFieldU32(sfTransferRate))
+            ? xrpl::Rate(escrow->getFieldU32(sfTransferRate))
             : kParityRate;
         auto const issuer = amount.getIssuer();
         bool const createAsset = destID == accountID_;
@@ -392,9 +391,9 @@ EscrowFinish::doApply()
             return ret;
 
         // Remove escrow from issuers owner directory, if present.
-        if (auto const optPage = (*slep)[~sfIssuerNode]; optPage)
+        if (auto const optPage = (*escrow)[~sfIssuerNode]; optPage)
         {
-            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, k.key, true))
+            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, escrow.key(), true))
             {
                 // LCOV_EXCL_START
                 JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
@@ -407,10 +406,10 @@ EscrowFinish::doApply()
     ctx_.view().update(sled);
 
     if (!recycleReserve)
-        decreaseOwnerCountForObject(ctx_.view(), account, slep, 1, ctx_.journal);
+        decreaseOwnerCountForObject(ctx_.view(), account, escrow.mutableRawSle(), 1, ctx_.journal);
 
     // Remove escrow from ledger
-    ctx_.view().erase(slep);
+    escrow.erase();
     return tesSUCCESS;
 }
 

src/libxrpl/tx/transactors/lending/LoanSet.cpp

@@ -76,7 +76,7 @@ LoanSet::preflight(PreflightContext const& ctx)
     if (tx.isFlag(tfInnerBatchTxn) && ctx.rules.enabled(featureBatchV1_1) &&
         !tx.isFieldPresent(sfCounterparty))
     {
-        auto const parentBatchId = ctx.parentBatchId.value_or(UInt256{0});
+        auto const parentBatchId = ctx.parentBatchId.value_or(beast::kZero);
         JLOG(ctx.j.debug()) << "BatchTrace[" << parentBatchId << "]: "
                             << "no Counterparty for inner LoanSet transaction.";
         return temBAD_SIGNER;
@@ -91,7 +91,8 @@ LoanSet::preflight(PreflightContext const& ctx)
     // A proposed LoanSet is stored unsigned; its CounterpartySignature is
     // collected on-ledger afterward, so its absence here is expected, not an
     // error (On-Chain Cosigner spec §5.3.1.2).
-    if (!tx.isFlag(tfInnerBatchTxn) && !counterPartySig && (ctx.flags & TapProposal) == 0)
+    if (!tx.isFlag(tfInnerBatchTxn) && !counterPartySig &&
+        (ctx.flags & ApplyFlags::Proposal) == ApplyFlags::None)
     {
         JLOG(ctx.j.warn()) << "LoanSet transaction must have a CounterpartySignature.";
         return temBAD_SIGNER;

src/libxrpl/tx/transactors/nft/NFTokenMint.cpp

@@ -176,7 +176,7 @@ NFTokenMint::createNFTokenID(
         std::distance(buf.data(), ptr) == buf.size(),
         "xrpl::NFTokenMint::createNFTokenID : data size matches the buffer");
 
-    return UInt256::fromVoid(buf.data());
+    return uint256{buf};
 }
 
 TER

src/libxrpl/tx/transactors/proposal/TransactionProposalCreate.cpp

@@ -54,8 +54,8 @@ TransactionProposalCreate::preflight(PreflightContext const& ctx)
     try
     {
         STTx const stx{STObject{proposedTx}};
-        auto const inner =
+        auto const inner = xrpl::preflight(
-            xrpl::preflight(ctx.registry, ctx.rules, stx, TapDryRun | TapProposal, ctx.j);
+            ctx.registry, ctx.rules, stx, ApplyFlags::DryRun | ApplyFlags::Proposal, ctx.j);
         if (!isTesSuccess(inner.ter))
         {
             JLOG(ctx.j.debug()) << "TransactionProposalCreate: proposed txn "

src/libxrpl/tx/transactors/sponsor/SponsorshipTransfer.cpp

@@ -205,7 +205,7 @@ SponsorshipTransfer::preflight(PreflightContext const& ctx)
     // is collected on-ledger afterward, so its absence here is expected, not
     // an error (On-Chain Cosigner spec §5.3.1.2).
     if (isAccountReserveSponsorship && !ctx.tx.isFieldPresent(sfSponsorSignature) &&
-        (ctx.flags & TapProposal) == 0)
+        (ctx.flags & ApplyFlags::Proposal) == ApplyFlags::None)
     {
         JLOG(ctx.j.debug()) << "preflight: account sponsorship requires sfSponsorSignature";
         return temMALFORMED;

src/libxrpl/tx/transactors/system/Batch.cpp

@@ -359,7 +359,8 @@ Batch::preflight(PreflightContext const& ctx)
         // TapBatch — PreflightContext with a parentBatchId requires it.
         // LoanSet already short-circuits on tfInnerBatchTxn; it is also in
         // kDisabledTxTypes, so it never reaches this call.
-        ApplyFlags const innerFlags = TapBatch | (ctx.flags & (TapProposal | TapDryRun));
+        ApplyFlags const innerFlags =
+            ApplyFlags::Batch | (ctx.flags & (ApplyFlags::Proposal | ApplyFlags::DryRun));
         if (auto const preflightResult =
                 xrpl::preflight(ctx.registry, ctx.rules, parentBatchId, stx, innerFlags, ctx.j);
             !isTesSuccess(preflightResult.ter))
@@ -431,7 +432,7 @@ Batch::preflightSigValidated(PreflightContext const& ctx)
     // A proposed Batch is stored unsigned; its BatchSigners are collected
     // on-ledger afterward, so the signer-presence match belongs to submission
     // time, not proposal creation (On-Chain Cosigner spec §5.3.1.2).
-    if ((ctx.flags & TapProposal) != 0)
+    if ((ctx.flags & ApplyFlags::Proposal) != ApplyFlags::None)
         return tesSUCCESS;
 
     auto const parentBatchId = ctx.tx.getTransactionID();

src/libxrpl/tx/transactors/system/Change.cpp

@@ -8,6 +8,7 @@
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/core/ServiceRegistry.h>
 #include <xrpl/ledger/AmendmentTable.h>
+#include <xrpl/ledger/entries/FeeSettingsEntry.h>
 #include <xrpl/protocol/Feature.h>
 #include <xrpl/protocol/Indexes.h>
 #include <xrpl/protocol/Protocol.h>
@@ -260,16 +261,14 @@ Change::applyAmendment()
 TER
 Change::applyFee()
 {
-    auto const k = keylet::feeSettings();
+    FeeSettingsEntryW feeObject(view());
-
-    SLE::pointer feeObject = view().peek(k);
 
     if (!feeObject)
     {
-        feeObject = std::make_shared<SLE>(k);
+        feeObject.newSLE();
-        view().insert(feeObject);
+        feeObject.insert();
     }
-    auto set = [](SLE::pointer& feeObject, STTx const& tx, auto const& field) {
+    auto set = [](FeeSettingsEntryW& feeObject, STTx const& tx, auto const& field) {
         feeObject->at(field) = tx[field];
     };
     if (view().rules().enabled(featureXRPFees))
@@ -291,7 +290,7 @@ Change::applyFee()
         set(feeObject, ctx_.tx, sfReserveIncrement);
     }
 
-    view().update(feeObject);
+    feeObject.update();
 
     JLOG(j_.warn()) << "Fees have been changed";
     return tesSUCCESS;

src/test/app/AMMExtendedMPT_test.cpp

@@ -1890,7 +1890,7 @@ private:
             auto const flowResult = [&] {
                 STAmount const deliver(eth(51'000'000));
                 STAmount smax(btc(61'000'000));
-                PaymentSandbox sb(env.current().get(), TapNone);
+                PaymentSandbox sb(env.current().get(), ApplyFlags::None);
                 STPathSet paths;
                 auto ipe = [](MPTTester const& iss) {
                     return STPathElement(
@@ -1928,7 +1928,7 @@ private:
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
                 if (flowResult.removableOffers.empty())
                     return false;
-                Sandbox sb(&view, TapNone);
+                Sandbox sb(&view, ApplyFlags::None);
                 for (auto const& o : flowResult.removableOffers)
                 {
                     if (auto ok = sb.peek(keylet::offer(o)))

src/test/app/AMMExtended_test.cpp

@@ -2049,7 +2049,7 @@ private:
             auto const flowResult = [&] {
                 STAmount const deliver(USD(51));
                 STAmount smax(BTC(61));
-                PaymentSandbox sb(env.current().get(), TapNone);
+                PaymentSandbox sb(env.current().get(), ApplyFlags::None);
                 STPathSet paths;
                 auto ipe = [](Issue const& iss) {
                     return STPathElement(
@@ -2087,7 +2087,7 @@ private:
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
                 if (flowResult.removableOffers.empty())
                     return false;
-                Sandbox sb(&view, TapNone);
+                Sandbox sb(&view, ApplyFlags::None);
                 for (auto const& o : flowResult.removableOffers)
                 {
                     if (auto ok = sb.peek(keylet::offer(o)))

src/test/app/AMMMPT_test.cpp

@@ -461,8 +461,8 @@ private:
 
                 // Invalid tokens
                 {
-                    auto const mpt1 = MPTIssue{MPTID(0xabc)};
+                    auto const mpt1 = MPTIssue{MPTID{0xabc}};
-                    auto const mpt2 = MPTIssue{MPTID(0xdef)};
+                    auto const mpt2 = MPTIssue{MPTID{0xdef}};
                     ammAlice.deposit(
                         alice_,
                         1'000,
@@ -4158,7 +4158,7 @@ private:
                 auto jtx = env.jt(tx, Seq(1), Fee(10));
                 env.app().config().features.erase(featureMPTokensV2);
                 PreflightContext const ctx(
-                    env.app(), *jtx.stx, env.current()->rules(), TapNone, env.journal);
+                    env.app(), *jtx.stx, env.current()->rules(), ApplyFlags::None, env.journal);
                 auto pf = AMMBid::checkExtraFeatures(ctx);
                 BEAST_EXPECT(pf == false);
                 env.app().config().features.insert(featureMPTokensV2);
@@ -4170,7 +4170,7 @@ private:
                 jtx.jv["Asset2"].removeMember("mpt_issuance_id");
                 jtx.stx = env.ust(jtx);
                 PreflightContext const ctx(
-                    env.app(), *jtx.stx, env.current()->rules(), TapNone, env.journal);
+                    env.app(), *jtx.stx, env.current()->rules(), ApplyFlags::None, env.journal);
                 auto pf = AMMBid::preflight(ctx);
                 BEAST_EXPECT(pf == temBAD_AMM_TOKENS);
             }

src/test/app/AMM_test.cpp

@@ -603,8 +603,8 @@ private:
 
             // Invalid tokens - bogus currency
             {
-                auto const iss1 = Issue{Currency(0xabc), gw_.id()};
+                auto const iss1 = Issue{Currency{0xabc}, gw_.id()};
-                auto const iss2 = Issue{Currency(0xdef), gw_.id()};
+                auto const iss2 = Issue{Currency{0xdef}, gw_.id()};
                 ammAlice.deposit(
                     alice_,
                     1'000,
@@ -3263,7 +3263,7 @@ private:
                 auto jtx = env.jt(tx, Seq(1), Fee(baseFee));
                 env.app().config().features.erase(featureAMM);
                 PreflightContext const pfCtx(
-                    env.app(), *jtx.stx, env.current()->rules(), TapNone, env.journal);
+                    env.app(), *jtx.stx, env.current()->rules(), ApplyFlags::None, env.journal);
                 auto pf = Transactor::invokePreflight<AMMBid>(pfCtx);
                 BEAST_EXPECT(pf == temDISABLED);
                 env.app().config().features.insert(featureAMM);
@@ -3274,7 +3274,7 @@ private:
                 jtx.jv["TxnSignature"] = "deadbeef";
                 jtx.stx = env.ust(jtx);
                 PreflightContext const pfCtx(
-                    env.app(), *jtx.stx, env.current()->rules(), TapNone, env.journal);
+                    env.app(), *jtx.stx, env.current()->rules(), ApplyFlags::None, env.journal);
                 auto pf = Transactor::invokePreflight<AMMBid>(pfCtx);
                 BEAST_EXPECT(!isTesSuccess(pf));
             }
@@ -3285,7 +3285,7 @@ private:
                 jtx.jv["Asset2"].removeMember("issuer");
                 jtx.stx = env.ust(jtx);
                 PreflightContext const pfCtx(
-                    env.app(), *jtx.stx, env.current()->rules(), TapNone, env.journal);
+                    env.app(), *jtx.stx, env.current()->rules(), ApplyFlags::None, env.journal);
                 auto pf = Transactor::invokePreflight<AMMBid>(pfCtx);
                 BEAST_EXPECT(pf == temBAD_AMM_TOKENS);
             }

src/test/app/AccountSet_test.cpp

@@ -594,7 +594,7 @@ public:
         stx->at(sfSigningPubKey) = makeSlice(std::string("badkey"));
 
         env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
-            auto const result = xrpl::apply(env.app(), view, *stx, TapNone, j);
+            auto const result = xrpl::apply(env.app(), view, *stx, ApplyFlags::None, j);
             BEAST_EXPECT(result.ter == temBAD_SIGNATURE);
             BEAST_EXPECT(!result.applied);
             return result.applied;

src/test/app/Batch_test.cpp

@@ -436,7 +436,7 @@ class Batch_test : public beast::unit_test::Suite
         {
             auto jtx = env.jt(pay(alice, bob, XRP(1)), Txflags(tfInnerBatchTxn));
             PreflightContext const pfCtx(
-                env.app(), *jtx.stx, env.current()->rules(), TapNone, env.journal);
+                env.app(), *jtx.stx, env.current()->rules(), ApplyFlags::None, env.journal);
             auto const pf = Transactor::invokePreflight<Payment>(pfCtx);
             BEAST_EXPECT(pf == temINVALID_INNER_BATCH);
         }
@@ -451,7 +451,7 @@ class Batch_test : public beast::unit_test::Suite
                 disabledEnv.app(),
                 *jtx.stx,
                 disabledEnv.current()->rules(),
-                TapNone,
+                ApplyFlags::None,
                 disabledEnv.journal);
             auto const pf = Transactor::invokePreflight<Payment>(pfCtx);
             BEAST_EXPECT(pf == temINVALID_FLAG);
@@ -462,7 +462,12 @@ class Batch_test : public beast::unit_test::Suite
         {
             auto jtx = env.jt(pay(alice, bob, XRP(1)));
             PreflightContext const pfCtx(
-                env.app(), *jtx.stx, UInt256{1}, env.current()->rules(), TapBatch, env.journal);
+                env.app(),
+                *jtx.stx,
+                UInt256{1},
+                env.current()->rules(),
+                ApplyFlags::Batch,
+                env.journal);
             auto const pf = Transactor::invokePreflight<Payment>(pfCtx);
             BEAST_EXPECT(pf == temINVALID_INNER_BATCH);
         }
@@ -1590,7 +1595,7 @@ class Batch_test : public beast::unit_test::Suite
                 batch::Sig(std::vector<Reg>(kMaxBatchSigners + 1, bob)));
 
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
-                auto const result = xrpl::apply(env.app(), view, *jt.stx, TapNone, j);
+                auto const result = xrpl::apply(env.app(), view, *jt.stx, ApplyFlags::None, j);
                 BEAST_EXPECT(!result.applied && result.ter == temARRAY_TOO_LARGE);
                 return result.applied;
             });
@@ -4381,7 +4386,7 @@ class Batch_test : public beast::unit_test::Suite
 
         STTx const stx = STTx(ttAMENDMENT, [&](auto& obj) {
             obj.setAccountID(sfAccount, AccountID());
-            obj.setFieldH256(sfAmendment, UInt256(2));
+            obj.setFieldH256(sfAmendment, UInt256{2});
             obj.setFieldU32(sfLedgerSequence, env.seq(alice));
             obj.setFieldU32(sfFlags, tfInnerBatchTxn);
         });
@@ -4391,7 +4396,7 @@ class Batch_test : public beast::unit_test::Suite
         BEAST_EXPECT(!passesLocalChecks(stx, reason));
         BEAST_EXPECT(reason == "Cannot submit pseudo transactions.");
         env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
-            auto const result = xrpl::apply(env.app(), view, stx, TapNone, j);
+            auto const result = xrpl::apply(env.app(), view, stx, ApplyFlags::None, j);
             BEAST_EXPECT(!result.applied && result.ter == temINVALID_FLAG);
             return result.applied;
         });
@@ -5637,7 +5642,7 @@ class Batch_test : public beast::unit_test::Suite
                     obj.setFieldU32(sfFlags, tfInnerBatchTxn);
                 });
 
-                auto const result = xrpl::apply(env.app(), view, stx, TapNone, j);
+                auto const result = xrpl::apply(env.app(), view, stx, ApplyFlags::None, j);
                 // Must NOT be applied — signature was never checked
                 BEAST_EXPECT(!result.applied);
                 return false;

src/test/app/ConfidentialTransferExtended_test.cpp

@@ -432,16 +432,17 @@ class ConfidentialTransferExtended_test : public ConfidentialTransferTestBase
                  {.account = carol, .payAmount = 100, .convertAmount = 50}}};
             auto& mpt = confEnv.mpt;
 
-            std::vector<std::string> tooManyCredentials;
-            tooManyCredentials.reserve(9);
-            for (int i = 0; i < 9; ++i)
-                tooManyCredentials.push_back(to_string(UInt256(i)));
-
             mpt.send({
                 .account = carol,
                 .dest = bob,
                 .amt = 10,
-                .credentials = tooManyCredentials,
+                .credentials =
+                    [] {
+                        std::vector<std::string> v;
+                        for (int i = 0; i < 9; ++i)
+                            v.push_back(std::string(63, '0') + static_cast<char>('0' + i));
+                        return v;
+                    }(),
                 .err = temMALFORMED,
             });
         }
@@ -485,7 +486,7 @@ class ConfidentialTransferExtended_test : public ConfidentialTransferTestBase
                  {.account = carol, .payAmount = 100, .convertAmount = 50}}};
             auto& mpt = confEnv.mpt;
 
-            std::string const fakeCredIdx = to_string(UInt256(999));
+            std::string const fakeCredIdx = to_string(UInt256{999});
             mpt.send({
                 .account = carol,
                 .dest = bob,
@@ -861,8 +862,7 @@ class ConfidentialTransferExtended_test : public ConfidentialTransferTestBase
         // than the ticket seq (ticketSeq1).
         {
             BEAST_EXPECT(env.seq(bob) != ticketSeq1);
-            UInt256 const badCtxHash =
+            auto const badCtxHash = getConvertContextHash(bob, mptAlice.issuanceID(), env.seq(bob));
-                getConvertContextHash(bob, mptAlice.issuanceID(), env.seq(bob));
             auto const badProof = requireOptional(
                 mptAlice.getSchnorrProof(bob, badCtxHash), "Missing Schnorr Proof.");
 

src/test/app/ConfidentialTransfer_test.cpp

@@ -1745,7 +1745,8 @@ class ConfidentialTransfer_test : public ConfidentialTransferTestBase
                 (*sle)[sfConfidentialBalanceVersion] = wrappedFrom;
                 view.rawReplace(sle);
 
-                auto const result = xrpl::apply(env.app(), view, *jt.stx, TapNone, env.journal);
+                auto const result =
+                    xrpl::apply(env.app(), view, *jt.stx, ApplyFlags::None, env.journal);
                 BEAST_EXPECT(result.ter == tesSUCCESS);
                 return result.applied;
             }));

src/test/app/Credentials_test.cpp

@@ -901,8 +901,7 @@ struct Credentials_test : public beast::unit_test::Suite
 
             {
                 testcase("deleteSLE fail, bad SLE.");
-                auto view =
+                auto view = std::make_shared<ApplyViewImpl>(env.current().get(), ApplyFlags::None);
-                    std::make_shared<ApplyViewImpl>(env.current().get(), ApplyFlags::TapNone);
                 auto ter = xrpl::credentials::deleteSLE(*view, {}, env.journal);
                 BEAST_EXPECT(ter == tecNO_ENTRY);
             }
@@ -1125,7 +1124,7 @@ struct Credentials_test : public beast::unit_test::Suite
         // Create an ApplyViewImpl on top of the current closed ledger
         // and corrupt it by erasing the issuer's account SLE
         auto const open = env.current();
-        ApplyViewImpl av(&*open, TapNone);
+        ApplyViewImpl av(&*open, ApplyFlags::None);
 
         // Erase the issuer's account to simulate ledger corruption
         auto sleIssuer = av.peek(keylet::account(issuer.id()));

src/test/app/Delegate_test.cpp

@@ -25,6 +25,7 @@
 #include <test/jtx/ter.h>
 #include <test/jtx/trust.h>
 #include <test/jtx/txflags.h>
+#include <test/jtx/utility.h>
 #include <test/jtx/vault.h>
 
 #include <xrpl/basics/Number.h>

src/test/app/EscrowToken_test.cpp

@@ -2795,10 +2795,10 @@ struct EscrowToken_test : public beast::unit_test::Suite
 
             auto const seq1 = env.seq(alice);
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
-                Sandbox sb(&view, TapNone);
+                Sandbox sb(&view, ApplyFlags::None);
                 auto sleNew =
                     std::make_shared<SLE>(keylet::escrow(alice, SeqProxy::rawSequence(seq1)));
-                MPTIssue const mpt{MPTIssue{makeMptID(1, AccountID(0x4985601))}};
+                MPTIssue const mpt{MPTIssue{makeMptID(1, AccountID{0x4985601})}};
                 STAmount const amt(mpt, 10);
                 sleNew->setAccountID(sfDestination, bob);
                 sleNew->setFieldAmount(sfAmount, amt);
@@ -3023,10 +3023,10 @@ struct EscrowToken_test : public beast::unit_test::Suite
 
             auto const seq1 = env.seq(alice);
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
-                Sandbox sb(&view, TapNone);
+                Sandbox sb(&view, ApplyFlags::None);
                 auto sleNew =
                     std::make_shared<SLE>(keylet::escrow(alice, SeqProxy::rawSequence(seq1)));
-                MPTIssue const mpt{MPTIssue{makeMptID(1, AccountID(0x4985601))}};
+                MPTIssue const mpt{MPTIssue{makeMptID(1, AccountID{0x4985601})}};
                 STAmount const amt(mpt, 10);
                 sleNew->setAccountID(sfDestination, bob);
                 sleNew->setFieldAmount(sfAmount, amt);

src/test/app/Escrow_test.cpp

@@ -1302,8 +1302,8 @@ struct Escrow_test : public beast::unit_test::Suite
                 escrow::kFinishTime(env.now() + 1s),
                 Seq(1),
                 Fee(baseFee));
-            auto const pf =
+            auto const pf = preflight(
-                preflight(env.app(), env.current()->rules(), *jtx.stx, TapNone, env.journal);
+                env.app(), env.current()->rules(), *jtx.stx, ApplyFlags::None, env.journal);
             BEAST_EXPECT(isTesSuccess(pf.ter));
             BEAST_EXPECT(!pf.consequences.isBlocker());
             BEAST_EXPECT(pf.consequences.fee() == drops(baseFee));
@@ -1312,8 +1312,8 @@ struct Escrow_test : public beast::unit_test::Suite
 
         {
             auto const jtx = env.jt(escrow::cancel("bob", "alice", 3), Seq(1), Fee(baseFee));
-            auto const pf =
+            auto const pf = preflight(
-                preflight(env.app(), env.current()->rules(), *jtx.stx, TapNone, env.journal);
+                env.app(), env.current()->rules(), *jtx.stx, ApplyFlags::None, env.journal);
             BEAST_EXPECT(isTesSuccess(pf.ter));
             BEAST_EXPECT(!pf.consequences.isBlocker());
             BEAST_EXPECT(pf.consequences.fee() == drops(baseFee));
@@ -1322,8 +1322,8 @@ struct Escrow_test : public beast::unit_test::Suite
 
         {
             auto const jtx = env.jt(escrow::finish("bob", "alice", 3), Seq(1), Fee(baseFee));
-            auto const pf =
+            auto const pf = preflight(
-                preflight(env.app(), env.current()->rules(), *jtx.stx, TapNone, env.journal);
+                env.app(), env.current()->rules(), *jtx.stx, ApplyFlags::None, env.journal);
             BEAST_EXPECT(isTesSuccess(pf.ter));
             BEAST_EXPECT(!pf.consequences.isBlocker());
             BEAST_EXPECT(pf.consequences.fee() == drops(baseFee));

src/test/app/FeeVote_test.cpp

@@ -134,7 +134,7 @@ createInvalidFeeTx(
 bool
 applyFeeAndTestResult(jtx::Env& env, OpenView& view, STTx const& tx)
 {
-    auto const res = apply(env.app(), view, tx, ApplyFlags::TapNone, env.journal);
+    auto const res = apply(env.app(), view, tx, ApplyFlags::None, env.journal);
     return isTesSuccess(res.ter);
 }
 
@@ -558,8 +558,7 @@ class FeeVote_test : public beast::unit_test::Suite
         // Test invalid transaction with non-zero account - this should fail
         // validation
         auto invalidTx = STTx(ttFEE, [&](auto& obj) {
-            obj.setAccountID(sfAccount,
+            obj.setAccountID(sfAccount, AccountID{1});  // Should be zero (this makes it invalid)
-                             AccountID(1));  // Should be zero (this makes it invalid)
             obj.setFieldU32(sfLedgerSequence, ledger->seq());
             obj.setFieldAmount(sfBaseFeeDrops, XRPAmount{10});
             obj.setFieldAmount(sfReserveBaseDrops, XRPAmount{200000});

src/test/app/FlowMPT_test.cpp

@@ -333,7 +333,7 @@ struct FlowMPT_test : public beast::unit_test::Suite
                 auto const flowResult = [&] {
                     STAmount const deliver(usd(5'100));
                     STAmount smax(btc(61));
-                    PaymentSandbox sb(env.current().get(), TapNone);
+                    PaymentSandbox sb(env.current().get(), ApplyFlags::None);
                     STPathSet paths;
                     auto ipe = [](Asset const& asset) {
                         return STPathElement(
@@ -371,7 +371,7 @@ struct FlowMPT_test : public beast::unit_test::Suite
                 env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
                     if (flowResult.removableOffers.empty())
                         return false;
-                    Sandbox sb(&view, TapNone);
+                    Sandbox sb(&view, ApplyFlags::None);
                     for (auto const& o : flowResult.removableOffers)
                     {
                         if (auto ok = sb.peek(keylet::offer(o)))

src/test/app/Flow_test.cpp

@@ -476,7 +476,7 @@ struct Flow_test : public beast::unit_test::Suite
             auto const flowResult = [&] {
                 STAmount const deliver(usd(51));
                 STAmount smax(btc(61));
-                PaymentSandbox sb(env.current().get(), TapNone);
+                PaymentSandbox sb(env.current().get(), ApplyFlags::None);
                 STPathSet paths;
                 auto ipe = [](Issue const& iss) {
                     return STPathElement(
@@ -514,7 +514,7 @@ struct Flow_test : public beast::unit_test::Suite
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
                 if (flowResult.removableOffers.empty())
                     return false;
-                Sandbox sb(&view, TapNone);
+                Sandbox sb(&view, ApplyFlags::None);
                 for (auto const& o : flowResult.removableOffers)
                 {
                     if (auto ok = sb.peek(keylet::offer(o)))

src/test/app/HashRouter_test.cpp

@@ -34,13 +34,13 @@ class HashRouter_test : public beast::unit_test::Suite
         TestStopwatch stopwatch;
         HashRouter router(getSetup(2s, 1s), stopwatch);
 
-        HashRouterFlags const key1(HashRouterFlags::PRIVATE1);
+        constexpr HashRouterFlags key1(HashRouterFlags::PRIVATE1);
-        HashRouterFlags const key2(HashRouterFlags::PRIVATE2);
+        constexpr HashRouterFlags key2(HashRouterFlags::PRIVATE2);
-        HashRouterFlags const key3(HashRouterFlags::PRIVATE3);
+        constexpr HashRouterFlags key3(HashRouterFlags::PRIVATE3);
 
-        auto const ukey1 = UInt256{static_cast<std::uint64_t>(key1)};
+        UInt256 const ukey1{std::to_underlying(key1)};
-        auto const ukey2 = UInt256{static_cast<std::uint64_t>(key2)};
+        UInt256 const ukey2{std::to_underlying(key2)};
-        auto const ukey3 = UInt256{static_cast<std::uint64_t>(key3)};
+        UInt256 const ukey3{std::to_underlying(key3)};
 
         // t=0
         router.setFlags(ukey1, HashRouterFlags::PRIVATE1);
@@ -76,15 +76,15 @@ class HashRouter_test : public beast::unit_test::Suite
         TestStopwatch stopwatch;
         HashRouter router(getSetup(2s, 1s), stopwatch);
 
-        HashRouterFlags const key1(HashRouterFlags::PRIVATE1);
+        constexpr HashRouterFlags key1(HashRouterFlags::PRIVATE1);
-        HashRouterFlags const key2(HashRouterFlags::PRIVATE2);
+        constexpr HashRouterFlags key2(HashRouterFlags::PRIVATE2);
-        HashRouterFlags const key3(HashRouterFlags::PRIVATE3);
+        constexpr HashRouterFlags key3(HashRouterFlags::PRIVATE3);
-        HashRouterFlags const key4(HashRouterFlags::PRIVATE4);
+        constexpr HashRouterFlags key4(HashRouterFlags::PRIVATE4);
 
-        auto const ukey1 = UInt256{static_cast<std::uint64_t>(key1)};
+        constexpr UInt256 ukey1{std::to_underlying(key1)};
-        auto const ukey2 = UInt256{static_cast<std::uint64_t>(key2)};
+        constexpr UInt256 ukey2{std::to_underlying(key2)};
-        auto const ukey3 = UInt256{static_cast<std::uint64_t>(key3)};
+        constexpr UInt256 ukey3{std::to_underlying(key3)};
-        auto const ukey4 = UInt256{static_cast<std::uint64_t>(key4)};
+        constexpr UInt256 ukey4{std::to_underlying(key4)};
 
         BEAST_EXPECT(key1 != key2 && key2 != key3 && key3 != key4);
 
@@ -162,10 +162,11 @@ class HashRouter_test : public beast::unit_test::Suite
         TestStopwatch stopwatch;
         HashRouter router(getSetup(2s, 1s), stopwatch);
 
-        UInt256 const key1(1);
+        constexpr UInt256 key1{1};
-        UInt256 const key2(2);
+        constexpr UInt256 key2{2};
-        UInt256 const key3(3);
+        constexpr UInt256 key3{3};
-        UInt256 const key4(4);
+        constexpr UInt256 key4{4};
+
         BEAST_EXPECT(key1 != key2 && key2 != key3 && key3 != key4);
 
         HashRouterFlags flags(HashRouterFlags::BAD);  // This value is ignored
@@ -191,7 +192,8 @@ class HashRouter_test : public beast::unit_test::Suite
         TestStopwatch stopwatch;
         HashRouter router(getSetup(2s, 1s), stopwatch);
 
-        UInt256 const key1(1);
+        constexpr UInt256 key1{1};
+
         BEAST_EXPECT(router.setFlags(key1, HashRouterFlags::PRIVATE1));
         BEAST_EXPECT(!router.setFlags(key1, HashRouterFlags::PRIVATE1));
         BEAST_EXPECT(router.setFlags(key1, HashRouterFlags::PRIVATE2));
@@ -205,7 +207,7 @@ class HashRouter_test : public beast::unit_test::Suite
         TestStopwatch stopwatch;
         HashRouter router(getSetup(50s, 1s), stopwatch);
 
-        UInt256 const key1(1);
+        constexpr UInt256 key1{1};
 
         std::optional<std::set<HashRouter::PeerShortID>> peers;
 
@@ -248,7 +250,7 @@ class HashRouter_test : public beast::unit_test::Suite
         using namespace std::chrono_literals;
         TestStopwatch stopwatch;
         HashRouter router(getSetup(5s, 1s), stopwatch);
-        UInt256 const key(1);
+        constexpr UInt256 key{1};
         HashRouter::PeerShortID const peer = 1;
         HashRouterFlags flags = HashRouterFlags::UNDEFINED;
 

src/test/app/LedgerHistory_test.cpp

@@ -28,6 +28,8 @@ namespace xrpl::test {
 
 class LedgerHistory_test : public beast::unit_test::Suite
 {
+    UInt256 const dummyTxHash_ = uint256{1};
+
 public:
     /**
      * Generate a new ledger by hand, applying a specific close time offset
@@ -59,7 +61,7 @@ public:
         if (stx)
         {
             OpenView accum(&*res);
-            applyTransaction(env.app(), accum, *stx, false, TapNone, env.journal);
+            applyTransaction(env.app(), accum, *stx, false, ApplyFlags::None, env.journal);
             accum.apply(*res);
         }
         res->updateSkipList();
@@ -92,9 +94,8 @@ public:
             Env env{*this, envconfig(), std::make_unique<CheckMessageLogs>("MISMATCH ", &found)};
             LedgerHistory lh{beast::insight::NullCollector::make(), env.app()};
             auto const genesis = makeLedger({}, env, lh, 0s);
-            UInt256 const dummyTxHash{1};
+            lh.builtLedger(genesis, dummyTxHash_, {});
-            lh.builtLedger(genesis, dummyTxHash, {});
+            lh.validatedLedger(genesis, dummyTxHash_);
-            lh.validatedLedger(genesis, dummyTxHash);
 
             BEAST_EXPECT(!found);
         }
@@ -111,9 +112,8 @@ public:
             auto const ledgerA = makeLedger(genesis, env, lh, 4s);
             auto const ledgerB = makeLedger(genesis, env, lh, 40s);
 
-            UInt256 const dummyTxHash{1};
+            lh.builtLedger(ledgerA, dummyTxHash_, {});
-            lh.builtLedger(ledgerA, dummyTxHash, {});
+            lh.validatedLedger(ledgerB, dummyTxHash_);
-            lh.validatedLedger(ledgerB, dummyTxHash);
 
             BEAST_EXPECT(found);
         }
@@ -132,9 +132,8 @@ public:
             auto const ledgerAC = makeLedger(ledgerA, env, lh, 4s);
             auto const ledgerBD = makeLedger(ledgerB, env, lh, 4s);
 
-            UInt256 const dummyTxHash{1};
+            lh.builtLedger(ledgerAC, dummyTxHash_, {});
-            lh.builtLedger(ledgerAC, dummyTxHash, {});
+            lh.validatedLedger(ledgerBD, dummyTxHash_);
-            lh.validatedLedger(ledgerBD, dummyTxHash);
 
             BEAST_EXPECT(found);
         }

src/test/app/LedgerReplay_test.cpp

@@ -90,7 +90,7 @@ struct LedgerReplay_test : public beast::unit_test::Suite
         auto const lastClosedParent = ledgerMaster.getLedgerByHash(lastClosed->header().parentHash);
 
         auto const replayed = buildLedger(
-            LedgerReplay(lastClosedParent, lastClosed), TapNone, env.app(), env.journal);
+            LedgerReplay(lastClosedParent, lastClosed), ApplyFlags::None, env.app(), env.journal);
 
         BEAST_EXPECT(replayed->header().hash == lastClosed->header().hash);
     }
@@ -122,7 +122,7 @@ struct LedgerReplay_test : public beast::unit_test::Suite
         auto const lastClosedParent = ledgerMaster.getLedgerByHash(lastClosed->header().parentHash);
 
         auto const replayed = buildLedger(
-            LedgerReplay(lastClosedParent, lastClosed), TapNone, env.app(), env.journal);
+            LedgerReplay(lastClosedParent, lastClosed), ApplyFlags::None, env.app(), env.journal);
 
         BEAST_EXPECT(replayed->header().hash == lastClosed->header().hash);
     }
@@ -857,7 +857,7 @@ struct LedgerReplayer_test : public beast::unit_test::Suite
             auto request = std::make_shared<protocol::TMProofPathRequest>();
             request->set_type(protocol::TMLedgerMapType::lmACCOUNT_STATE);
             request->set_key(keylet::skip().key.data(), keylet::skip().key.size());
-            UInt256 hash(1234567);
+            constexpr UInt256 hash{1234567};
             request->set_ledgerhash(hash.data(), hash.size());
             auto reply = std::make_shared<protocol::TMProofPathResponse>(
                 server.msgHandler.processProofPathRequest(request));
@@ -874,7 +874,8 @@ struct LedgerReplayer_test : public beast::unit_test::Suite
             auto reply = std::make_shared<protocol::TMProofPathResponse>(
                 server.msgHandler.processProofPathRequest(request));
             BEAST_EXPECT(!reply->has_error());
-            BEAST_EXPECT(server.msgHandler.processProofPathResponse(reply) == ReplayMsgStatus::Ok);
+            auto resp = server.msgHandler.processProofPathResponse(reply);
+            BEAST_EXPECT(resp == ReplayMsgStatus::Ok);
 
             {
                 // bad reply: invalid hash/key sizes
@@ -966,7 +967,7 @@ struct LedgerReplayer_test : public beast::unit_test::Suite
             BEAST_EXPECT(
                 server.msgHandler.processReplayDeltaResponse(reply) == ReplayMsgStatus::BadData);
             // request, wrong hash
-            UInt256 hash(1234567);
+            constexpr UInt256 hash{1234567};
             request->set_ledgerhash(hash.data(), hash.size());
             reply = std::make_shared<protocol::TMReplayDeltaResponse>(
                 server.msgHandler.processReplayDeltaRequest(request));
@@ -1095,24 +1096,27 @@ struct LedgerReplayer_test : public beast::unit_test::Suite
     {
         testcase("TaskParameter");
 
-        auto makeSkipList = [](int count) -> std::vector<UInt256> {
+        auto const makeSkipList = [](std::size_t count) {
             std::vector<UInt256> sList;
             sList.reserve(count);
-            for (int i = 0; i < count; ++i)
+
-                sList.emplace_back(i);
+            UInt256 id{};
+            for (std::size_t i = 0; i != count; ++i, ++id)
+                sList.push_back(id);
+
             return sList;
         };
 
-        LedgerReplayTask::TaskParameter tp10(InboundLedger::Reason::GENERIC, UInt256(10), 10);
+        LedgerReplayTask::TaskParameter tp10(InboundLedger::Reason::GENERIC, UInt256{10}, 10);
-        BEAST_EXPECT(!tp10.update(UInt256(777), 5, makeSkipList(10)));
+        BEAST_EXPECT(!tp10.update(UInt256{777}, 5, makeSkipList(10)));
-        BEAST_EXPECT(!tp10.update(UInt256(10), 5, makeSkipList(8)));
+        BEAST_EXPECT(!tp10.update(UInt256{10}, 5, makeSkipList(8)));
-        BEAST_EXPECT(tp10.update(UInt256(10), 10, makeSkipList(10)));
+        BEAST_EXPECT(tp10.update(UInt256{10}, 10, makeSkipList(10)));
 
         // can merge to self
         BEAST_EXPECT(tp10.canMergeInto(tp10));
 
         // smaller task
-        LedgerReplayTask::TaskParameter tp9(InboundLedger::Reason::GENERIC, UInt256(9), 9);
+        LedgerReplayTask::TaskParameter tp9(InboundLedger::Reason::GENERIC, UInt256{9}, 9);
 
         BEAST_EXPECT(tp9.canMergeInto(tp10));
         BEAST_EXPECT(!tp10.canMergeInto(tp9));
@@ -1127,14 +1131,14 @@ struct LedgerReplayer_test : public beast::unit_test::Suite
         tp9.reason = InboundLedger::Reason::GENERIC;
         BEAST_EXPECT(tp9.canMergeInto(tp10));
 
-        tp9.finishHash = UInt256(1234);
+        tp9.finishHash = UInt256{1234};
         BEAST_EXPECT(!tp9.canMergeInto(tp10));
-        tp9.finishHash = UInt256(9);
+        tp9.finishHash = UInt256{9};
         BEAST_EXPECT(tp9.canMergeInto(tp10));
 
         // larger task
-        LedgerReplayTask::TaskParameter tp20(InboundLedger::Reason::GENERIC, UInt256(20), 20);
+        LedgerReplayTask::TaskParameter tp20(InboundLedger::Reason::GENERIC, UInt256{20}, 20);
-        BEAST_EXPECT(tp20.update(UInt256(20), 20, makeSkipList(20)));
+        BEAST_EXPECT(tp20.update(UInt256{20}, 20, makeSkipList(20)));
         BEAST_EXPECT(tp10.canMergeInto(tp20));
         BEAST_EXPECT(tp9.canMergeInto(tp20));
         BEAST_EXPECT(!tp20.canMergeInto(tp10));
@@ -1368,7 +1372,7 @@ struct LedgerReplayer_test : public beast::unit_test::Suite
         auto skipList = net.client.findSkipListAcquire(finalHash);
 
         std::uint8_t payload[55] = {0x6A, 0x09, 0xE6, 0x67, 0xF3, 0xBC, 0xC9, 0x08, 0xB2};
-        auto item = makeShamapitem(UInt256(12345), Slice(payload, sizeof(payload)));
+        auto item = makeShamapitem(UInt256{12345}, Slice(payload, sizeof(payload)));
         skipList->processData(l->seq(), item);
 
         std::vector<TaskStatus> const deltaStatuses;

src/test/app/MPToken_test.cpp

@@ -122,7 +122,7 @@ class MPToken_test : public beast::unit_test::Suite
                      .assetScale = 0,
                      .metadata = "test",
                      .flags = tfMPTRequireAuth,
-                     .domainID = UInt256(42),
+                     .domainID{42},
                      .err = temDISABLED});
             }
             else
@@ -132,7 +132,7 @@ class MPToken_test : public beast::unit_test::Suite
                     {.maxAmt = 100,
                      .assetScale = 0,
                      .metadata = "test",
-                     .domainID = UInt256(42),
+                     .domainID{42},
                      .err = temMALFORMED});
 
                 // tries to set zero DomainID
@@ -622,7 +622,7 @@ class MPToken_test : public beast::unit_test::Suite
                      .err = tecNO_PERMISSION});
 
                 // cannot set DomainID since SAV is not enabled
-                mptAlice.set({.account = alice, .domainID = UInt256(42), .err = temDISABLED});
+                mptAlice.set({.account = alice, .domainID{42}, .err = temDISABLED});
             }
             else
             {
@@ -635,16 +635,13 @@ class MPToken_test : public beast::unit_test::Suite
                 if (!features[featurePermissionedDomains] || !features[featureSingleAssetVault])
                 {
                     // cannot set DomainID since PD is not enabled
-                    mptAlice.set({.account = alice, .domainID = UInt256(42), .err = temDISABLED});
+                    mptAlice.set({.account = alice, .domainID{42}, .err = temDISABLED});
                 }
                 else if (features[featureSingleAssetVault])
                 {
                     // cannot set DomainID since Holder is set
                     mptAlice.set(
-                        {.account = alice,
+                        {.account = alice, .holder = bob, .domainID{42}, .err = temMALFORMED});
-                         .holder = bob,
-                         .domainID = UInt256(42),
-                         .err = temMALFORMED});
                 }
             }
 
@@ -725,7 +722,7 @@ class MPToken_test : public beast::unit_test::Suite
                 mptAlice.create({});
 
                 // Trying to set DomainID on a public MPTokenIssuance
-                mptAlice.set({.domainID = UInt256(42), .err = tecNO_PERMISSION});
+                mptAlice.set({.domainID = uint256{42}, .err = tecNO_PERMISSION});
 
                 mptAlice.set({.domainID = UInt256{}, .err = tecNO_PERMISSION});
             }
@@ -737,11 +734,10 @@ class MPToken_test : public beast::unit_test::Suite
                 mptAlice.create({.flags = tfMPTRequireAuth});
 
                 // Trying to set non-existing DomainID
-                mptAlice.set({.domainID = UInt256(42), .err = tecOBJECT_NOT_FOUND});
+                mptAlice.set({.domainID = uint256{42}, .err = tecOBJECT_NOT_FOUND});
 
                 // Trying to lock but locking is disabled
-                mptAlice.set(
+                mptAlice.set({.flags = tfMPTUnlock, .domainID{42}, .err = tecNO_PERMISSION});
-                    {.flags = tfMPTUnlock, .domainID = UInt256(42), .err = tecNO_PERMISSION});
 
                 mptAlice.set(
                     {.flags = tfMPTUnlock, .domainID = UInt256{}, .err = tecNO_PERMISSION});
@@ -1655,7 +1651,7 @@ class MPToken_test : public beast::unit_test::Suite
 
             env.fund(XRP(1'000), alice, bob);
 
-            STAmount const mpt{MPTID{0}, 100};
+            STAmount const mpt{MPTID{}, 100};
             auto const err =
                 !features[featureMPTokensV2] ? Ter(tecOBJECT_NOT_FOUND) : Ter(temBAD_CURRENCY);
             env(pay(alice, bob, mpt), err);
@@ -4059,7 +4055,7 @@ class MPToken_test : public beast::unit_test::Suite
                                  TER expectedTer,
                                  std::optional<std::uint64_t> expectedOutstanding,
                                  std::string const& label) {
-            ApplyViewImpl av(&*env.current(), TapNone);
+            ApplyViewImpl av(&*env.current(), ApplyFlags::None);
             auto const ter =
                 accountSendMulti(av, issuer.id(), asset, receivers, env.app().getJournal("View"));
             BEAST_EXPECTS(ter == expectedTer, label);

src/test/app/MultiSign_test.cpp

@@ -1415,17 +1415,18 @@ public:
         Account const alice{"alice", KeyType::Ed25519};
         env.fund(XRP(1000), alice);
         env.close();
-        uint8_t tag1[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x01, 0x02, 0x03,
-                          0x04, 0x05, 0x06, 0x07, 0x08, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
-                          0x07, 0x08, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
-
-        uint8_t tag2[] = "hello world some ascii 32b long";  // including 1 byte for NUL
-
-        UInt256 bogieTag = xrpl::BaseUInt<256>::fromVoid(tag1);
-        UInt256 demonTag = xrpl::BaseUInt<256>::fromVoid(tag2);
 
         // Attach phantom signers to alice and use them for a transaction.
-        env(signers(alice, 1, {{bogie_, 1, bogieTag}, {demon_, 1, demonTag}}));
+        // The tags are arbitrary strings without meaning for this test.
+        env(signers(
+            alice,
+            1,
+            {{bogie_,
+              1,
+              UInt256{"FABC2EB666E9B9D7A8E897E1AC446E13CE3189A9D81554AC5F46B0B159932CB3"}},
+             {demon_,
+              1,
+              UInt256{"7DA3B4CC19DFE4269C95F9A9B8923BBEE3F4DC4EB9D6D503DD0CA10191C2D5C0"}}}));
         env.close();
         env.require(Owners(alice, 1));
 

src/test/app/NFTokenBurn_test.cpp

@@ -776,7 +776,13 @@ class NFTokenBurn_test : public beast::unit_test::Suite
                 test::StreamSink sink{beast::Severity::Warning};
                 beast::Journal const jlog{sink};
                 ApplyContext ac{
-                    env.app(), ov, tx, tesSUCCESS, env.current()->fees().base, TapNone, jlog};
+                    env.app(),
+                    ov,
+                    tx,
+                    tesSUCCESS,
+                    env.current()->fees().base,
+                    ApplyFlags::None,
+                    jlog};
 
                 // Verify that the last page is present and contains one NFT.
                 auto lastNFTokenPage = ac.view().peek(keylet::nftokenPageMax(alice));
@@ -808,7 +814,13 @@ class NFTokenBurn_test : public beast::unit_test::Suite
                 test::StreamSink sink{beast::Severity::Warning};
                 beast::Journal const jlog{sink};
                 ApplyContext ac{
-                    env.app(), ov, tx, tesSUCCESS, env.current()->fees().base, TapNone, jlog};
+                    env.app(),
+                    ov,
+                    tx,
+                    tesSUCCESS,
+                    env.current()->fees().base,
+                    ApplyFlags::None,
+                    jlog};
 
                 // Verify that the middle  page is present.
                 auto lastNFTokenPage = ac.view().peek(keylet::nftokenPageMax(alice));

src/test/app/OfferMPT_test.cpp

@@ -6219,16 +6219,10 @@ public:
         // The type tag is a front prefix and the domain is a 32-byte suffix, so a
         // domain'd book must (a) stay distinct from its public counterpart and
         // (b) preserve the mixed-branch tag distinction that the public case has.
-        AccountID issuerX, issuerY, iouIssuer;
+        constexpr AccountID issuerX{1};
-        Currency currency;
+        constexpr AccountID iouIssuer{2};
-        BEAST_EXPECT(issuerX.parseHex("1111111111111111111111111111111111111111"));
+        constexpr Currency currency{3};
-        BEAST_EXPECT(issuerY.parseHex("2222222222222222222222222222222222222222"));
+        constexpr uint256 domainA{4};
-        BEAST_EXPECT(currency.parseHex("3333333333333333333333333333333333333333"));
-        BEAST_EXPECT(iouIssuer.parseHex("4444444444444444444444444444444444444444"));
-
-        UInt256 const domainA = UInt256::fromVoid(
-            "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD"
-            "\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD\xDD");
 
         Asset const mptX{MPTIssue{1u, issuerX}};
         Asset const iou{Issue{currency, iouIssuer}};

src/test/app/Path_test.cpp

@@ -1930,23 +1930,14 @@ public:
     {
         testcase("STPathSet::assembleAdd deduplication — O(N^2) regression");
 
-        static constexpr std::string_view kAccount1 = "A3F19C7B2E5D08146FB93A7C0E2D5184BC6F3A09";
+        constexpr AccountID kAccountID1{"A3F19C7B2E5D08146FB93A7C0E2D5184BC6F3A09"};
-        static constexpr std::string_view kAccount2 = "1D7E4B90C2A6F3851E0B9D47A2C5F8136E0A4B7D";
+        constexpr AccountID kAccountID2{"1D7E4B90C2A6F3851E0B9D47A2C5F8136E0A4B7D"};
-        static constexpr std::string_view kAccount3 = "F08C36A1D95E27B40CA1F63E8D204B7950E1C3A6";
+        constexpr AccountID kAccountID3{"F08C36A1D95E27B40CA1F63E8D204B7950E1C3A6"};
-        static constexpr std::string_view kAccount4 = "4B6209E7F1A3C85D0E94B27Af3D6018C5A7E92B4";
+        constexpr AccountID kAccountID4{"4B6209E7F1A3C85D0E94B27Af3D6018C5A7E92B4"};
-        static constexpr std::string_view kAccount5 = "9E2D7041BCA3F6589D013E7B2A4C6F80159D3E7A";
+        constexpr AccountID kAccountID5{"9E2D7041BCA3F6589D013E7B2A4C6F80159D3E7A"};
-        static constexpr std::string_view kAccount6 = "7C5A91E384F2D06BA19C4E73D820F516B3A9C0E4";
+        constexpr AccountID kAccountID6{"7C5A91E384F2D06BA19C4E73D820F516B3A9C0E4"};
-        static constexpr std::string_view kAccount7 = "2F8B043C6A1E9D75B0C38E14F6A2D509731BC4E8";
+        constexpr AccountID kAccountID7{"2F8B043C6A1E9D75B0C38E14F6A2D509731BC4E8"};
-        static constexpr std::string_view kAccount8 = "E61D9A30F47C285BA0D31E96C7B4F802513A8D6F";
+        constexpr AccountID kAccountID8{"E61D9A30F47C285BA0D31E96C7B4F802513A8D6F"};
-
-        static constexpr AccountID kAccountID1{kAccount1};
-        static constexpr AccountID kAccountID2{kAccount2};
-        static constexpr AccountID kAccountID3{kAccount3};
-        static constexpr AccountID kAccountID4{kAccount4};
-        static constexpr AccountID kAccountID5{kAccount5};
-        static constexpr AccountID kAccountID6{kAccount6};
-        static constexpr AccountID kAccountID7{kAccount7};
-        static constexpr AccountID kAccountID8{kAccount8};
 
         auto ps = STPathSet{STPathSet::DeduplicationTag{}};
 

src/test/app/PayChan_test.cpp

@@ -1404,6 +1404,30 @@ struct PayChan_test : public beast::unit_test::Suite
                 rv = env.rpc("channel_authorize", "alice", chan1StrBad, "1000");
                 BEAST_EXPECT(rv[jss::error] == "channelMalformed");
             }
+            {
+                // channel_id is not a string.
+                json::Value args{json::ValueType::Object};
+                args[jss::amount] = "2000";
+                args[jss::channel_id] = 2000;
+                args[jss::key_type] = "secp256k1";
+                args[jss::passphrase] = "passphrase_can_be_anything";
+
+                auto const ra =
+                    env.rpc("json", "channel_authorize", args.toStyledString())[jss::result];
+                BEAST_EXPECT(ra[jss::error] == "invalidParams");
+            }
+            {
+                // channel_id is not a string.
+                json::Value args{json::ValueType::Object};
+                args[jss::public_key] = chan1PkStr;
+                args[jss::channel_id] = 2000;
+                args[jss::amount] = "1000";
+                args[jss::signature] = sig;
+
+                auto const rv =
+                    env.rpc("json", "channel_verify", args.toStyledString())[jss::result];
+                BEAST_EXPECT(rv[jss::error] == "invalidParams");
+            }
             {
                 // give an ill formed base 58 public key
                 auto illFormedPk = chan1PkStr.substr(0, chan1PkStr.size() - 1);

src/test/app/PayStrandMPT_test.cpp

@@ -572,7 +572,7 @@ struct PayStrandMPT_test : public beast::unit_test::Suite
         inputs.defaultPathsAllowed = true;
         try
         {
-            PaymentSandbox sb{env.current().get(), TapNone};
+            PaymentSandbox sb{env.current().get(), ApplyFlags::None};
             {
                 auto const r = ::xrpl::path::RippleCalc::rippleCalculate(
                     sb,

src/test/app/PayStrand_test.cpp

@@ -768,7 +768,8 @@ struct PayStrand_test : public beast::unit_test::Suite
                 env,
                 usd,
                 std::nullopt,
-                STPath({STPathElement(0, xrpAccount(), xrpCurrency(), xrpAccount())}),
+                STPath({STPathElement(
+                    STPathElement::Type::TypeNone, xrpAccount(), xrpCurrency(), xrpAccount())}),
                 temBAD_PATH);
 
             // The same account can't appear more than once on a path
@@ -1076,7 +1077,7 @@ struct PayStrand_test : public beast::unit_test::Suite
         inputs.defaultPathsAllowed = true;
         try
         {
-            PaymentSandbox sb{env.current().get(), TapNone};
+            PaymentSandbox sb{env.current().get(), ApplyFlags::None};
             {
                 auto const r = ::xrpl::path::RippleCalc::rippleCalculate(
                     sb,

src/test/app/PermissionedDEX_test.cpp

@@ -58,6 +58,8 @@ using namespace jtx;
 
 class PermissionedDEX_test : public beast::unit_test::Suite
 {
+    UInt256 const badDomain_{"F10D0CC9A0F9A3CBF585B80BE09A186483668FDBDD39AA7E3370F3649CE134E5"};
+
     [[nodiscard]] static bool
     offerExists(Env const& env, Account const& account, std::uint32_t offerSeq)
     {
@@ -289,11 +291,7 @@ class PermissionedDEX_test : public beast::unit_test::Suite
             Env env(*this, features);
             auto const& [gw, domainOwner, alice, bob, carol, USD, domainID, credType] =
                 PermissionedDEX(env);
-            UInt256 const badDomain{
+            env(offer(bob, XRP(10), USD(10)), Domain(badDomain_), Ter(tecNO_PERMISSION));
-                "F10D0CC9A0F9A3CBF585B80BE09A186483668FDBDD39AA7E3370F3649CE134"
-                "E5"};
-
-            env(offer(bob, XRP(10), USD(10)), Domain(badDomain), Ter(tecNO_PERMISSION));
             env.close();
         }
 
@@ -438,14 +436,11 @@ class PermissionedDEX_test : public beast::unit_test::Suite
             Env env(*this, features);
             auto const& [gw, domainOwner, alice, bob, carol, USD, domainID, credType] =
                 PermissionedDEX(env);
-            UInt256 const badDomain{
-                "F10D0CC9A0F9A3CBF585B80BE09A186483668FDBDD39AA7E3370F3649CE134"
-                "E5"};
 
             env(pay(bob, alice, USD(10)),
                 Path(~USD),
                 Sendmax(XRP(10)),
-                Domain(badDomain),
+                Domain(badDomain_),
                 Ter(tecNO_PERMISSION));
             env.close();
         }
@@ -1700,17 +1695,13 @@ class PermissionedDEX_test : public beast::unit_test::Suite
             auto const& [gw, domainOwner, alice, bob, carol, USD, domainID, credType] =
                 PermissionedDEX(env);
 
-            UInt256 const badDomain{
-                "F10D0CC9A0F9A3CBF585B80BE09A186483668FDBDD39AA7E3370F3649CE134"
-                "E5"};
-
             env(offer(bob, XRP(10), USD(10)), Domain(domainID));
             env.close();
 
             env(pay(alice, bob, USD(10)),
                 Path(~USD),
                 Sendmax(XRP(10)),
-                Domain(badDomain),
+                Domain(badDomain_),
                 Ter(tecNO_PERMISSION));
             env.close();
         }

src/test/app/PermissionedDomains_test.cpp

@@ -102,7 +102,7 @@ class PermissionedDomains_test : public beast::unit_test::Suite
         env.fund(XRP(1000), alice);
         pdomain::Credentials const credentials{{.issuer = alice, .credType = "first credential"}};
         env(pdomain::setTx(alice, credentials), Ter(temDISABLED));
-        env(pdomain::deleteTx(alice, UInt256(75)), Ter(temDISABLED));
+        env(pdomain::deleteTx(alice, UInt256{75}), Ter(temDISABLED));
     }
 
     // Verify that bad inputs fail for each of create new and update
@@ -391,10 +391,10 @@ class PermissionedDomains_test : public beast::unit_test::Suite
         env(pdomain::setTx(alice[2], credentials1, domain2), Ter(tecNO_PERMISSION));
 
         // Update a UInt256(0) domain
-        env(pdomain::setTx(alice[0], credentials1, UInt256(0)), Ter(temMALFORMED));
+        env(pdomain::setTx(alice[0], credentials1, UInt256{0}), Ter(temMALFORMED));
 
         // Update non-existent domain
-        env(pdomain::setTx(alice[0], credentials1, UInt256(75)), Ter(tecNO_ENTRY));
+        env(pdomain::setTx(alice[0], credentials1, UInt256{75}), Ter(tecNO_ENTRY));
 
         // Wrong flag
         env(pdomain::setTx(alice[0], credentials1), Txflags(tfClawTwoAssets), Ter(temINVALID_FLAG));
@@ -452,16 +452,16 @@ class PermissionedDomains_test : public beast::unit_test::Suite
         env(pdomain::deleteTx(bob, domain), Ter(tecNO_PERMISSION));
 
         // Delete a non-existent domain.
-        env(pdomain::deleteTx(alice, UInt256(75)), Ter(tecNO_ENTRY));
+        env(pdomain::deleteTx(alice, UInt256{75}), Ter(tecNO_ENTRY));
 
         // Test bad fee
-        env(pdomain::deleteTx(alice, UInt256(75)), Ter(temBAD_FEE), Fee(1, true));
+        env(pdomain::deleteTx(alice, UInt256{75}), Ter(temBAD_FEE), Fee(1, true));
 
         // Wrong flag
         env(pdomain::deleteTx(alice, domain), Ter(temINVALID_FLAG), Txflags(tfClawTwoAssets));
 
         // Delete a zero domain.
-        env(pdomain::deleteTx(alice, UInt256(0)), Ter(temMALFORMED));
+        env(pdomain::deleteTx(alice, UInt256{0}), Ter(temMALFORMED));
 
         // Make sure owner count reflects the existing domain.
         BEAST_EXPECT(env.ownerCount(alice) == 1);

src/test/app/PseudoTx_test.cpp

@@ -47,7 +47,7 @@ struct PseudoTx_test : public beast::unit_test::Suite
 
         res.emplace_back(ttAMENDMENT, [&](auto& obj) {
             obj.setAccountID(sfAccount, AccountID());
-            obj.setFieldH256(sfAmendment, UInt256(2));
+            obj.setFieldH256(sfAmendment, UInt256{2});
             obj.setFieldU32(sfLedgerSequence, seq);
         });
 
@@ -59,11 +59,11 @@ struct PseudoTx_test : public beast::unit_test::Suite
     {
         std::vector<STTx> res;
 
-        res.emplace_back(ttACCOUNT_SET, [&](auto& obj) { obj[sfAccount] = AccountID(1); });
+        res.emplace_back(ttACCOUNT_SET, [&](auto& obj) { obj[sfAccount] = AccountID{1}; });
 
         res.emplace_back(ttPAYMENT, [&](auto& obj) {
-            obj.setAccountID(sfAccount, AccountID(2));
+            obj.setAccountID(sfAccount, AccountID{2});
-            obj.setAccountID(sfDestination, AccountID(3));
+            obj.setAccountID(sfDestination, AccountID{3});
         });
 
         return res;
@@ -82,7 +82,7 @@ struct PseudoTx_test : public beast::unit_test::Suite
             BEAST_EXPECT(!passesLocalChecks(stx, reason));
             BEAST_EXPECT(reason == "Cannot submit pseudo transactions.");
             env.app().getOpenLedger().modify([&](OpenView& view, beast::Journal j) {
-                auto const result = xrpl::apply(env.app(), view, stx, TapNone, j);
+                auto const result = xrpl::apply(env.app(), view, stx, ApplyFlags::None, j);
                 BEAST_EXPECT(!result.applied && result.ter == temINVALID);
                 return result.applied;
             });

src/test/app/RCLValidations_test.cpp

@@ -114,7 +114,7 @@ class RCLValidations_test : public beast::unit_test::Suite
         {
             RCLValidatedLedger const a{RCLValidatedLedger::MakeGenesis{}};
             BEAST_EXPECT(a.seq() == Seq{0});
-            BEAST_EXPECT(a[Seq{0}] == ID{0});
+            BEAST_EXPECT(a[Seq{0}] == ID{});
             BEAST_EXPECT(a.minSeq() == Seq{0});
         }
 
@@ -133,7 +133,7 @@ class RCLValidations_test : public beast::unit_test::Suite
                 }
                 else
                 {
-                    BEAST_EXPECT(a[s] == ID{0});
+                    BEAST_EXPECT(a[s] == ID{});
                 }
             }
         }