Merge branch 'develop' into pratik/Retire_fixUniversalNumber_amendment

include/xrpl/basics/BasicConfig.h

@@ -36,7 +36,7 @@ public:
     explicit Section(std::string name = "");
 
     /** Returns the name of this section. */
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const
     {
         return name_;
@@ -45,7 +45,7 @@ public:
     /** Returns all the lines in the section.
         This includes everything.
     */
-    std::vector<std::string> const&
+    [[nodiscard]] std::vector<std::string> const&
     lines() const
     {
         return lines_;
@@ -54,7 +54,7 @@ public:
     /** Returns all the values in the section.
         Values are non-empty lines which are not key/value pairs.
     */
-    std::vector<std::string> const&
+    [[nodiscard]] std::vector<std::string> const&
     values() const
     {
         return values_;
@@ -82,7 +82,7 @@ public:
      * @return The retrieved value. A section with an empty legacy value returns
                an empty string.
      */
-    std::string
+    [[nodiscard]] std::string
     legacy() const
     {
         if (lines_.empty())
@@ -117,11 +117,11 @@ public:
     }
 
     /** Returns `true` if a key with the given name exists. */
-    bool
+    [[nodiscard]] bool
     exists(std::string const& name) const;
 
     template <class T = std::string>
-    std::optional<T>
+    [[nodiscard]] std::optional<T>
     get(std::string const& name) const
     {
         auto const iter = lookup_.find(name);
@@ -132,7 +132,7 @@ public:
 
     /// Returns a value if present, else another value.
     template <class T>
-    T
+    [[nodiscard]] T
     value_or(std::string const& name, T const& other) const
     {
         auto const v = get<T>(name);
@@ -141,7 +141,7 @@ public:
 
     // indicates if trailing comments were seen
     // during the appending of any lines/values
-    bool
+    [[nodiscard]] bool
     had_trailing_comments() const
     {
         return had_trailing_comments_;
@@ -151,42 +151,42 @@ public:
     operator<<(std::ostream&, Section const& section);
 
     // Returns `true` if there are no key/value pairs.
-    bool
+    [[nodiscard]] bool
     empty() const
     {
         return lookup_.empty();
     }
 
     // Returns the number of key/value pairs.
-    std::size_t
+    [[nodiscard]] std::size_t
     size() const
     {
         return lookup_.size();
     }
 
     // For iteration of key/value pairs.
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const
     {
         return lookup_.cbegin();
     }
 
     // For iteration of key/value pairs.
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const
     {
         return lookup_.cbegin();
     }
 
     // For iteration of key/value pairs.
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const
     {
         return lookup_.cend();
     }
 
     // For iteration of key/value pairs.
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const
     {
         return lookup_.cend();
@@ -206,7 +206,7 @@ private:
 
 public:
     /** Returns `true` if a section with the given name exists. */
-    bool
+    [[nodiscard]] bool
     exists(std::string const& name) const;
 
     /** Returns the section with the given name.
@@ -216,7 +216,7 @@ public:
     Section&
     section(std::string const& name);
 
-    Section const&
+    [[nodiscard]] Section const&
     section(std::string const& name) const;
 
     Section const&
@@ -264,7 +264,7 @@ public:
      *         legacy value.
      *  @return Contents of the legacy value.
      */
-    std::string
+    [[nodiscard]] std::string
     legacy(std::string const& sectionName) const;
 
     friend std::ostream&
@@ -272,7 +272,7 @@ public:
 
     // indicates if trailing comments were seen
     // in any loaded Sections
-    bool
+    [[nodiscard]] bool
     had_trailing_comments() const
     {
         return std::ranges::any_of(map_, [](auto s) { return s.second.had_trailing_comments(); });

include/xrpl/basics/Buffer.h

@@ -101,13 +101,13 @@ public:
     }
 
     /** Returns the number of bytes in the buffer. */
-    std::size_t
+    [[nodiscard]] std::size_t
     size() const noexcept
     {
         return size_;
     }
 
-    bool
+    [[nodiscard]] bool
     empty() const noexcept
     {
         return 0 == size_;
@@ -125,7 +125,7 @@ public:
               to a single byte, to facilitate pointer arithmetic.
     */
     /** @{ */
-    std::uint8_t const*
+    [[nodiscard]] std::uint8_t const*
     data() const noexcept
     {
         return p_.get();
@@ -169,25 +169,25 @@ public:
         return alloc(n);
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const noexcept
     {
         return p_.get();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const noexcept
     {
         return p_.get();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const noexcept
     {
         return p_.get() + size_;
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const noexcept
     {
         return p_.get() + size_;

include/xrpl/basics/CountedObject.h

@@ -19,7 +19,7 @@ public:
     using Entry = std::pair<std::string, int>;
     using List = std::vector<Entry>;
 
-    List
+    [[nodiscard]] List
     getCounts(int minimumThreshold) const;
 
 public:
@@ -59,19 +59,19 @@ public:
             return --count_;
         }
 
-        int
+        [[nodiscard]] int
         getCount() const noexcept
         {
             return count_.load();
         }
 
-        Counter*
+        [[nodiscard]] Counter*
         getNext() const noexcept
         {
             return next_;
         }
 
-        std::string const&
+        [[nodiscard]] std::string const&
         getName() const noexcept
         {
             return name_;

include/xrpl/basics/DecayingSample.h

@@ -67,8 +67,10 @@ private:
             }
             else
             {
-                while ((elapsed--) != 0u)
+                for (; elapsed > 0; --elapsed)
+                {
                     m_value -= (m_value + Window - 1) / Window;
+                }
             }
         }
 

include/xrpl/basics/Expected.h

@@ -73,7 +73,7 @@ public:
     {
     }
 
-    constexpr E const&
+    [[nodiscard]] constexpr E const&
     value() const&
     {
         return val_;
@@ -91,7 +91,7 @@ public:
         return std::move(val_);
     }
 
-    constexpr E const&&
+    [[nodiscard]] constexpr E const&&
     value() const&&
     {
         return std::move(val_);
@@ -125,13 +125,13 @@ public:
     {
     }
 
-    constexpr bool
+    [[nodiscard]] constexpr bool
     has_value() const
     {
         return Base::has_value();
     }
 
-    constexpr T const&
+    [[nodiscard]] constexpr T const&
     value() const
     {
         return Base::value();
@@ -143,7 +143,7 @@ public:
         return Base::value();
     }
 
-    constexpr E const&
+    [[nodiscard]] constexpr E const&
     error() const
     {
         return Base::error();
@@ -210,7 +210,7 @@ public:
     {
     }
 
-    constexpr E const&
+    [[nodiscard]] constexpr E const&
     error() const
     {
         return Base::error();

include/xrpl/basics/IntrusivePointer.h

@@ -159,11 +159,11 @@ public:
     reset();
 
     /** Get the raw pointer */
-    T*
+    [[nodiscard]] T*
     get() const;
 
     /** Return the strong count */
-    std::size_t
+    [[nodiscard]] std::size_t
     use_count() const;
 
     template <class TT, class... Args>
@@ -181,7 +181,7 @@ public:
 
 private:
     /** Return the raw pointer held by this object. */
-    T*
+    [[nodiscard]] T*
     unsafeGetRawPtr() const;
 
     /** Exchange the current raw pointer held by this object with the given
@@ -260,7 +260,7 @@ public:
     lock() const;
 
     /** Return true if the strong count is zero. */
-    bool
+    [[nodiscard]] bool
     expired() const;
 
     /** Set the pointer to null and decrement the weak count.
@@ -339,7 +339,7 @@ public:
        don't lock the weak pointer. Use the `lock` method if that's what's
        needed)
      */
-    SharedIntrusive<T>
+    [[nodiscard]] SharedIntrusive<T>
     getStrong() const;
 
     /** Return true if this is a strong pointer and the strong pointer is
@@ -357,31 +357,31 @@ public:
     /** If this is a strong pointer, return the raw pointer. Otherwise
        return null.
      */
-    T*
+    [[nodiscard]] T*
     get() const;
 
     /** If this is a strong pointer, return the strong count. Otherwise
      * return 0
      */
-    std::size_t
+    [[nodiscard]] std::size_t
     use_count() const;
 
     /** Return true if there is a non-zero strong count. */
-    bool
+    [[nodiscard]] bool
     expired() const;
 
     /** If this is a strong pointer, return the strong pointer. Otherwise
         attempt to lock the weak pointer.
      */
-    SharedIntrusive<T>
+    [[nodiscard]] SharedIntrusive<T>
     lock() const;
 
     /** Return true is this represents a strong pointer. */
-    bool
+    [[nodiscard]] bool
     isStrong() const;
 
     /** Return true is this represents a weak pointer. */
-    bool
+    [[nodiscard]] bool
     isWeak() const;
 
     /** If this is a weak pointer, attempt to convert it to a strong
@@ -412,7 +412,7 @@ private:
 private:
     /** Return the raw pointer held by this object.
      */
-    T*
+    [[nodiscard]] T*
     unsafeGetRawPtr() const;
 
     enum class RefStrength { strong, weak };

include/xrpl/basics/IntrusiveRefCounts.h

@@ -207,7 +207,7 @@ private:
         RefCountPair(CountType s, CountType w) noexcept;
 
         /** Convert back to the packed integer form. */
-        FieldType
+        [[nodiscard]] FieldType
         combinedValue() const noexcept;
 
         static constexpr CountType maxStrongValue =

include/xrpl/basics/Log.h

@@ -15,6 +15,7 @@
 namespace xrpl {
 
 // DEPRECATED use beast::severities::Severity instead
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum LogSeverity {
     lsINVALID = -1,  // used to indicate an invalid severity
     lsTRACE = 0,     // Very low-level progress information, details inside
@@ -76,7 +77,7 @@ private:
             @return `true` if a system file is associated and opened for
             writing.
         */
-        bool
+        [[nodiscard]] bool
         isOpen() const noexcept;
 
         /** Associate a system file with the log.
@@ -207,6 +208,8 @@ public:
     fromString(std::string const& s);
 
 private:
+    // Need to be named before converting
+    // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
     enum {
         // Maximum line length for log messages.
         // If the message exceeds this length it will be truncated with

include/xrpl/basics/Mutex.hpp

@@ -44,7 +44,7 @@ public:
         return data_;
     }
 
-    ProtectedDataType const&
+    [[nodiscard]] ProtectedDataType const&
     get() const
     {
         return data_;
@@ -131,7 +131,7 @@ public:
      * @tparam LockType The type of lock to use
      * @return A lock on the mutex and a reference to the protected data
      */
-    template <template <typename...> typename LockType = std::lock_guard>
+    template <template <typename...> typename LockType = std::scoped_lock>
     Lock<ProtectedDataType const, LockType, MutexType>
     lock() const
     {
@@ -144,7 +144,7 @@ public:
      * @tparam LockType The type of lock to use
      * @return A lock on the mutex and a reference to the protected data
      */
-    template <template <typename...> typename LockType = std::lock_guard>
+    template <template <typename...> typename LockType = std::scoped_lock>
     Lock<ProtectedDataType, LockType, MutexType>
     lock()
     {

include/xrpl/basics/Number.h

@@ -70,7 +70,7 @@ isPowerOfTen(T value)
 struct MantissaRange
 {
     using rep = std::uint64_t;
-    enum mantissa_scale { small, large };
+    enum class mantissa_scale { small, large };
 
     explicit constexpr MantissaRange(mantissa_scale scale_)
         : min(getMin(scale_)), log(logTen(min).value_or(-1)), scale(scale_)
@@ -88,9 +88,9 @@ private:
     {
         switch (scale_)
         {
-            case small:
+            case mantissa_scale::small:
                 return 1'000'000'000'000'000ULL;
-            case large:
+            case mantissa_scale::large:
                 return 1'000'000'000'000'000'000ULL;
             default:
                 // Since this can never be called outside a non-constexpr
@@ -252,9 +252,9 @@ public:
     // Assume unsigned values are... unsigned. i.e. positive
     explicit Number(internalrep mantissa, int exponent, normalized);
 
-    constexpr rep
+    [[nodiscard]] constexpr rep
     mantissa() const noexcept;
-    constexpr int
+    [[nodiscard]] constexpr int
     exponent() const noexcept;
 
     constexpr Number
@@ -339,7 +339,7 @@ public:
     }
 
     /** Return the sign of the amount */
-    constexpr int
+    [[nodiscard]] constexpr int
     signum() const noexcept
     {
         if (negative_)
@@ -347,7 +347,7 @@ public:
         return (mantissa_ != 0u) ? 1 : 0;
     }
 
-    Number
+    [[nodiscard]] Number
     truncate() const noexcept;
 
     friend constexpr bool
@@ -384,7 +384,7 @@ public:
     root2(Number f);
 
     // Thread local rounding control.  Default is to_nearest
-    enum rounding_mode { to_nearest, towards_zero, downward, upward };
+    enum class rounding_mode { to_nearest, towards_zero, downward, upward };
     static rounding_mode
     getround();
     // Returns previously set mode
@@ -443,14 +443,14 @@ private:
     static thread_local rounding_mode mode_;
     // The available ranges for mantissa
 
-    constexpr static MantissaRange smallRange{MantissaRange::small};
+    constexpr static MantissaRange smallRange{MantissaRange::mantissa_scale::small};
     static_assert(isPowerOfTen(smallRange.min));
     static_assert(smallRange.min == 1'000'000'000'000'000LL);
     static_assert(smallRange.max == 9'999'999'999'999'999LL);
     static_assert(smallRange.log == 15);
     static_assert(smallRange.min < maxRep);
     static_assert(smallRange.max < maxRep);
-    constexpr static MantissaRange largeRange{MantissaRange::large};
+    constexpr static MantissaRange largeRange{MantissaRange::mantissa_scale::large};
     static_assert(isPowerOfTen(largeRange.min));
     static_assert(largeRange.min == 1'000'000'000'000'000'000ULL);
     static_assert(largeRange.max == internalrep(9'999'999'999'999'999'999ULL));
@@ -490,13 +490,13 @@ private:
         MantissaRange::rep const& minMantissa,
         MantissaRange::rep const& maxMantissa);
 
-    bool
+    [[nodiscard]] bool
     isnormal() const noexcept;
 
     // Copy the number, but modify the exponent by "exponentDelta". Because the
     // mantissa doesn't change, the result will be "mostly" normalized, but the
     // exponent could go out of range, so it will be checked.
-    Number
+    [[nodiscard]] Number
     shiftExponent(int exponentDelta) const;
 
     // Safely convert rep (int64) mantissa to internalrep (uint64). If the rep
@@ -759,9 +759,9 @@ to_string(MantissaRange::mantissa_scale const& scale)
 {
     switch (scale)
     {
-        case MantissaRange::small:
+        case MantissaRange::mantissa_scale::small:
             return "small";
-        case MantissaRange::large:
+        case MantissaRange::mantissa_scale::large:
             return "large";
         default:
             throw std::runtime_error("Bad scale");

include/xrpl/basics/SHAMapHash.h

@@ -20,7 +20,7 @@ public:
     {
     }
 
-    uint256 const&
+    [[nodiscard]] uint256 const&
     as_uint256() const
     {
         return hash_;
@@ -30,17 +30,17 @@ public:
     {
         return hash_;
     }
-    bool
+    [[nodiscard]] bool
     isZero() const
     {
         return hash_.isZero();
     }
-    bool
+    [[nodiscard]] bool
     isNonZero() const
     {
         return hash_.isNonZero();
     }
-    int
+    [[nodiscard]] int
     signum() const
     {
         return hash_.signum();

include/xrpl/basics/SharedWeakCachePointer.h

@@ -49,7 +49,7 @@ public:
     /** Return a strong pointer if this is already a strong pointer (i.e. don't
         lock the weak pointer. Use the `lock` method if that's what's needed)
      */
-    std::shared_ptr<T> const&
+    [[nodiscard]] std::shared_ptr<T> const&
     getStrong() const;
 
     /** Return true if this is a strong pointer and the strong pointer is
@@ -67,30 +67,30 @@ public:
     /** If this is a strong pointer, return the raw pointer. Otherwise return
         null.
      */
-    T*
+    [[nodiscard]] T*
     get() const;
 
     /** If this is a strong pointer, return the strong count. Otherwise return 0
      */
-    std::size_t
+    [[nodiscard]] std::size_t
     use_count() const;
 
     /** Return true if there is a non-zero strong count. */
-    bool
+    [[nodiscard]] bool
     expired() const;
 
     /** If this is a strong pointer, return the strong pointer. Otherwise
         attempt to lock the weak pointer.
      */
-    std::shared_ptr<T>
+    [[nodiscard]] std::shared_ptr<T>
     lock() const;
 
     /** Return true is this represents a strong pointer. */
-    bool
+    [[nodiscard]] bool
     isStrong() const;
 
     /** Return true is this represents a weak pointer. */
-    bool
+    [[nodiscard]] bool
     isWeak() const;
 
     /** If this is a weak pointer, attempt to convert it to a strong pointer.

include/xrpl/basics/SlabAllocator.h

@@ -92,7 +92,7 @@ class SlabAllocator
             std::uint8_t* ret = nullptr;  // NOLINT(misc-const-correctness)
 
             {
-                std::lock_guard const l(m_);
+                std::scoped_lock const l(m_);
 
                 ret = l_;
 
@@ -121,7 +121,7 @@ class SlabAllocator
         {
             XRPL_ASSERT(own(ptr), "xrpl::SlabAllocator::SlabBlock::deallocate : own input");
 
-            std::lock_guard const l(m_);
+            std::scoped_lock const l(m_);
 
             // Use memcpy to avoid unaligned UB
             // (will optimize to equivalent code)
@@ -180,7 +180,7 @@ public:
     ~SlabAllocator() = default;
 
     /** Returns the size of the memory block this allocator returns. */
-    constexpr std::size_t
+    [[nodiscard]] constexpr std::size_t
     size() const noexcept
     {
         return itemSize_;

include/xrpl/basics/Slice.h

@@ -74,7 +74,7 @@ public:
         @note The return type is guaranteed to be a pointer
               to a single byte, to facilitate pointer arithmetic.
     */
-    std::uint8_t const*
+    [[nodiscard]] std::uint8_t const*
     data() const noexcept
     {
         return data_;
@@ -123,25 +123,25 @@ public:
         size_ -= n;
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const noexcept
     {
         return data_;
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const noexcept
     {
         return data_;
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const noexcept
     {
         return data_ + size_;
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const noexcept
     {
         return data_ + size_;
@@ -158,7 +158,7 @@ public:
         @returns The requested subslice, if the request is valid.
         @throws std::out_of_range if pos > size()
      */
-    Slice
+    [[nodiscard]] Slice
     substr(std::size_t pos, std::size_t count = std::numeric_limits<std::size_t>::max()) const
     {
         if (pos > size())

include/xrpl/basics/TaggedCache.h

@@ -166,7 +166,7 @@ public:
 
 private:
     SharedPointerType
-    initialFetch(key_type const& key, std::lock_guard<mutex_type> const& l);
+    initialFetch(key_type const& key, std::scoped_lock<mutex_type> const& l);
 
     void
     collect_metrics();
@@ -222,19 +222,19 @@ private:
         {
         }
 
-        bool
+        [[nodiscard]] bool
         isWeak() const
         {
             if (!ptr)
                 return true;
             return ptr.isWeak();
         }
-        bool
+        [[nodiscard]] bool
         isCached() const
         {
             return ptr && ptr.isStrong();
         }
-        bool
+        [[nodiscard]] bool
         isExpired() const
         {
             return ptr.expired();
@@ -266,7 +266,7 @@ private:
         typename KeyValueCacheType::map_type& partition,
         SweptPointersVector& stuffToSweep,
         std::atomic<int>& allRemovals,
-        std::lock_guard<std::recursive_mutex> const&);
+        std::scoped_lock<std::recursive_mutex> const&);
 
     [[nodiscard]] std::thread
     sweepHelper(
@@ -275,7 +275,7 @@ private:
         typename KeyOnlyCacheType::map_type& partition,
         SweptPointersVector&,
         std::atomic<int>& allRemovals,
-        std::lock_guard<std::recursive_mutex> const&);
+        std::scoped_lock<std::recursive_mutex> const&);
 
     beast::Journal m_journal;
     clock_type& m_clock;

include/xrpl/basics/TaggedCache.ipp

@@ -69,7 +69,7 @@ inline std::size_t
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     size() const
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     return m_cache.size();
 }
 
@@ -86,7 +86,7 @@ inline int
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     getCacheSize() const
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     return m_cache_count;
 }
 
@@ -103,7 +103,7 @@ inline int
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     getTrackSize() const
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     return m_cache.size();
 }
 
@@ -120,7 +120,7 @@ inline float
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     getHitRate()
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     auto const total = static_cast<float>(m_hits + m_misses);
     return m_hits * (100.0f / std::max(1.0f, total));
 }
@@ -138,7 +138,7 @@ inline void
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     clear()
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     m_cache.clear();
     m_cache_count = 0;
 }
@@ -156,7 +156,7 @@ inline void
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     reset()
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     m_cache.clear();
     m_cache_count = 0;
     m_hits = 0;
@@ -177,7 +177,7 @@ inline bool
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     touch_if_exists(KeyComparable const& key)
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     auto const iter(m_cache.find(key));
     if (iter == m_cache.end())
     {
@@ -212,7 +212,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
 
     auto const start = std::chrono::steady_clock::now();
     {
-        std::lock_guard lock(m_mutex);
+        std::scoped_lock lock(m_mutex);
 
         if (m_target_size == 0 || (static_cast<int>(m_cache.size()) <= m_target_size))
         {
@@ -269,7 +269,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
 {
     // Remove from cache, if !valid, remove from map too. Returns true if
     // removed from cache
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
 
     auto cit = m_cache.find(key);
 
@@ -309,7 +309,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
 {
     // Return canonical value, store if needed, refresh in cache
     // Return values: true=we had the data already
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
 
     auto cit = m_cache.find(key);
 
@@ -423,7 +423,7 @@ inline SharedPointerType
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     fetch(key_type const& key)
 {
-    std::lock_guard<mutex_type> l(m_mutex);
+    std::scoped_lock<mutex_type> l(m_mutex);
     auto ret = initialFetch(key, l);
     if (!ret)
         ++m_misses;
@@ -474,7 +474,7 @@ inline auto
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     insert(key_type const& key) -> std::enable_if_t<IsKeyCache, ReturnType>
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     clock_type::time_point const now(m_clock.now());
     auto [it, inserted] = m_cache.emplace(
         std::piecewise_construct, std::forward_as_tuple(key), std::forward_as_tuple(now));
@@ -538,7 +538,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
     std::vector<key_type> v;
 
     {
-        std::lock_guard lock(m_mutex);
+        std::scoped_lock lock(m_mutex);
         v.reserve(m_cache.size());
         for (auto const& _ : m_cache)
             v.push_back(_.first);
@@ -560,7 +560,7 @@ inline double
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
     rate() const
 {
-    std::lock_guard lock(m_mutex);
+    std::scoped_lock lock(m_mutex);
     auto const tot = m_hits + m_misses;
     if (tot == 0)
         return 0;
@@ -582,7 +582,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
     fetch(key_type const& digest, Handler const& h)
 {
     {
-        std::lock_guard l(m_mutex);
+        std::scoped_lock l(m_mutex);
         if (auto ret = initialFetch(digest, l))
             return ret;
     }
@@ -591,7 +591,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
     if (!sle)
         return {};
 
-    std::lock_guard l(m_mutex);
+    std::scoped_lock l(m_mutex);
     ++m_misses;
     auto const [it, inserted] = m_cache.emplace(digest, Entry(m_clock.now(), std::move(sle)));
     if (!inserted)
@@ -611,7 +611,7 @@ template <
     class Mutex>
 inline SharedPointerType
 TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash, KeyEqual, Mutex>::
-    initialFetch(key_type const& key, std::lock_guard<mutex_type> const& l)
+    initialFetch(key_type const& key, std::scoped_lock<mutex_type> const& l)
 {
     auto cit = m_cache.find(key);
     if (cit == m_cache.end())
@@ -655,7 +655,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
     {
         beast::insight::Gauge::value_type hit_rate(0);
         {
-            std::lock_guard lock(m_mutex);
+            std::scoped_lock lock(m_mutex);
             auto const total(m_hits + m_misses);
             if (total != 0)
                 hit_rate = (m_hits * 100) / total;
@@ -681,7 +681,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
         typename KeyValueCacheType::map_type& partition,
         SweptPointersVector& stuffToSweep,
         std::atomic<int>& allRemovals,
-        std::lock_guard<std::recursive_mutex> const&)
+        std::scoped_lock<std::recursive_mutex> const&)
 {
     return std::thread([&, this]() {
         int cacheRemovals = 0;
@@ -761,7 +761,7 @@ TaggedCache<Key, T, IsKeyCache, SharedWeakUnionPointer, SharedPointerType, Hash,
         typename KeyOnlyCacheType::map_type& partition,
         SweptPointersVector&,
         std::atomic<int>& allRemovals,
-        std::lock_guard<std::recursive_mutex> const&)
+        std::scoped_lock<std::recursive_mutex> const&)
 {
     return std::thread([&, this]() {
         int cacheRemovals = 0;

include/xrpl/basics/base_uint.h

@@ -102,7 +102,7 @@ public:
     {
         return reinterpret_cast<pointer>(data_.data());
     }
-    const_pointer
+    [[nodiscard]] const_pointer
     data() const
     {
         return reinterpret_cast<const_pointer>(data_.data());
@@ -118,22 +118,22 @@ public:
     {
         return data() + bytes;
     }
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const
     {
         return data();
     }
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const
     {
         return data() + bytes;
     }
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const
     {
         return data();
     }
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const
     {
         return data() + bytes;
@@ -310,7 +310,7 @@ public:
         return fromVoid(from.data());
     }
 
-    constexpr int
+    [[nodiscard]] constexpr int
     signum() const
     {
         for (int i = 0; i < WIDTH; i++)
@@ -433,14 +433,14 @@ public:
         return ret;
     }
 
-    base_uint
+    [[nodiscard]] base_uint
     next() const
     {
         auto ret = *this;
         return ++ret;
     }
 
-    base_uint
+    [[nodiscard]] base_uint
     prev() const
     {
         auto ret = *this;
@@ -517,12 +517,12 @@ public:
     }
 
     // Deprecated.
-    bool
+    [[nodiscard]] bool
     isZero() const
     {
         return *this == beast::zero;
     }
-    bool
+    [[nodiscard]] bool
     isNonZero() const
     {
         return *this != beast::zero;

include/xrpl/basics/hardened_hash.h

@@ -32,7 +32,7 @@ make_seed_pair() noexcept
         // state_t& operator=(state_t const&) = delete;
     };
     static state_t state;
-    std::lock_guard const lock(state.mutex);
+    std::scoped_lock const lock(state.mutex);
     return {state.dist(state.gen), state.dist(state.gen)};
 }
 

include/xrpl/basics/random.h

@@ -60,7 +60,7 @@ default_prng()
     thread_local beast::xor_shift_engine engine = [] {
         std::uint64_t seed = 0;
         {
-            std::lock_guard const lk(m);
+            std::scoped_lock const lk(m);
             std::uniform_int_distribution<std::uint64_t> distribution{1};
             seed = distribution(seeder);
         }

include/xrpl/beast/asio/io_latency_probe.h

@@ -49,7 +49,7 @@ public:
         return m_ios;
     }
 
-    boost::asio::io_context const&
+    [[nodiscard]] boost::asio::io_context const&
     get_io_context() const
     {
         return m_ios;
@@ -83,7 +83,7 @@ public:
     void
     sample_one(Handler&& handler)
     {
-        std::lock_guard const lock(m_mutex);
+        std::scoped_lock const lock(m_mutex);
         if (m_cancel)
             throw std::logic_error("io_latency_probe is canceled");
         boost::asio::post(
@@ -98,7 +98,7 @@ public:
     void
     sample(Handler&& handler)
     {
-        std::lock_guard const lock(m_mutex);
+        std::scoped_lock const lock(m_mutex);
         if (m_cancel)
             throw std::logic_error("io_latency_probe is canceled");
         boost::asio::post(
@@ -122,14 +122,14 @@ private:
     void
     addref()
     {
-        std::lock_guard const lock(m_mutex);
+        std::scoped_lock const lock(m_mutex);
         ++m_count;
     }
 
     void
     release()
     {
-        std::lock_guard const lock(m_mutex);
+        std::scoped_lock const lock(m_mutex);
         if (--m_count == 0)
             m_cond.notify_all();
     }
@@ -192,7 +192,7 @@ private:
             m_handler(elapsed);
 
             {
-                std::lock_guard const lock(m_probe->m_mutex);
+                std::scoped_lock const lock(m_probe->m_mutex);
                 if (m_probe->m_cancel)
                     return;
             }

include/xrpl/beast/clock/abstract_clock.h

@@ -63,7 +63,7 @@ struct abstract_clock_wrapper : public abstract_clock<Facade>
     using typename abstract_clock<Facade>::duration;
     using typename abstract_clock<Facade>::time_point;
 
-    time_point
+    [[nodiscard]] time_point
     now() const override
     {
         return Clock::now();

include/xrpl/beast/clock/manual_clock.h

@@ -32,7 +32,7 @@ public:
     {
     }
 
-    time_point
+    [[nodiscard]] time_point
     now() const override
     {
         return now_;

include/xrpl/beast/container/detail/aged_container_iterator.h

@@ -115,7 +115,7 @@ public:
         return &m_iter->value;
     }
 
-    time_point const&
+    [[nodiscard]] time_point const&
     when() const
     {
         return m_iter->when;
@@ -136,7 +136,7 @@ private:
     {
     }
 
-    Iterator const&
+    [[nodiscard]] Iterator const&
     iterator() const
     {
         return m_iter;

include/xrpl/beast/container/detail/aged_ordered_container.h

@@ -186,7 +186,7 @@ private:
             return *this;
         }
 
-        Compare const&
+        [[nodiscard]] Compare const&
         compare() const
         {
             return *this;
@@ -295,7 +295,7 @@ private:
             return KeyValueCompare::compare();
         }
 
-        Compare const&
+        [[nodiscard]] Compare const&
         compare() const
         {
             return KeyValueCompare::compare();
@@ -307,7 +307,7 @@ private:
             return *this;
         }
 
-        KeyValueCompare const&
+        [[nodiscard]] KeyValueCompare const&
         key_compare() const
         {
             return *this;
@@ -319,7 +319,7 @@ private:
             return beast::detail::empty_base_optimization<ElementAllocator>::member();
         }
 
-        ElementAllocator const&
+        [[nodiscard]] ElementAllocator const&
         alloc() const
         {
             return beast::detail::empty_base_optimization<ElementAllocator>::member();

include/xrpl/beast/container/detail/aged_unordered_container.h

@@ -149,7 +149,7 @@ private:
             return *this;
         }
 
-        Hash const&
+        [[nodiscard]] Hash const&
         hash_function() const
         {
             return *this;
@@ -195,7 +195,7 @@ private:
             return *this;
         }
 
-        KeyEqual const&
+        [[nodiscard]] KeyEqual const&
         key_eq() const
         {
             return *this;
@@ -348,7 +348,7 @@ private:
             return *this;
         }
 
-        ValueHash const&
+        [[nodiscard]] ValueHash const&
         value_hash() const
         {
             return *this;
@@ -360,7 +360,7 @@ private:
             return ValueHash::hash_function();
         }
 
-        Hash const&
+        [[nodiscard]] Hash const&
         hash_function() const
         {
             return ValueHash::hash_function();
@@ -372,7 +372,7 @@ private:
             return *this;
         }
 
-        KeyValueEqual const&
+        [[nodiscard]] KeyValueEqual const&
         key_value_equal() const
         {
             return *this;
@@ -384,7 +384,7 @@ private:
             return key_value_equal().key_eq();
         }
 
-        KeyEqual const&
+        [[nodiscard]] KeyEqual const&
         key_eq() const
         {
             return key_value_equal().key_eq();
@@ -396,7 +396,7 @@ private:
             return beast::detail::empty_base_optimization<ElementAllocator>::member();
         }
 
-        ElementAllocator const&
+        [[nodiscard]] ElementAllocator const&
         alloc() const
         {
             return beast::detail::empty_base_optimization<ElementAllocator>::member();
@@ -433,7 +433,7 @@ private:
             m_vec.clear();
         }
 
-        size_type
+        [[nodiscard]] size_type
         max_bucket_count() const
         {
             return m_vec.max_size();
@@ -445,7 +445,7 @@ private:
             return m_max_load_factor;
         }
 
-        float const&
+        [[nodiscard]] float const&
         max_load_factor() const
         {
             return m_max_load_factor;

include/xrpl/beast/container/detail/empty_base_optimization.h

@@ -43,7 +43,7 @@ public:
         return *this;
     }
 
-    T const&
+    [[nodiscard]] T const&
     member() const noexcept
     {
         return *this;

include/xrpl/beast/core/List.h

@@ -128,7 +128,7 @@ public:
     }
 
 private:
-    reference
+    [[nodiscard]] reference
     dereference() const noexcept
     {
         return static_cast<reference>(*m_node);
@@ -287,14 +287,14 @@ public:
     /** Determine if the list is empty.
         @return `true` if the list is empty.
     */
-    bool
+    [[nodiscard]] bool
     empty() const noexcept
     {
         return size() == 0;
     }
 
     /** Returns the number of elements in the list. */
-    size_type
+    [[nodiscard]] size_type
     size() const noexcept
     {
         return m_size;
@@ -314,7 +314,7 @@ public:
         @invariant The list may not be empty.
         @return A const reference to the first element.
     */
-    const_reference
+    [[nodiscard]] const_reference
     front() const noexcept
     {
         return element_from(m_head.m_next);
@@ -334,7 +334,7 @@ public:
         @invariant The list may not be empty.
         @return A const reference to the last element.
     */
-    const_reference
+    [[nodiscard]] const_reference
     back() const noexcept
     {
         return element_from(m_tail.m_prev);
@@ -352,7 +352,7 @@ public:
     /** Obtain a const iterator to the beginning of the list.
         @return A const iterator pointing to the beginning of the list.
     */
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const noexcept
     {
         return const_iterator(m_head.m_next);
@@ -361,7 +361,7 @@ public:
     /** Obtain a const iterator to the beginning of the list.
         @return A const iterator pointing to the beginning of the list.
     */
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const noexcept
     {
         return const_iterator(m_head.m_next);
@@ -379,7 +379,7 @@ public:
     /** Obtain a const iterator to the end of the list.
         @return A constiterator pointing to the end of the list.
     */
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const noexcept
     {
         return const_iterator(&m_tail);
@@ -388,7 +388,7 @@ public:
     /** Obtain a const iterator to the end of the list
         @return A constiterator pointing to the end of the list.
     */
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const noexcept
     {
         return const_iterator(&m_tail);
@@ -549,7 +549,7 @@ public:
         @param element The element to obtain an iterator for.
         @return A const iterator to the element.
     */
-    const_iterator
+    [[nodiscard]] const_iterator
     const_iterator_to(T const& element) const noexcept
     {
         return const_iterator(static_cast<Node const*>(&element));

include/xrpl/beast/core/LockFreeStack.h

@@ -162,7 +162,7 @@ public:
     operator=(LockFreeStack const&) = delete;
 
     /** Returns true if the stack is empty. */
-    bool
+    [[nodiscard]] bool
     empty() const
     {
         return m_head.load() == &m_end;
@@ -237,25 +237,25 @@ public:
         return iterator(&m_end);
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const
     {
         return const_iterator(m_head.load());
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const
     {
         return const_iterator(&m_end);
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const
     {
         return const_iterator(m_head.load());
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const
     {
         return const_iterator(&m_end);

include/xrpl/beast/core/SemanticVersion.h

@@ -37,15 +37,15 @@ public:
     parse(std::string_view input);
 
     /** Produce a string from semantic version components. */
-    std::string
+    [[nodiscard]] std::string
     print() const;
 
-    bool
+    [[nodiscard]] bool
     isRelease() const noexcept
     {
         return preReleaseIdentifiers.empty();
     }
-    bool
+    [[nodiscard]] bool
     isPreRelease() const noexcept
     {
         return !isRelease();

include/xrpl/beast/insight/Event.h

@@ -45,7 +45,7 @@ public:
             m_impl->notify(ceil<value_type>(value));
     }
 
-    std::shared_ptr<EventImpl> const&
+    [[nodiscard]] std::shared_ptr<EventImpl> const&
     impl() const
     {
         return m_impl;

include/xrpl/beast/insight/Gauge.h

@@ -108,7 +108,7 @@ public:
     }
     /** @} */
 
-    std::shared_ptr<GaugeImpl> const&
+    [[nodiscard]] std::shared_ptr<GaugeImpl> const&
     impl() const
     {
         return m_impl;

include/xrpl/beast/insight/Group.h

@@ -14,7 +14,7 @@ public:
     using ptr = std::shared_ptr<Group>;
 
     /** Returns the name of this group, for diagnostics. */
-    virtual std::string const&
+    [[nodiscard]] virtual std::string const&
     name() const = 0;
 };
 

include/xrpl/beast/insight/Hook.h

@@ -24,7 +24,7 @@ public:
     {
     }
 
-    std::shared_ptr<HookImpl> const&
+    [[nodiscard]] std::shared_ptr<HookImpl> const&
     impl() const
     {
         return m_impl;

include/xrpl/beast/insight/Meter.h

@@ -63,7 +63,7 @@ public:
     }
     /** @} */
 
-    std::shared_ptr<MeterImpl> const&
+    [[nodiscard]] std::shared_ptr<MeterImpl> const&
     impl() const
     {
         return m_impl;

include/xrpl/beast/net/IPEndpoint.h

@@ -32,25 +32,25 @@ public:
     from_string(std::string const& s);
 
     /** Returns a string representing the endpoint. */
-    std::string
+    [[nodiscard]] std::string
     to_string() const;
 
     /** Returns the port number on the endpoint. */
-    Port
+    [[nodiscard]] Port
     port() const
     {
         return m_port;
     }
 
     /** Returns a new Endpoint with a different port. */
-    Endpoint
+    [[nodiscard]] Endpoint
     at_port(Port port) const
     {
         return Endpoint(m_addr, port);
     }
 
     /** Returns the address portion of this endpoint. */
-    Address const&
+    [[nodiscard]] Address const&
     address() const
     {
         return m_addr;
@@ -58,22 +58,22 @@ public:
 
     /** Convenience accessors for the address part. */
     /** @{ */
-    bool
+    [[nodiscard]] bool
     is_v4() const
     {
         return m_addr.is_v4();
     }
-    bool
+    [[nodiscard]] bool
     is_v6() const
     {
         return m_addr.is_v6();
     }
-    AddressV4
+    [[nodiscard]] AddressV4
     to_v4() const
     {
         return m_addr.to_v4();
     }
-    AddressV6
+    [[nodiscard]] AddressV6
     to_v6() const
     {
         return m_addr.to_v6();

include/xrpl/beast/test/yield_to.h

@@ -43,8 +43,10 @@ public:
         : work_(boost::asio::make_work_guard(ios_))
     {
         threads_.reserve(concurrency);
-        while ((concurrency--) != 0u)
+        for (std::size_t i = 0; i < concurrency; ++i)
+        {
             threads_.emplace_back([&] { ios_.run(); });
+        }
     }
 
     ~enable_yield_to()
@@ -113,7 +115,7 @@ enable_yield_to::spawn(F0&& f, FN&&... fn)
         boost::context::fixedsize_stack(2 * 1024 * 1024),
         [&](yield_context yield) {
             f(yield);
-            std::lock_guard const lock{m_};
+            std::scoped_lock const lock{m_};
             if (--running_ == 0)
                 cv_.notify_all();
         },

include/xrpl/beast/unit_test/detail/const_container.h

@@ -25,7 +25,7 @@ protected:
         return m_cont;
     }
 
-    cont_type const&
+    [[nodiscard]] cont_type const&
     cont() const
     {
         return m_cont;
@@ -39,14 +39,14 @@ public:
     using const_iterator = typename cont_type::const_iterator;
 
     /** Returns `true` if the container is empty. */
-    bool
+    [[nodiscard]] bool
     empty() const
     {
         return m_cont.empty();
     }
 
     /** Returns the number of items in the container. */
-    size_type
+    [[nodiscard]] size_type
     size() const
     {
         return m_cont.size();
@@ -54,25 +54,25 @@ public:
 
     /** Returns forward iterators for traversal. */
     /** @{ */
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const
     {
         return m_cont.cbegin();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const
     {
         return m_cont.cbegin();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const
     {
         return m_cont.cend();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const
     {
         return m_cont.cend();

include/xrpl/beast/unit_test/match.h

@@ -14,7 +14,7 @@ namespace beast::unit_test {
 class selector
 {
 public:
-    enum mode_t {
+    enum class mode_t {
         // Run all tests except manual ones
         all,
 
@@ -53,8 +53,8 @@ public:
 template <class>
 selector::selector(mode_t mode, std::string const& pattern) : mode_(mode), pat_(pattern)
 {
-    if (mode_ == automatch && pattern.empty())
-        mode_ = all;
+    if (mode_ == mode_t::automatch && pattern.empty())
+        mode_ = mode_t::all;
 }
 
 template <class>
@@ -63,18 +63,18 @@ selector::operator()(suite_info const& s)
 {
     switch (mode_)
     {
-        case automatch:
+        case mode_t::automatch:
             // suite or full name
             if (s.name() == pat_ || s.full_name() == pat_)
             {
-                mode_ = none;
+                mode_ = mode_t::none;
                 return true;
             }
 
             // check module
             if (pat_ == s.module())
             {
-                mode_ = module;
+                mode_ = mode_t::module;
                 library_ = s.library();
                 return !s.manual();
             }
@@ -82,7 +82,7 @@ selector::operator()(suite_info const& s)
             // check library
             if (pat_ == s.library())
             {
-                mode_ = library;
+                mode_ = mode_t::library;
                 return !s.manual();
             }
 
@@ -96,19 +96,19 @@ selector::operator()(suite_info const& s)
 
             return false;
 
-        case suite:
+        case mode_t::suite:
             return pat_ == s.name();
 
-        case module:
+        case mode_t::module:
             return pat_ == s.module() && !s.manual();
 
-        case library:
+        case mode_t::library:
             return pat_ == s.library() && !s.manual();
 
-        case none:
+        case mode_t::none:
             return false;
 
-        case all:
+        case mode_t::all:
         default:
             break;
     };
@@ -138,28 +138,28 @@ selector::operator()(suite_info const& s)
 inline selector
 match_auto(std::string const& name)
 {
-    return selector(selector::automatch, name);
+    return selector(selector::mode_t::automatch, name);
 }
 
 /** Return a predicate that matches all suites not marked manual. */
 inline selector
 match_all()
 {
-    return selector(selector::all);
+    return selector(selector::mode_t::all);
 }
 
 /** Returns a predicate that matches a specific suite. */
 inline selector
 match_suite(std::string const& name)
 {
-    return selector(selector::suite, name);
+    return selector(selector::mode_t::suite, name);
 }
 
 /** Returns a predicate that matches all suites in a library. */
 inline selector
 match_library(std::string const& name)
 {
-    return selector(selector::library, name);
+    return selector(selector::mode_t::library, name);
 }
 
 }  // namespace beast::unit_test

include/xrpl/beast/unit_test/recorder.h

@@ -21,7 +21,7 @@ public:
     recorder() = default;
 
     /** Returns a report with the results of all completed suites. */
-    results const&
+    [[nodiscard]] results const&
     report() const
     {
         return m_results;

include/xrpl/beast/unit_test/reporter.h

@@ -62,6 +62,8 @@ private:
     {
         using run_time = std::pair<std::string, typename clock_type::duration>;
 
+        // Need to be named before converting
+        // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
         enum { max_top = 10 };
 
         std::size_t suites = 0;

include/xrpl/beast/unit_test/results.h

@@ -41,14 +41,14 @@ private:
         tests_t() = default;
 
         /** Returns the total number of test conditions. */
-        std::size_t
+        [[nodiscard]] std::size_t
         total() const
         {
             return cont().size();
         }
 
         /** Returns the number of failed test conditions. */
-        std::size_t
+        [[nodiscard]] std::size_t
         failed() const
         {
             return failed_;
@@ -89,7 +89,7 @@ public:
     }
 
     /** Returns the name of this testcase. */
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const
     {
         return name_;
@@ -118,21 +118,21 @@ public:
     }
 
     /** Returns the name of this suite. */
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const
     {
         return name_;
     }
 
     /** Returns the total number of test conditions. */
-    std::size_t
+    [[nodiscard]] std::size_t
     total() const
     {
         return total_;
     }
 
     /** Returns the number of failures. */
-    std::size_t
+    [[nodiscard]] std::size_t
     failed() const
     {
         return failed_;
@@ -173,21 +173,21 @@ public:
     results() = default;
 
     /** Returns the total number of test cases. */
-    std::size_t
+    [[nodiscard]] std::size_t
     cases() const
     {
         return m_cases;
     }
 
     /** Returns the total number of test conditions. */
-    std::size_t
+    [[nodiscard]] std::size_t
     total() const
     {
         return total_;
     }
 
     /** Returns the number of failures. */
-    std::size_t
+    [[nodiscard]] std::size_t
     failed() const
     {
         return failed_;

include/xrpl/beast/unit_test/runner.h

@@ -47,7 +47,7 @@ public:
     }
 
     /** Returns the argument string. */
-    std::string const&
+    [[nodiscard]] std::string const&
     arg() const
     {
         return arg_;
@@ -231,7 +231,7 @@ template <class>
 void
 runner::testcase(std::string const& name)
 {
-    std::lock_guard const lock(mutex_);
+    std::scoped_lock const lock(mutex_);
     // Name may not be empty
     BOOST_ASSERT(default_ || !name.empty());
     // Forgot to call pass or fail
@@ -247,7 +247,7 @@ template <class>
 void
 runner::pass()
 {
-    std::lock_guard const lock(mutex_);
+    std::scoped_lock const lock(mutex_);
     if (default_)
         testcase("");
     on_pass();
@@ -258,7 +258,7 @@ template <class>
 void
 runner::fail(std::string const& reason)
 {
-    std::lock_guard const lock(mutex_);
+    std::scoped_lock const lock(mutex_);
     if (default_)
         testcase("");
     on_fail(reason);
@@ -270,7 +270,7 @@ template <class>
 void
 runner::log(std::string const& s)
 {
-    std::lock_guard const lock(mutex_);
+    std::scoped_lock const lock(mutex_);
     if (default_)
         testcase("");
     on_log(s);

include/xrpl/beast/unit_test/suite.h

@@ -37,7 +37,7 @@ make_reason(String const& reason, char const* file, int line)
 
 class Thread;
 
-enum abort_t { no_abort_on_fail, abort_on_fail };
+enum class abort_t { no_abort_on_fail, abort_on_fail };
 
 /** A testsuite class.
 
@@ -57,7 +57,7 @@ private:
     // in the event of a failure, if the option to stop is set.
     struct abort_exception : public std::exception
     {
-        char const*
+        [[nodiscard]] char const*
         what() const noexcept override
         {
             return "test suite aborted";
@@ -127,7 +127,7 @@ private:
             @param abort Determines if suite continues running after a failure.
         */
         void
-        operator()(std::string const& name, abort_t abort = no_abort_on_fail);
+        operator()(std::string const& name, abort_t abort = abort_t::no_abort_on_fail);
 
         scoped_testcase
         operator()(abort_t abort);
@@ -363,14 +363,14 @@ public:
 inline void
 suite::testcase_t::operator()(std::string const& name, abort_t abort)
 {
-    suite_.abort_ = abort == abort_on_fail;
+    suite_.abort_ = abort == abort_t::abort_on_fail;
     suite_.runner_->testcase(name);
 }
 
 inline suite::scoped_testcase
 suite::testcase_t::operator()(abort_t abort)
 {
-    suite_.abort_ = abort == abort_on_fail;
+    suite_.abort_ = abort == abort_t::abort_on_fail;
     return {suite_, ss_};
 }
 

include/xrpl/beast/unit_test/suite_info.h

@@ -42,33 +42,33 @@ public:
     {
     }
 
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const
     {
         return name_;
     }
 
-    std::string const&
+    [[nodiscard]] std::string const&
     module() const
     {
         return module_;
     }
 
-    std::string const&
+    [[nodiscard]] std::string const&
     library() const
     {
         return library_;
     }
 
     /// Returns `true` if this suite only runs manually.
-    bool
+    [[nodiscard]] bool
     manual() const
     {
         return manual_;
     }
 
     /// Return the canonical suite name as a string.
-    std::string
+    [[nodiscard]] std::string
     full_name() const
     {
         return library_ + "." + module_ + "." + name_;

include/xrpl/beast/unit_test/thread.h

@@ -47,13 +47,13 @@ public:
         t_ = std::thread(&Thread::run, this, std::move(b));
     }
 
-    bool
+    [[nodiscard]] bool
     joinable() const
     {
         return t_.joinable();
     }
 
-    std::thread::id
+    [[nodiscard]] std::thread::id
     get_id() const
     {
         return t_.get_id();

include/xrpl/beast/utility/Journal.h

@@ -9,6 +9,8 @@ namespace beast {
 /** A namespace for easy access to logging severity values. */
 namespace severities {
 /** Severity level / threshold of a Journal message. */
+// Hundreds of usages via logging macros
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum Severity {
     kAll = 0,
 
@@ -66,12 +68,12 @@ public:
         operator=(Sink const& lhs) = delete;
 
         /** Returns `true` if text at the passed severity produces output. */
-        virtual bool
+        [[nodiscard]] virtual bool
         active(Severity level) const;
 
         /** Returns `true` if a message is also written to the Output Window
          * (MSVC). */
-        virtual bool
+        [[nodiscard]] virtual bool
         console() const;
 
         /** Set whether messages are also written to the Output Window (MSVC).
@@ -80,7 +82,7 @@ public:
         console(bool output);
 
         /** Returns the minimum severity level this sink will report. */
-        virtual Severity
+        [[nodiscard]] virtual Severity
         threshold() const;
 
         /** Set the minimum severity this sink will report. */
@@ -204,14 +206,14 @@ public:
         operator=(Stream const& other) = delete;
 
         /** Returns the Sink that this Stream writes to. */
-        Sink&
+        [[nodiscard]] Sink&
         sink() const
         {
             return m_sink;
         }
 
         /** Returns the Severity level of messages this Stream reports. */
-        Severity
+        [[nodiscard]] Severity
         level() const
         {
             return m_level;
@@ -219,7 +221,7 @@ public:
 
         /** Returns `true` if sink logs anything at this stream's level. */
         /** @{ */
-        bool
+        [[nodiscard]] bool
         active() const
         {
             return m_sink.active(m_level);
@@ -267,14 +269,14 @@ public:
     }
 
     /** Returns the Sink associated with this Journal. */
-    Sink&
+    [[nodiscard]] Sink&
     sink() const
     {
         return *m_sink;
     }
 
     /** Returns a stream for this sink, with the specified severity level. */
-    Stream
+    [[nodiscard]] Stream
     stream(Severity level) const
     {
         return Stream(*m_sink, level);
@@ -284,7 +286,7 @@ public:
         For a message to be logged, the severity must be at or above the
         sink's severity threshold.
     */
-    bool
+    [[nodiscard]] bool
     active(Severity level) const
     {
         return m_sink->active(level);
@@ -292,37 +294,37 @@ public:
 
     /** Severity stream access functions. */
     /** @{ */
-    Stream
+    [[nodiscard]] Stream
     trace() const
     {
         return {*m_sink, severities::kTrace};
     }
 
-    Stream
+    [[nodiscard]] Stream
     debug() const
     {
         return {*m_sink, severities::kDebug};
     }
 
-    Stream
+    [[nodiscard]] Stream
     info() const
     {
         return {*m_sink, severities::kInfo};
     }
 
-    Stream
+    [[nodiscard]] Stream
     warn() const
     {
         return {*m_sink, severities::kWarning};
     }
 
-    Stream
+    [[nodiscard]] Stream
     error() const
     {
         return {*m_sink, severities::kError};
     }
 
-    Stream
+    [[nodiscard]] Stream
     fatal() const
     {
         return {*m_sink, severities::kFatal};

include/xrpl/beast/utility/PropertyStream.h

@@ -149,7 +149,7 @@ class PropertyStream::Item : public List<Item>::Node
 {
 public:
     explicit Item(Source* source);
-    Source&
+    [[nodiscard]] Source&
     source() const;
     Source*
     operator->() const;
@@ -217,7 +217,7 @@ public:
 
     PropertyStream&
     stream();
-    PropertyStream const&
+    [[nodiscard]] PropertyStream const&
     stream() const;
 
     template <typename Value>
@@ -287,7 +287,7 @@ public:
 
     PropertyStream&
     stream();
-    PropertyStream const&
+    [[nodiscard]] PropertyStream const&
     stream() const;
 
     template <typename Value>
@@ -323,7 +323,7 @@ public:
     operator=(Source const&) = delete;
 
     /** Returns the name of this source. */
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const;
 
     /** Add a child source. */

include/xrpl/beast/utility/WrappedSink.h

@@ -35,13 +35,13 @@ public:
         prefix_ = s;
     }
 
-    bool
+    [[nodiscard]] bool
     active(beast::severities::Severity level) const override
     {
         return sink_.active(level);
     }
 
-    bool
+    [[nodiscard]] bool
     console() const override
     {
         return sink_.console();
@@ -53,7 +53,7 @@ public:
         sink_.console(output);
     }
 
-    beast::severities::Severity
+    [[nodiscard]] beast::severities::Severity
     threshold() const override
     {
         return sink_.threshold();

include/xrpl/beast/utility/temp_dir.h

@@ -43,7 +43,7 @@ public:
     }
 
     /// Get the native path for the temporary directory
-    std::string
+    [[nodiscard]] std::string
     path() const
     {
         return path_.string();
@@ -53,7 +53,7 @@ public:
 
         The file does not need to exist.
     */
-    std::string
+    [[nodiscard]] std::string
     file(std::string const& name) const
     {
         return (path_ / name).string();

include/xrpl/conditions/Fulfillment.h

@@ -41,15 +41,15 @@ public:
         with respect to other conditions of the
         same type.
    */
-    virtual Buffer
+    [[nodiscard]] virtual Buffer
     fingerprint() const = 0;
 
     /** Returns the type of this condition. */
-    virtual Type
+    [[nodiscard]] virtual Type
     type() const = 0;
 
     /** Validates a fulfillment. */
-    virtual bool
+    [[nodiscard]] virtual bool
     validate(Slice data) const = 0;
 
     /** Calculates the cost associated with this fulfillment. *
@@ -58,7 +58,7 @@ public:
         type and properties of the condition and the fulfillment
         that the condition is generated from.
     */
-    virtual std::uint32_t
+    [[nodiscard]] virtual std::uint32_t
     cost() const = 0;
 
     /** Returns the condition associated with the given fulfillment.
@@ -67,7 +67,7 @@ public:
         will, if compliant, produce the identical condition for the
         same fulfillment.
     */
-    virtual Condition
+    [[nodiscard]] virtual Condition
     condition() const = 0;
 };
 

include/xrpl/conditions/detail/PreimageSha256.h

@@ -90,13 +90,13 @@ public:
     {
     }
 
-    Type
+    [[nodiscard]] Type
     type() const override
     {
         return Type::preimageSha256;
     }
 
-    Buffer
+    [[nodiscard]] Buffer
     fingerprint() const override
     {
         sha256_hasher h;
@@ -105,19 +105,19 @@ public:
         return {d.data(), d.size()};
     }
 
-    std::uint32_t
+    [[nodiscard]] std::uint32_t
     cost() const override
     {
         return static_cast<std::uint32_t>(payload_.size());
     }
 
-    Condition
+    [[nodiscard]] Condition
     condition() const override
     {
         return {type(), cost(), fingerprint()};
     }
 
-    bool
+    [[nodiscard]] bool
     validate(Slice) const override
     {
         // Perhaps counterintuitively, the message isn't

include/xrpl/core/ClosureCounter.h

@@ -56,7 +56,7 @@ private:
         // a lock.  This removes a small timing window that occurs if the
         // waiting thread is handling a spurious wakeup when closureCount_
         // drops to zero.
-        std::lock_guard const lock{mutex_};
+        std::scoped_lock const lock{mutex_};
 
         // Update closureCount_.  Notify if stopping and closureCount_ == 0.
         if ((--closureCount_ == 0) && waitForClosures_)
@@ -170,7 +170,7 @@ public:
     {
         std::optional<Substitute<Closure>> ret;
 
-        std::lock_guard const lock{mutex_};
+        std::scoped_lock const lock{mutex_};
         if (!waitForClosures_)
             ret.emplace(*this, std::forward<Closure>(closure));
 
@@ -193,7 +193,7 @@ public:
     bool
     joined() const
     {
-        std::lock_guard const lock{mutex_};
+        std::scoped_lock const lock{mutex_};
         return waitForClosures_;
     }
 };

include/xrpl/core/Coro.ipp

@@ -34,7 +34,7 @@ inline void
 JobQueue::Coro::yield() const
 {
     {
-        std::lock_guard lock(jq_.m_mutex);
+        std::scoped_lock lock(jq_.m_mutex);
         ++jq_.nSuspend_;
     }
     (*yield_)();
@@ -44,7 +44,7 @@ inline bool
 JobQueue::Coro::post()
 {
     {
-        std::lock_guard lk(mutex_run_);
+        std::scoped_lock lk(mutex_run_);
         running_ = true;
     }
 
@@ -55,7 +55,7 @@ JobQueue::Coro::post()
     }
 
     // The coroutine will not run.  Clean up running_.
-    std::lock_guard lk(mutex_run_);
+    std::scoped_lock lk(mutex_run_);
     running_ = false;
     cv_.notify_all();
     return false;
@@ -65,16 +65,16 @@ inline void
 JobQueue::Coro::resume()
 {
     {
-        std::lock_guard lk(mutex_run_);
+        std::scoped_lock lk(mutex_run_);
         running_ = true;
     }
     {
-        std::lock_guard lk(jq_.m_mutex);
+        std::scoped_lock lk(jq_.m_mutex);
         --jq_.nSuspend_;
     }
     auto saved = detail::getLocalValues().release();
     detail::getLocalValues().reset(&lvs_);
-    std::lock_guard lock(mutex_);
+    std::scoped_lock lock(mutex_);
     // A late resume() can arrive after the coroutine has already completed.
     // This is an expected (if rare) outcome of the race condition documented
     // in JobQueue.h:354-377 where post() schedules a resume job before the
@@ -89,7 +89,7 @@ JobQueue::Coro::resume()
     }
     detail::getLocalValues().release();
     detail::getLocalValues().reset(saved);
-    std::lock_guard lk(mutex_run_);
+    std::scoped_lock lk(mutex_run_);
     running_ = false;
     cv_.notify_all();
 }
@@ -113,7 +113,7 @@ JobQueue::Coro::expectEarlyExit()
         //
         // That said, since we're outside the Coro's stack, we need to
         // decrement the nSuspend that the Coro's call to yield caused.
-        std::lock_guard lock(jq_.m_mutex);
+        std::scoped_lock lock(jq_.m_mutex);
         --jq_.nSuspend_;
 #ifndef NDEBUG
         finished_ = true;

include/xrpl/core/HashRouter.h

@@ -118,7 +118,7 @@ private:
                 peers_.insert(peer);
         }
 
-        HashRouterFlags
+        [[nodiscard]] HashRouterFlags
         getFlags(void) const
         {
             return flags_;
@@ -138,7 +138,7 @@ private:
         }
 
         /** Return seated relay time point if the message has been relayed */
-        std::optional<Stopwatch::time_point>
+        [[nodiscard]] std::optional<Stopwatch::time_point>
         relayed() const
         {
             return relayed_;

include/xrpl/core/Job.h

@@ -11,6 +11,8 @@ namespace xrpl {
 // Note that this queue should only be used for CPU-bound jobs
 // It is primarily intended for signature checking
 
+// Protocol-wide
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum JobType {
     // Special type indicating an invalid job - will go away soon.
     jtINVALID = -1,
@@ -98,11 +100,11 @@ public:
         LoadMonitor& lm,
         std::function<void()> const& job);
 
-    JobType
+    [[nodiscard]] JobType
     getType() const;
 
     /** Returns the time when the job was queued. */
-    clock_type::time_point const&
+    [[nodiscard]] clock_type::time_point const&
     queue_time() const;
 
     void

include/xrpl/core/JobQueue.h

@@ -7,8 +7,13 @@
 #include <xrpl/core/detail/Workers.h>
 #include <xrpl/json/json_value.h>
 
+// Include only the specific Boost.Coroutine2 headers actually used here.
+// Avoid `boost/coroutine2/all.hpp` because it transitively pulls in
+// `boost/context/pooled_fixedsize_stack.hpp`, whose `.malloc()` / `.free()`
+// member calls on `boost::pool` collide with MSVC's `_CRTDBG_MAP_ALLOC` macros
+// in Debug builds (see cmake/XrplCompiler.cmake).
 #include <boost/context/protected_fixedsize_stack.hpp>
-#include <boost/coroutine2/all.hpp>
+#include <boost/coroutine2/coroutine.hpp>
 
 #include <set>
 

include/xrpl/core/JobTypeData.h

@@ -54,13 +54,13 @@ public:
     JobTypeData&
     operator=(JobTypeData const& other) = delete;
 
-    std::string
+    [[nodiscard]] std::string
     name() const
     {
         return info.name();
     }
 
-    JobType
+    [[nodiscard]] JobType
     type() const
     {
         return info.type();

include/xrpl/core/JobTypeInfo.h

@@ -40,37 +40,37 @@ public:
     {
     }
 
-    JobType
+    [[nodiscard]] JobType
     type() const
     {
         return m_type;
     }
 
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const
     {
         return m_name;
     }
 
-    int
+    [[nodiscard]] int
     limit() const
     {
         return m_limit;
     }
 
-    bool
+    [[nodiscard]] bool
     special() const
     {
         return m_limit == 0;
     }
 
-    std::chrono::milliseconds
+    [[nodiscard]] std::chrono::milliseconds
     getAverageLatency() const
     {
         return m_avgLatency;
     }
 
-    std::chrono::milliseconds
+    [[nodiscard]] std::chrono::milliseconds
     getPeakLatency() const
     {
         return m_peakLatency;

include/xrpl/core/JobTypes.h

@@ -113,7 +113,7 @@ public:
         return instance().get(jt).name();
     }
 
-    JobTypeInfo const&
+    [[nodiscard]] JobTypeInfo const&
     get(JobType jt) const
     {
         Map::const_iterator const iter(m_map.find(jt));
@@ -125,37 +125,37 @@ public:
         return m_unknown;
     }
 
-    JobTypeInfo const&
+    [[nodiscard]] JobTypeInfo const&
     getInvalid() const
     {
         return m_unknown;
     }
 
-    Map::size_type
+    [[nodiscard]] Map::size_type
     size() const
     {
         return m_map.size();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const
     {
         return m_map.cbegin();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cbegin() const
     {
         return m_map.cbegin();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const
     {
         return m_map.cend();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     cend() const
     {
         return m_map.cend();

include/xrpl/core/LoadEvent.h

@@ -21,15 +21,15 @@ public:
 
     ~LoadEvent();
 
-    std::string const&
+    [[nodiscard]] std::string const&
     name() const;
 
     // The time spent waiting.
-    std::chrono::steady_clock::duration
+    [[nodiscard]] std::chrono::steady_clock::duration
     waitTime() const;
 
     // The time spent running.
-    std::chrono::steady_clock::duration
+    [[nodiscard]] std::chrono::steady_clock::duration
     runTime() const;
 
     void

include/xrpl/core/NetworkIDService.h

@@ -26,7 +26,7 @@ public:
      *
      * @return The network ID this server is configured for
      */
-    virtual std::uint32_t
+    [[nodiscard]] virtual std::uint32_t
     getNetworkID() const noexcept = 0;
 };
 

include/xrpl/core/PeerReservationTable.h

@@ -22,7 +22,7 @@ public:
     PublicKey nodeId;
     std::string description = {};  // NOLINT(readability-redundant-member-init)
 
-    auto
+    [[nodiscard]] auto
     toJson() const -> Json::Value;
 
     template <typename Hasher>
@@ -67,7 +67,7 @@ public:
     bool
     contains(PublicKey const& nodeId)
     {
-        std::lock_guard const lock(this->mutex_);
+        std::scoped_lock const lock(this->mutex_);
         return table_.contains({.nodeId = nodeId, .description = {}});
     }
 

include/xrpl/core/PerfLog.h

@@ -121,7 +121,7 @@ public:
      *
      * @return Counters Json object
      */
-    virtual Json::Value
+    [[nodiscard]] virtual Json::Value
     countersJson() const = 0;
 
     /**
@@ -129,7 +129,7 @@ public:
      *
      * @return Current executing jobs and RPC calls and durations
      */
-    virtual Json::Value
+    [[nodiscard]] virtual Json::Value
     currentJson() const = 0;
 
     /**

include/xrpl/core/ServiceRegistry.h

@@ -192,7 +192,7 @@ public:
     virtual OpenLedger&
     getOpenLedger() = 0;
 
-    virtual OpenLedger const&
+    [[nodiscard]] virtual OpenLedger const&
     getOpenLedger() const = 0;
 
     // Transaction and operation services
@@ -219,7 +219,7 @@ public:
     getPerfLog() = 0;
 
     // Configuration and state
-    virtual bool
+    [[nodiscard]] virtual bool
     isStopping() const = 0;
 
     virtual beast::Journal
@@ -231,7 +231,7 @@ public:
     virtual Logs&
     getLogs() = 0;
 
-    virtual std::optional<uint256> const&
+    [[nodiscard]] virtual std::optional<uint256> const&
     getTrapTxID() const = 0;
 
     /** Retrieve the "wallet database" */

include/xrpl/core/detail/Workers.h

@@ -106,7 +106,7 @@ public:
 
         @note This function is not thread-safe.
     */
-    int
+    [[nodiscard]] int
     getNumberOfThreads() const noexcept;
 
     /** Set the desired number of threads.
@@ -141,7 +141,7 @@ public:
         While this function is thread-safe, the value may not stay
         accurate for very long. It's mainly for diagnostic purposes.
     */
-    int
+    [[nodiscard]] int
     numberOfCurrentlyRunningTasks() const noexcept;
 
     //--------------------------------------------------------------------------

include/xrpl/core/detail/semaphore.h

@@ -55,7 +55,7 @@ public:
     void
     notify()
     {
-        std::lock_guard const lock{m_mutex};
+        std::scoped_lock const lock{m_mutex};
         ++m_count;
         m_cond.notify_one();
     }
@@ -76,7 +76,7 @@ public:
     bool
     try_wait()
     {
-        std::lock_guard lock{m_mutex};
+        std::scoped_lock lock{m_mutex};
         if (m_count == 0)
             return false;
         --m_count;

include/xrpl/json/JsonPropertyStream.h

@@ -14,7 +14,7 @@ public:
 
 public:
     JsonPropertyStream();
-    Json::Value const&
+    [[nodiscard]] Json::Value const&
     top() const;
 
 protected:

include/xrpl/json/Writer.h

@@ -107,7 +107,7 @@ namespace Json {
 class Writer
 {
 public:
-    enum CollectionType { array, object };
+    enum class CollectionType { array, object };
 
     explicit Writer(Output const& output);
     Writer(Writer&&) noexcept;

include/xrpl/json/json_reader.h

@@ -64,12 +64,14 @@ public:
      * their location in the parsed document. An empty string is returned if no
      * error occurred during parsing.
      */
-    std::string
+    [[nodiscard]] std::string
     getFormattedErrorMessages() const;
 
     static constexpr unsigned nest_limit{25};
 
 private:
+    // 53 files, protocol-wide
+    // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
     enum TokenType {
         tokenEndOfStream = 0,
         tokenObjectBegin,

include/xrpl/json/json_value.h

@@ -15,6 +15,8 @@ namespace Json {
 
 /** \brief Type of the value held by a Value object.
  */
+// Used throughout JSON layer
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum ValueType {
     nullValue = 0,  ///< 'null' value
     intValue,       ///< signed integer value
@@ -53,7 +55,7 @@ public:
         return str_;
     }
 
-    constexpr char const*
+    [[nodiscard]] constexpr char const*
     c_str() const
     {
         return str_;
@@ -147,6 +149,8 @@ private:
     class CZString
     {
     public:
+        // Stored as int field, implicit conversion
+        // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
         enum DuplicationPolicy { noDuplication = 0, duplicate, duplicateOnCopy };
         CZString(int index);
         CZString(char const* cstr, DuplicationPolicy allocate);
@@ -158,11 +162,11 @@ private:
         operator<(CZString const& other) const;
         bool
         operator==(CZString const& other) const;
-        int
+        [[nodiscard]] int
         index() const;
-        char const*
+        [[nodiscard]] char const*
         c_str() const;
-        bool
+        [[nodiscard]] bool
         isStaticString() const;
 
     private:
@@ -223,60 +227,60 @@ public:
     void
     swap(Value& other) noexcept;
 
-    ValueType
+    [[nodiscard]] ValueType
     type() const;
 
-    char const*
+    [[nodiscard]] char const*
     asCString() const;
     /** Returns the unquoted string value. */
-    std::string
+    [[nodiscard]] std::string
     asString() const;
-    Int
+    [[nodiscard]] Int
     asInt() const;
-    UInt
+    [[nodiscard]] UInt
     asUInt() const;
-    double
+    [[nodiscard]] double
     asDouble() const;
-    bool
+    [[nodiscard]] bool
     asBool() const;
 
     /** Correct absolute value from int or unsigned int */
-    UInt
+    [[nodiscard]] UInt
     asAbsUInt() const;
 
     // TODO: What is the "empty()" method this docstring mentions?
     /** isNull() tests to see if this field is null.  Don't use this method to
         test for emptiness: use empty(). */
-    bool
+    [[nodiscard]] bool
     isNull() const;
-    bool
+    [[nodiscard]] bool
     isBool() const;
-    bool
+    [[nodiscard]] bool
     isInt() const;
-    bool
+    [[nodiscard]] bool
     isUInt() const;
-    bool
+    [[nodiscard]] bool
     isIntegral() const;
-    bool
+    [[nodiscard]] bool
     isDouble() const;
-    bool
+    [[nodiscard]] bool
     isNumeric() const;
-    bool
+    [[nodiscard]] bool
     isString() const;
-    bool
+    [[nodiscard]] bool
     isArray() const;
-    bool
+    [[nodiscard]] bool
     isArrayOrNull() const;
-    bool
+    [[nodiscard]] bool
     isObject() const;
-    bool
+    [[nodiscard]] bool
     isObjectOrNull() const;
 
-    bool
+    [[nodiscard]] bool
     isConvertibleTo(ValueType other) const;
 
     /// Number of values in array or object
-    UInt
+    [[nodiscard]] UInt
     size() const;
 
     /** Returns false if this is an empty array, empty object, empty string,
@@ -304,10 +308,10 @@ public:
     operator[](UInt index) const;
     /// If the array contains at least index+1 elements, returns the element
     /// value, otherwise returns defaultValue.
-    Value
+    [[nodiscard]] Value
     get(UInt index, Value const& defaultValue) const;
     /// Return true if index < size().
-    bool
+    [[nodiscard]] bool
     isValidIndex(UInt index) const;
     /// \brief Append value to array at the end.
     ///
@@ -355,7 +359,7 @@ public:
     Value
     get(char const* key, Value const& defaultValue) const;
     /// Return the member named key if it exist, defaultValue otherwise.
-    Value
+    [[nodiscard]] Value
     get(std::string const& key, Value const& defaultValue) const;
 
     /// \brief Remove and return the named member.
@@ -374,10 +378,10 @@ public:
     bool
     isMember(char const* key) const;
     /// Return true if the object has a member named key.
-    bool
+    [[nodiscard]] bool
     isMember(std::string const& key) const;
     /// Return true if the object has a member named key.
-    bool
+    [[nodiscard]] bool
     isMember(StaticString const& key) const;
 
     /// \brief Return a list of the member names.
@@ -385,15 +389,15 @@ public:
     /// If null, return an empty list.
     /// \pre type() is objectValue or nullValue
     /// \post if type() was nullValue, it remains nullValue
-    Members
+    [[nodiscard]] Members
     getMemberNames() const;
 
-    std::string
+    [[nodiscard]] std::string
     toStyledString() const;
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const;
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const;
 
     iterator
@@ -471,6 +475,8 @@ operator>=(Value const& x, Value const& y)
 class ValueAllocator
 {
 public:
+    // Need to be named before converting
+    // NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
     enum { unknown = (unsigned)-1 };
 
     virtual ~ValueAllocator() = default;
@@ -513,20 +519,20 @@ public:
 
     /// Return either the index or the member name of the referenced value as a
     /// Value.
-    Value
+    [[nodiscard]] Value
     key() const;
 
     /// Return the index of the referenced Value. -1 if it is not an arrayValue.
-    UInt
+    [[nodiscard]] UInt
     index() const;
 
     /// Return the member name of the referenced Value. "" if it is not an
     /// objectValue.
-    char const*
+    [[nodiscard]] char const*
     memberName() const;
 
 protected:
-    Value&
+    [[nodiscard]] Value&
     deref() const;
 
     void
@@ -535,10 +541,10 @@ protected:
     void
     decrement();
 
-    difference_type
+    [[nodiscard]] difference_type
     computeDistance(SelfType const& other) const;
 
-    bool
+    [[nodiscard]] bool
     isEqual(SelfType const& other) const;
 
     void

include/xrpl/ledger/AcceptedLedgerTx.h

@@ -30,47 +30,47 @@ public:
         std::shared_ptr<STTx const> const&,
         std::shared_ptr<STObject const> const&);
 
-    std::shared_ptr<STTx const> const&
+    [[nodiscard]] std::shared_ptr<STTx const> const&
     getTxn() const
     {
         return mTxn;
     }
-    TxMeta const&
+    [[nodiscard]] TxMeta const&
     getMeta() const
     {
         return mMeta;
     }
 
-    boost::container::flat_set<AccountID> const&
+    [[nodiscard]] boost::container::flat_set<AccountID> const&
     getAffected() const
     {
         return mAffected;
     }
 
-    TxID
+    [[nodiscard]] TxID
     getTransactionID() const
     {
         return mTxn->getTransactionID();
     }
-    TxType
+    [[nodiscard]] TxType
     getTxnType() const
     {
         return mTxn->getTxnType();
     }
-    TER
+    [[nodiscard]] TER
     getResult() const
     {
         return mMeta.getResultTER();
     }
-    std::uint32_t
+    [[nodiscard]] std::uint32_t
     getTxnSeq() const
     {
         return mMeta.getIndex();
     }
-    std::string
+    [[nodiscard]] std::string
     getEscMeta() const;
 
-    Json::Value const&
+    [[nodiscard]] Json::Value const&
     getJson() const
     {
         return mJson;

include/xrpl/ledger/AmendmentTable.h

@@ -36,7 +36,7 @@ public:
 
     virtual ~AmendmentTable() = default;
 
-    virtual uint256
+    [[nodiscard]] virtual uint256
     find(std::string const& name) const = 0;
 
     virtual bool
@@ -47,9 +47,9 @@ public:
     virtual bool
     enable(uint256 const& amendment) = 0;
 
-    virtual bool
+    [[nodiscard]] virtual bool
     isEnabled(uint256 const& amendment) const = 0;
-    virtual bool
+    [[nodiscard]] virtual bool
     isSupported(uint256 const& amendment) const = 0;
 
     /**
@@ -58,17 +58,17 @@ public:
      *
      * @return true if an unsupported feature is enabled on the network
      */
-    virtual bool
+    [[nodiscard]] virtual bool
     hasUnsupportedEnabled() const = 0;
 
-    virtual std::optional<NetClock::time_point>
+    [[nodiscard]] virtual std::optional<NetClock::time_point>
     firstUnsupportedExpected() const = 0;
 
-    virtual Json::Value
+    [[nodiscard]] virtual Json::Value
     getJson(bool isAdmin) const = 0;
 
     /** Returns a Json::objectValue. */
-    virtual Json::Value
+    [[nodiscard]] virtual Json::Value
     getJson(uint256 const& amendment, bool isAdmin) const = 0;
 
     /** Called when a new fully-validated ledger is accepted. */
@@ -87,7 +87,7 @@ public:
     /** Called to determine whether the amendment logic needs to process
         a new validated ledger. (If it could have changed things.)
     */
-    virtual bool
+    [[nodiscard]] virtual bool
     needValidatedLedger(LedgerIndex seq) const = 0;
 
     virtual void
@@ -112,14 +112,14 @@ public:
 
     // Called by the consensus code when we need to
     // add feature entries to a validation
-    virtual std::vector<uint256>
+    [[nodiscard]] virtual std::vector<uint256>
     doValidation(std::set<uint256> const& enabled) const = 0;
 
     // The set of amendments to enable in the genesis ledger
     // This will return all known, non-vetoed amendments.
     // If we ever have two amendments that should not both be
     // enabled at the same time, we should ensure one is vetoed.
-    virtual std::vector<uint256>
+    [[nodiscard]] virtual std::vector<uint256>
     getDesired() const = 0;
 
     // The function below adapts the API callers expect to the

include/xrpl/ledger/ApplyView.h

@@ -7,6 +7,8 @@
 
 namespace xrpl {
 
+// Bitwise flag enum with existing operator overloads
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum ApplyFlags : std::uint32_t {
     tapNONE = 0x00,
 
@@ -134,7 +136,7 @@ public:
         while transactions applied to the consensus
         ledger produce hard failures (and claim a fee).
     */
-    virtual ApplyFlags
+    [[nodiscard]] virtual ApplyFlags
     flags() const = 0;
 
     /** Prepare to modify the SLE associated with key.

include/xrpl/ledger/BookDirs.h

@@ -22,10 +22,10 @@ public:
 
     BookDirs(ReadView const&, Book const&);
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const;
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const;
 };
 

include/xrpl/ledger/CanonicalTXSet.h

@@ -59,13 +59,13 @@ private:
             return !(lhs == rhs);
         }
 
-        uint256 const&
+        [[nodiscard]] uint256 const&
         getAccount() const
         {
             return account_;
         }
 
-        uint256 const&
+        [[nodiscard]] uint256 const&
         getTXID() const
         {
             return txId_;
@@ -118,30 +118,30 @@ public:
         return map_.erase(it);
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const
     {
         return map_.begin();
     }
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const
     {
         return map_.end();
     }
 
-    size_t
+    [[nodiscard]] size_t
     size() const
     {
         return map_.size();
     }
-    bool
+    [[nodiscard]] bool
     empty() const
     {
         return map_.empty();
     }
 
-    uint256 const&
+    [[nodiscard]] uint256 const&
     key() const
     {
         return salt_;

include/xrpl/ledger/Dir.h

@@ -31,10 +31,10 @@ public:
 
     Dir(ReadView const&, Keylet const&);
 
-    const_iterator
+    [[nodiscard]] const_iterator
     begin() const;
 
-    const_iterator
+    [[nodiscard]] const_iterator
     end() const;
 };
 

include/xrpl/ledger/PaymentSandbox.h

@@ -21,9 +21,8 @@ private:
     struct ValueIOU
     {
         explicit ValueIOU() = default;
-
-        STAmount lowAcctCredits;
-        STAmount highAcctCredits;
+        STAmount lowAcctDebits;
+        STAmount highAcctDebits;
         STAmount lowAcctOrigBalance;
     };
 
@@ -75,10 +74,10 @@ public:
 
     // Get the adjustments for the balance between main and other.
     // Returns the debits, credits and the original balance
-    std::optional<AdjustmentIOU>
+    [[nodiscard]] std::optional<AdjustmentIOU>
     adjustmentsIOU(AccountID const& main, AccountID const& other, Currency const& currency) const;
 
-    std::optional<AdjustmentMPT>
+    [[nodiscard]] std::optional<AdjustmentMPT>
     adjustmentsMPT(MPTID const& mptID) const;
 
     void
@@ -105,7 +104,7 @@ public:
     // Get the adjusted owner count. Since DeferredCredits is meant to be used
     // in payments, and payments only decrease owner counts, return the max
     // remembered owner count.
-    std::optional<std::uint32_t>
+    [[nodiscard]] std::optional<std::uint32_t>
     ownerCount(AccountID const& id) const;
 
     void
@@ -180,15 +179,15 @@ public:
     }
     /** @} */
 
-    STAmount
+    [[nodiscard]] STAmount
     balanceHookIOU(AccountID const& account, AccountID const& issuer, STAmount const& amount)
         const override;
 
-    STAmount
+    [[nodiscard]] STAmount
     balanceHookMPT(AccountID const& account, MPTIssue const& issue, std::int64_t amount)
         const override;
 
-    STAmount
+    [[nodiscard]] STAmount
     balanceHookSelfIssueMPT(MPTIssue const& issue, std::int64_t amount) const override;
 
     void
@@ -213,7 +212,7 @@ public:
     void
     adjustOwnerCountHook(AccountID const& account, std::uint32_t cur, std::uint32_t next) override;
 
-    std::uint32_t
+    [[nodiscard]] std::uint32_t
     ownerCountHook(AccountID const& account, std::uint32_t count) const override;
 
     /** Apply changes to base view.
@@ -230,14 +229,7 @@ public:
     apply(PaymentSandbox& to);
     /** @} */
 
-    // Return a map of balance changes on trust lines. The low account is the
-    // first account in the key. If the two accounts are equal, the map contains
-    // the total changes in currency regardless of issuer. This is useful to get
-    // the total change in XRP balances.
-    std::map<std::tuple<AccountID, AccountID, Currency>, STAmount>
-    balanceChanges(ReadView const& view) const;
-
-    XRPAmount
+    [[nodiscard]] XRPAmount
     xrpDestroyed() const;
 
 private:

include/xrpl/ledger/PendingSaves.h

@@ -31,7 +31,7 @@ public:
     bool
     startWork(LedgerIndex seq)
     {
-        std::lock_guard const lock(mutex_);
+        std::scoped_lock const lock(mutex_);
 
         auto it = map_.find(seq);
 
@@ -54,7 +54,7 @@ public:
     void
     finishWork(LedgerIndex seq)
     {
-        std::lock_guard const lock(mutex_);
+        std::scoped_lock const lock(mutex_);
 
         map_.erase(seq);
         await_.notify_all();
@@ -64,7 +64,7 @@ public:
     bool
     pending(LedgerIndex seq)
     {
-        std::lock_guard const lock(mutex_);
+        std::scoped_lock const lock(mutex_);
         return map_.contains(seq);
     }
 
@@ -117,7 +117,7 @@ public:
     std::map<LedgerIndex, bool>
     getSnapshot() const
     {
-        std::lock_guard const lock(mutex_);
+        std::scoped_lock const lock(mutex_);
 
         return map_;
     }

include/xrpl/ledger/ReadView.h

@@ -39,22 +39,22 @@ public:
     struct sles_type : detail::ReadViewFwdRange<std::shared_ptr<SLE const>>
     {
         explicit sles_type(ReadView const& view);
-        iterator
+        [[nodiscard]] iterator
         begin() const;
-        iterator
+        [[nodiscard]] iterator
         end() const;
-        iterator
+        [[nodiscard]] iterator
         upper_bound(key_type const& key) const;
     };
 
     struct txs_type : detail::ReadViewFwdRange<tx_type>
     {
         explicit txs_type(ReadView const& view);
-        bool
+        [[nodiscard]] bool
         empty() const;
-        iterator
+        [[nodiscard]] iterator
         begin() const;
-        iterator
+        [[nodiscard]] iterator
         end() const;
     };
 
@@ -78,33 +78,33 @@ public:
     }
 
     /** Returns information about the ledger. */
-    virtual LedgerHeader const&
+    [[nodiscard]] virtual LedgerHeader const&
     header() const = 0;
 
     /** Returns true if this reflects an open ledger. */
-    virtual bool
+    [[nodiscard]] virtual bool
     open() const = 0;
 
     /** Returns the close time of the previous ledger. */
-    NetClock::time_point
+    [[nodiscard]] NetClock::time_point
     parentCloseTime() const
     {
         return header().parentCloseTime;
     }
 
     /** Returns the sequence number of the base ledger. */
-    LedgerIndex
+    [[nodiscard]] LedgerIndex
     seq() const
     {
         return header().seq;
     }
 
     /** Returns the fees for the base ledger. */
-    virtual Fees const&
+    [[nodiscard]] virtual Fees const&
     fees() const = 0;
 
     /** Returns the tx processing rules. */
-    virtual Rules const&
+    [[nodiscard]] virtual Rules const&
     rules() const = 0;
 
     /** Determine if a state item exists.
@@ -114,7 +114,7 @@ public:
         @return `true` if a SLE is associated with the
                 specified key.
     */
-    virtual bool
+    [[nodiscard]] virtual bool
     exists(Keylet const& k) const = 0;
 
     /** Return the key of the next state item.
@@ -127,7 +127,7 @@ public:
         the key returned would be outside the open
         interval (key, last).
     */
-    virtual std::optional<key_type>
+    [[nodiscard]] virtual std::optional<key_type>
     succ(key_type const& key, std::optional<key_type> const& last = std::nullopt) const = 0;
 
     /** Return the state item associated with a key.
@@ -143,7 +143,7 @@ public:
         @return `nullptr` if the key is not present or
                 if the type does not match.
     */
-    virtual std::shared_ptr<SLE const>
+    [[nodiscard]] virtual std::shared_ptr<SLE const>
     read(Keylet const& k) const = 0;
 
     // Accounts in a payment are not allowed to use assets acquired during that
@@ -151,7 +151,7 @@ public:
     // changes that accounts make during a payment. `balanceHookIOU` adjusts
     // balances so newly acquired assets are not counted toward the balance.
     // This is required to support PaymentSandbox.
-    virtual STAmount
+    [[nodiscard]] virtual STAmount
     balanceHookIOU(AccountID const& account, AccountID const& issuer, STAmount const& amount) const
     {
         XRPL_ASSERT(amount.holds<Issue>(), "balanceHookIOU: amount is for Issue");
@@ -161,7 +161,7 @@ public:
 
     // balanceHookMPT adjusts balances so newly acquired assets are not counted
     // toward the balance.
-    virtual STAmount
+    [[nodiscard]] virtual STAmount
     balanceHookMPT(AccountID const& account, MPTIssue const& issue, std::int64_t amount) const
     {
         return STAmount{issue, amount};
@@ -171,7 +171,7 @@ public:
     // funds available to issue, which are originally available funds less
     // already self sold MPT amounts (MPT sell offer). This hook is used
     // by issuerFundsToSelfIssue() function.
-    virtual STAmount
+    [[nodiscard]] virtual STAmount
     balanceHookSelfIssueMPT(MPTIssue const& issue, std::int64_t amount) const
     {
         return STAmount{issue, amount};
@@ -182,30 +182,30 @@ public:
     // changes that accounts make during a payment. `ownerCountHook` adjusts the
     // ownerCount so it returns the max value of the ownerCount so far.
     // This is required to support PaymentSandbox.
-    virtual std::uint32_t
+    [[nodiscard]] virtual std::uint32_t
     ownerCountHook(AccountID const& account, std::uint32_t count) const
     {
         return count;
     }
 
     // used by the implementation
-    virtual std::unique_ptr<sles_type::iter_base>
+    [[nodiscard]] virtual std::unique_ptr<sles_type::iter_base>
     slesBegin() const = 0;
 
     // used by the implementation
-    virtual std::unique_ptr<sles_type::iter_base>
+    [[nodiscard]] virtual std::unique_ptr<sles_type::iter_base>
     slesEnd() const = 0;
 
     // used by the implementation
-    virtual std::unique_ptr<sles_type::iter_base>
+    [[nodiscard]] virtual std::unique_ptr<sles_type::iter_base>
     slesUpperBound(key_type const& key) const = 0;
 
     // used by the implementation
-    virtual std::unique_ptr<txs_type::iter_base>
+    [[nodiscard]] virtual std::unique_ptr<txs_type::iter_base>
     txsBegin() const = 0;
 
     // used by the implementation
-    virtual std::unique_ptr<txs_type::iter_base>
+    [[nodiscard]] virtual std::unique_ptr<txs_type::iter_base>
     txsEnd() const = 0;
 
     /** Returns `true` if a tx exists in the tx map.
@@ -213,7 +213,7 @@ public:
         A tx exists in the map if it is part of the
         base ledger, or if it is a newly inserted tx.
     */
-    virtual bool
+    [[nodiscard]] virtual bool
     txExists(key_type const& key) const = 0;
 
     /** Read a transaction from the tx map.
@@ -224,7 +224,7 @@ public:
         @return A pair of nullptr if the
                 key is not found in the tx map.
     */
-    virtual tx_type
+    [[nodiscard]] virtual tx_type
     txRead(key_type const& key) const = 0;
 
     //
@@ -257,7 +257,7 @@ public:
 
         @return std::nullopt if the item does not exist.
     */
-    virtual std::optional<digest_type>
+    [[nodiscard]] virtual std::optional<digest_type>
     digest(key_type const& key) const = 0;
 };
 

include/xrpl/ledger/detail/ApplyStateTable.h

@@ -54,19 +54,19 @@ public:
         bool isDryRun,
         beast::Journal j);
 
-    bool
+    [[nodiscard]] bool
     exists(ReadView const& base, Keylet const& k) const;
 
-    std::optional<key_type>
+    [[nodiscard]] std::optional<key_type>
     succ(ReadView const& base, key_type const& key, std::optional<key_type> const& last) const;
 
-    std::shared_ptr<SLE const>
+    [[nodiscard]] std::shared_ptr<SLE const>
     read(ReadView const& base, Keylet const& k) const;
 
     std::shared_ptr<SLE>
     peek(ReadView const& base, Keylet const& k);
 
-    std::size_t
+    [[nodiscard]] std::size_t
     size() const;
 
     void
@@ -97,7 +97,7 @@ public:
     destroyXRP(XRPAmount const& fee);
 
     // For debugging
-    XRPAmount const&
+    [[nodiscard]] XRPAmount const&
     dropsDestroyed() const
     {
         return dropsDestroyed_;

include/xrpl/ledger/detail/ApplyViewBase.h

@@ -22,51 +22,51 @@ public:
     ApplyViewBase(ReadView const* base, ApplyFlags flags);
 
     // ReadView
-    bool
+    [[nodiscard]] bool
     open() const override;
 
-    LedgerHeader const&
+    [[nodiscard]] LedgerHeader const&
     header() const override;
 
-    Fees const&
+    [[nodiscard]] Fees const&
     fees() const override;
 
-    Rules const&
+    [[nodiscard]] Rules const&
     rules() const override;
 
-    bool
+    [[nodiscard]] bool
     exists(Keylet const& k) const override;
 
-    std::optional<key_type>
+    [[nodiscard]] std::optional<key_type>
     succ(key_type const& key, std::optional<key_type> const& last = std::nullopt) const override;
 
-    std::shared_ptr<SLE const>
+    [[nodiscard]] std::shared_ptr<SLE const>
     read(Keylet const& k) const override;
 
-    std::unique_ptr<sles_type::iter_base>
+    [[nodiscard]] std::unique_ptr<sles_type::iter_base>
     slesBegin() const override;
 
-    std::unique_ptr<sles_type::iter_base>
+    [[nodiscard]] std::unique_ptr<sles_type::iter_base>
     slesEnd() const override;
 
-    std::unique_ptr<sles_type::iter_base>
+    [[nodiscard]] std::unique_ptr<sles_type::iter_base>
     slesUpperBound(uint256 const& key) const override;
 
-    std::unique_ptr<txs_type::iter_base>
+    [[nodiscard]] std::unique_ptr<txs_type::iter_base>
     txsBegin() const override;
 
-    std::unique_ptr<txs_type::iter_base>
+    [[nodiscard]] std::unique_ptr<txs_type::iter_base>
     txsEnd() const override;
 
-    bool
+    [[nodiscard]] bool
     txExists(key_type const& key) const override;
 
-    tx_type
+    [[nodiscard]] tx_type
     txRead(key_type const& key) const override;
 
     // ApplyView
 
-    ApplyFlags
+    [[nodiscard]] ApplyFlags
     flags() const override;
 
     std::shared_ptr<SLE>

include/xrpl/ledger/detail/RawStateTable.h

@@ -42,10 +42,10 @@ public:
     void
     apply(RawView& to) const;
 
-    bool
+    [[nodiscard]] bool
     exists(ReadView const& base, Keylet const& k) const;
 
-    std::optional<key_type>
+    [[nodiscard]] std::optional<key_type>
     succ(ReadView const& base, key_type const& key, std::optional<key_type> const& last) const;
 
     void
@@ -57,19 +57,19 @@ public:
     void
     replace(std::shared_ptr<SLE> const& sle);
 
-    std::shared_ptr<SLE const>
+    [[nodiscard]] std::shared_ptr<SLE const>
     read(ReadView const& base, Keylet const& k) const;
 
     void
     destroyXRP(XRPAmount const& fee);
 
-    std::unique_ptr<ReadView::sles_type::iter_base>
+    [[nodiscard]] std::unique_ptr<ReadView::sles_type::iter_base>
     slesBegin(ReadView const& base) const;
 
-    std::unique_ptr<ReadView::sles_type::iter_base>
+    [[nodiscard]] std::unique_ptr<ReadView::sles_type::iter_base>
     slesEnd(ReadView const& base) const;
 
-    std::unique_ptr<ReadView::sles_type::iter_base>
+    [[nodiscard]] std::unique_ptr<ReadView::sles_type::iter_base>
     slesUpperBound(ReadView const& base, uint256 const& key) const;
 
 private:

include/xrpl/ledger/detail/ReadViewFwdRange.h

@@ -27,16 +27,16 @@ public:
 
     virtual ~ReadViewFwdIter() = default;
 
-    virtual std::unique_ptr<ReadViewFwdIter>
+    [[nodiscard]] virtual std::unique_ptr<ReadViewFwdIter>
     copy() const = 0;
 
-    virtual bool
+    [[nodiscard]] virtual bool
     equal(ReadViewFwdIter const& impl) const = 0;
 
     virtual void
     increment() = 0;
 
-    virtual value_type
+    [[nodiscard]] virtual value_type
     dereference() const = 0;
 };
 

include/xrpl/ledger/helpers/AMMHelpers.h

@@ -28,7 +28,7 @@ reduceOffer(auto const& amount)
     static Number const reducedOfferPct(9999, -4);
 
     // Make sure the result is always less than amount or zero.
-    NumberRoundModeGuard const mg(Number::towards_zero);
+    NumberRoundModeGuard const mg(Number::rounding_mode::towards_zero);
     return amount * reducedOfferPct;
 }
 
@@ -180,7 +180,7 @@ getAMMOfferStartWithTakerGets(
     if (targetQuality.rate() == beast::zero)
         return std::nullopt;
 
-    NumberRoundModeGuard const mg(Number::to_nearest);
+    NumberRoundModeGuard const mg(Number::rounding_mode::to_nearest);
     auto const f = feeMult(tfee);
     auto const a = 1;
     auto const b = pool.in * (1 - 1 / f) / targetQuality.rate() - 2 * pool.out;
@@ -202,7 +202,7 @@ getAMMOfferStartWithTakerGets(
         // Round downward to minimize the offer and to maximize the quality.
         // This has the most impact when takerGets is XRP.
         auto const takerGets =
-            toAmount<TOut>(getAsset(pool.out), nTakerGetsProposed, Number::downward);
+            toAmount<TOut>(getAsset(pool.out), nTakerGetsProposed, Number::rounding_mode::downward);
         return TAmounts<TIn, TOut>{swapAssetOut(pool, takerGets, tfee), takerGets};
     };
 
@@ -247,7 +247,7 @@ getAMMOfferStartWithTakerPays(
     if (targetQuality.rate() == beast::zero)
         return std::nullopt;
 
-    NumberRoundModeGuard const mg(Number::to_nearest);
+    NumberRoundModeGuard const mg(Number::rounding_mode::to_nearest);
     auto const f = feeMult(tfee);
     auto const& a = f;
     auto const b = pool.in * (1 + f);
@@ -269,7 +269,7 @@ getAMMOfferStartWithTakerPays(
         // Round downward to minimize the offer and to maximize the quality.
         // This has the most impact when takerPays is XRP.
         auto const takerPays =
-            toAmount<TIn>(getAsset(pool.in), nTakerPaysProposed, Number::downward);
+            toAmount<TIn>(getAsset(pool.in), nTakerPaysProposed, Number::rounding_mode::downward);
         return TAmounts<TIn, TOut>{takerPays, swapAssetIn(pool, takerPays, tfee)};
     };
 
@@ -341,7 +341,8 @@ changeSpotPriceQuality(
                                 << " " << to_string(pool.out) << " " << quality << " " << tfee;
                 return std::nullopt;
             }
-            auto const takerPays = toAmount<TIn>(getAsset(pool.in), nTakerPays, Number::upward);
+            auto const takerPays =
+                toAmount<TIn>(getAsset(pool.in), nTakerPays, Number::rounding_mode::upward);
             // should not fail
             if (auto amounts = TAmounts<TIn, TOut>{takerPays, swapAssetIn(pool, takerPays, tfee)};
                 Quality{amounts} < quality &&
@@ -447,32 +448,32 @@ swapAssetIn(TAmounts<TIn, TOut> const& pool, TIn const& assetIn, std::uint16_t t
         // fee
         saveNumberRoundMode const _{Number::getround()};
 
-        Number::setround(Number::upward);
+        Number::setround(Number::rounding_mode::upward);
         auto const numerator = pool.in * pool.out;
         auto const fee = getFee(tfee);
 
-        Number::setround(Number::downward);
+        Number::setround(Number::rounding_mode::downward);
         auto const denom = pool.in + assetIn * (1 - fee);
 
         if (denom.signum() <= 0)
             return toAmount<TOut>(getAsset(pool.out), 0);
 
-        Number::setround(Number::upward);
+        Number::setround(Number::rounding_mode::upward);
         auto const ratio = numerator / denom;
 
-        Number::setround(Number::downward);
+        Number::setround(Number::rounding_mode::downward);
         auto const swapOut = pool.out - ratio;
 
         if (swapOut.signum() < 0)
             return toAmount<TOut>(getAsset(pool.out), 0);
 
-        return toAmount<TOut>(getAsset(pool.out), swapOut, Number::downward);
+        return toAmount<TOut>(getAsset(pool.out), swapOut, Number::rounding_mode::downward);
     }
 
     return toAmount<TOut>(
         getAsset(pool.out),
         pool.out - (pool.in * pool.out) / (pool.in + assetIn * feeMult(tfee)),
-        Number::downward);
+        Number::rounding_mode::downward);
 }
 
 /** Swap assetOut out of the pool and swap in a proportional amount
@@ -509,36 +510,36 @@ swapAssetOut(TAmounts<TIn, TOut> const& pool, TOut const& assetOut, std::uint16_
 
         saveNumberRoundMode const _{Number::getround()};
 
-        Number::setround(Number::upward);
+        Number::setround(Number::rounding_mode::upward);
         auto const numerator = pool.in * pool.out;
 
-        Number::setround(Number::downward);
+        Number::setround(Number::rounding_mode::downward);
         auto const denom = pool.out - assetOut;
         if (denom.signum() <= 0)
         {
             return toMaxAmount<TIn>(getAsset(pool.in));
         }
 
-        Number::setround(Number::upward);
+        Number::setround(Number::rounding_mode::upward);
         auto const ratio = numerator / denom;
         auto const numerator2 = ratio - pool.in;
         auto const fee = getFee(tfee);
 
-        Number::setround(Number::downward);
+        Number::setround(Number::rounding_mode::downward);
         auto const feeMult = 1 - fee;
 
-        Number::setround(Number::upward);
+        Number::setround(Number::rounding_mode::upward);
         auto const swapIn = numerator2 / feeMult;
         if (swapIn.signum() < 0)
             return toAmount<TIn>(getAsset(pool.in), 0);
 
-        return toAmount<TIn>(getAsset(pool.in), swapIn, Number::upward);
+        return toAmount<TIn>(getAsset(pool.in), swapIn, Number::rounding_mode::upward);
     }
 
     return toAmount<TIn>(
         getAsset(pool.in),
         ((pool.in * pool.out) / (pool.out - assetOut) - pool.in) / feeMult(tfee),
-        Number::upward);
+        Number::rounding_mode::upward);
 }
 
 /** Return square of n.
@@ -597,7 +598,8 @@ getLPTokenRounding(IsDeposit isDeposit)
 {
     // Minimize on deposit, maximize on withdraw to ensure
     // AMM invariant sqrt(poolAsset1 * poolAsset2) >= LPTokensBalance
-    return isDeposit == IsDeposit::Yes ? Number::downward : Number::upward;
+    return isDeposit == IsDeposit::Yes ? Number::rounding_mode::downward
+                                       : Number::rounding_mode::upward;
 }
 
 inline Number::rounding_mode
@@ -605,7 +607,8 @@ getAssetRounding(IsDeposit isDeposit)
 {
     // Maximize on deposit, minimize on withdraw to ensure
     // AMM invariant sqrt(poolAsset1 * poolAsset2) >= LPTokensBalance
-    return isDeposit == IsDeposit::Yes ? Number::upward : Number::downward;
+    return isDeposit == IsDeposit::Yes ? Number::rounding_mode::upward
+                                       : Number::rounding_mode::downward;
 }
 
 }  // namespace detail

include/xrpl/ledger/helpers/LendingHelpers.h

@@ -1,15 +1,14 @@
 #pragma once
 
 #include <xrpl/ledger/View.h>
+#include <xrpl/protocol/Rules.h>
 #include <xrpl/protocol/st.h>
 
 namespace xrpl {
 
-struct PreflightContext;
-
 // Lending protocol has dependencies, so capture them here.
 bool
-checkLendingProtocolDependencies(PreflightContext const& ctx);
+checkLendingProtocolDependencies(Rules const& rules, STTx const& tx);
 
 static constexpr std::uint32_t secondsInYear = 365 * 24 * 60 * 60;
 
@@ -20,7 +19,7 @@ loanPeriodicRate(TenthBips32 interestRate, std::uint32_t paymentInterval);
 inline Number
 roundPeriodicPayment(Asset const& asset, Number const& periodicPayment, std::int32_t scale)
 {
-    return roundToAsset(asset, periodicPayment, scale, Number::upward);
+    return roundToAsset(asset, periodicPayment, scale, Number::rounding_mode::upward);
 }
 
 /* Represents the breakdown of amounts to be paid and changes applied to the
@@ -105,7 +104,7 @@ struct LoanState
     Number managementFeeDue;
 
     // Interest still due to be paid by the borrower.
-    Number
+    [[nodiscard]] Number
     interestOutstanding() const
     {
         XRPL_ASSERT_PARTS(
@@ -267,7 +266,7 @@ struct PaymentComponents
     //
     // @return The amount of tracked interest included in this payment that
     //         will be paid to the vault.
-    Number
+    [[nodiscard]] Number
     trackedInterestPart() const;
 };
 
@@ -341,7 +340,7 @@ struct LoanStateDeltas
     /* Calculates the total change across all components.
      * @return The sum of principal, interest, and management fee deltas.
      */
-    Number
+    [[nodiscard]] Number
     total() const
     {
         return principal + interest + managementFee;

include/xrpl/ledger/helpers/TokenHelpers.h

@@ -21,13 +21,13 @@ namespace xrpl {
 //------------------------------------------------------------------------------
 
 /** Controls the treatment of frozen account balances */
-enum FreezeHandling { fhIGNORE_FREEZE, fhZERO_IF_FROZEN };
+enum class FreezeHandling { fhIGNORE_FREEZE, fhZERO_IF_FROZEN };
 
 /** Controls the treatment of unauthorized MPT balances */
-enum AuthHandling { ahIGNORE_AUTH, ahZERO_IF_UNAUTHORIZED };
+enum class AuthHandling { ahIGNORE_AUTH, ahZERO_IF_UNAUTHORIZED };
 
 /** Controls whether to include the account's full spendable balance */
-enum SpendableHandling { shSIMPLE_BALANCE, shFULL_BALANCE };
+enum class SpendableHandling { shSIMPLE_BALANCE, shFULL_BALANCE };
 
 enum class WaiveTransferFee : bool { No = false, Yes };
 
@@ -135,7 +135,7 @@ accountHolds(
     AccountID const& issuer,
     FreezeHandling zeroIfFrozen,
     beast::Journal j,
-    SpendableHandling includeFullBalance = shSIMPLE_BALANCE);
+    SpendableHandling includeFullBalance = SpendableHandling::shSIMPLE_BALANCE);
 
 [[nodiscard]] STAmount
 accountHolds(
@@ -144,7 +144,7 @@ accountHolds(
     Issue const& issue,
     FreezeHandling zeroIfFrozen,
     beast::Journal j,
-    SpendableHandling includeFullBalance = shSIMPLE_BALANCE);
+    SpendableHandling includeFullBalance = SpendableHandling::shSIMPLE_BALANCE);
 
 [[nodiscard]] STAmount
 accountHolds(
@@ -154,7 +154,7 @@ accountHolds(
     FreezeHandling zeroIfFrozen,
     AuthHandling zeroIfUnauthorized,
     beast::Journal j,
-    SpendableHandling includeFullBalance = shSIMPLE_BALANCE);
+    SpendableHandling includeFullBalance = SpendableHandling::shSIMPLE_BALANCE);
 
 [[nodiscard]] STAmount
 accountHolds(
@@ -164,7 +164,7 @@ accountHolds(
     FreezeHandling zeroIfFrozen,
     AuthHandling zeroIfUnauthorized,
     beast::Journal j,
-    SpendableHandling includeFullBalance = shSIMPLE_BALANCE);
+    SpendableHandling includeFullBalance = SpendableHandling::shSIMPLE_BALANCE);
 
 // Returns the amount an account can spend of the currency type saDefault, or
 // returns saDefault if this account is the issuer of the currency in

include/xrpl/net/AutoSocket.h

@@ -43,7 +43,7 @@ public:
     {
     }
 
-    bool
+    [[nodiscard]] bool
     isSecure() const
     {
         return mSecure;

include/xrpl/net/HTTPClientSSLContext.h

@@ -58,7 +58,7 @@ public:
         return ssl_context_;
     }
 
-    bool
+    [[nodiscard]] bool
     sslVerify() const
     {
         return verify_;

include/xrpl/nodestore/Backend.h

@@ -34,7 +34,7 @@ public:
 
     /** Get the block size for backends that support it
      */
-    virtual std::optional<std::size_t>
+    [[nodiscard]] virtual std::optional<std::size_t>
     getBlockSize() const
     {
         return std::nullopt;
@@ -135,7 +135,7 @@ public:
     }
 
     /** Returns the number of file descriptors the backend expects to need. */
-    virtual int
+    [[nodiscard]] virtual int
     fdRequired() const = 0;
 };
 

include/xrpl/nodestore/Factory.h

@@ -16,7 +16,7 @@ public:
     virtual ~Factory() = default;
 
     /** Retrieve the name of this factory. */
-    virtual std::string
+    [[nodiscard]] virtual std::string
     getName() const = 0;
 
     /** Create an instance of this factory's backend.

include/xrpl/nodestore/NodeObject.h

@@ -9,7 +9,7 @@
 namespace xrpl {
 
 /** The types of node objects. */
-enum NodeObjectType : std::uint32_t {
+enum class NodeObjectType : std::uint32_t {
     hotUNKNOWN = 0,
     hotLEDGER = 1,
     hotACCOUNT_NODE = 3,
@@ -59,15 +59,15 @@ public:
     createObject(NodeObjectType type, Blob&& data, uint256 const& hash);
 
     /** Returns the type of this object. */
-    NodeObjectType
+    [[nodiscard]] NodeObjectType
     getType() const;
 
     /** Returns the hash of the data. */
-    uint256 const&
+    [[nodiscard]] uint256 const&
     getHash() const;
 
     /** Returns the underlying data. */
-    Blob const&
+    [[nodiscard]] Blob const&
     getData() const;
 
 private:

include/xrpl/nodestore/Types.h

@@ -6,6 +6,8 @@
 
 namespace xrpl::NodeStore {
 
+// Need to be named before converting
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum {
     // This is only used to pre-allocate the array for
     // batch objects and does not affect the amount written.
@@ -20,7 +22,7 @@ enum {
 };
 
 /** Return codes from Backend operations. */
-enum Status {
+enum class Status {
     ok = 0,
     notFound = 1,
     dataCorrupt = 2,

include/xrpl/nodestore/detail/DecodedBlob.h

@@ -21,7 +21,7 @@ public:
     DecodedBlob(void const* key, void const* value, int valueBytes);
 
     /** Determine if the decoding was successful. */
-    bool
+    [[nodiscard]] bool
     wasOk() const noexcept
     {
         return m_success;

include/xrpl/nodestore/detail/codec.h

@@ -127,7 +127,7 @@ nodeobject_decompress(void const* in, std::size_t in_size, BufferFactory&& bf)
             ostream os(out, result.second);
             write<std::uint32_t>(os, 0);
             write<std::uint32_t>(os, 0);
-            write<std::uint8_t>(os, hotUNKNOWN);
+            write<std::uint8_t>(os, static_cast<std::uint8_t>(NodeObjectType::hotUNKNOWN));
             write<std::uint32_t>(os, static_cast<std::uint32_t>(HashPrefix::innerNode));
             if (mask == 0)
                 Throw<std::runtime_error>("nodeobject codec v1: empty inner node");
@@ -173,7 +173,7 @@ nodeobject_decompress(void const* in, std::size_t in_size, BufferFactory&& bf)
             ostream os(out, result.second);
             write<std::uint32_t>(os, 0);
             write<std::uint32_t>(os, 0);
-            write<std::uint8_t>(os, hotUNKNOWN);
+            write<std::uint8_t>(os, static_cast<std::uint8_t>(NodeObjectType::hotUNKNOWN));
             write<std::uint32_t>(os, static_cast<std::uint32_t>(HashPrefix::innerNode));
             write(os, is(512), 512);
             break;
@@ -307,7 +307,7 @@ filter_inner(void* in, std::size_t in_size)
             ostream os(in, 9);
             write<std::uint32_t>(os, 0);
             write<std::uint32_t>(os, 0);
-            write<std::uint8_t>(os, hotUNKNOWN);
+            write<std::uint8_t>(os, static_cast<std::uint8_t>(NodeObjectType::hotUNKNOWN));
         }
     }
 }

include/xrpl/nodestore/detail/varint.h

@@ -54,8 +54,9 @@ read_varint(void const* buf, std::size_t buflen, std::size_t& t)
         return 1;
     }
     auto const used = n;
-    while (n--)
+    while (n > 0)
     {
+        --n;
         auto const d = p[n];
         auto const t0 = t;
         t *= 127;

include/xrpl/protocol/Asset.h

@@ -68,7 +68,7 @@ public:
     {
     }
 
-    AccountID const&
+    [[nodiscard]] AccountID const&
     getIssuer() const;
 
     template <ValidIssueType TIss>
@@ -80,16 +80,16 @@ public:
     get();
 
     template <ValidIssueType TIss>
-    constexpr bool
+    [[nodiscard]] constexpr bool
     holds() const;
 
-    std::string
+    [[nodiscard]] std::string
     getText() const;
 
-    constexpr value_type const&
+    [[nodiscard]] constexpr value_type const&
     value() const;
 
-    constexpr token_type
+    [[nodiscard]] constexpr token_type
     token() const;
 
     void
@@ -98,7 +98,7 @@ public:
     STAmount
     operator()(Number const&) const;
 
-    constexpr AmtType
+    [[nodiscard]] constexpr AmtType
     getAmountType() const;
 
     // Custom, generic visit implementation
@@ -111,7 +111,7 @@ public:
         return detail::visit(issue_, std::forward<Visitors>(visitors)...);
     }
 
-    constexpr bool
+    [[nodiscard]] constexpr bool
     native() const
     {
         return visit(
@@ -119,7 +119,7 @@ public:
             [&](MPTIssue const&) { return false; });
     }
 
-    bool
+    [[nodiscard]] bool
     integral() const
     {
         return visit(
@@ -169,7 +169,7 @@ Asset::holds() const
 }
 
 template <ValidIssueType TIss>
-constexpr TIss const&
+[[nodiscard]] constexpr TIss const&
 Asset::get() const
 {
     if (!std::holds_alternative<TIss>(issue_))

include/xrpl/protocol/ErrorCodes.h

@@ -17,6 +17,8 @@ namespace xrpl {
 //
 // Please only append to this table. Do not "fill-in" gaps and do not re-use
 // or repurpose error code values.
+// Protocol-wide, 50+ files
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum error_code_i {
     // -1 represents codes not listed in this enumeration
     rpcUNKNOWN = -1,
@@ -148,6 +150,8 @@ enum error_code_i {
 
     These values need to remain stable.
 */
+// Protocol-wide, 50+ files
+// NOLINTNEXTLINE(cppcoreguidelines-use-enum-class)
 enum warning_code_i {
     warnRPC_UNSUPPORTED_MAJORITY = 1001,
     warnRPC_AMENDMENT_BLOCKED = 1002,

include/xrpl/protocol/Fees.h

@@ -39,7 +39,7 @@ struct Fees
         The reserve is calculated as the reserve base plus
         the reserve increment times the number of increments.
     */
-    XRPAmount
+    [[nodiscard]] XRPAmount
     accountReserve(std::size_t ownerCount) const
     {
         return reserve + ownerCount * increment;

include/xrpl/protocol/IOUAmount.h

@@ -71,13 +71,13 @@ public:
     operator bool() const noexcept;
 
     /** Return the sign of the amount */
-    int
+    [[nodiscard]] int
     signum() const noexcept;
 
-    exponent_type
+    [[nodiscard]] exponent_type
     exponent() const noexcept;
 
-    mantissa_type
+    [[nodiscard]] mantissa_type
     mantissa() const noexcept;
 
     static IOUAmount

include/xrpl/protocol/InnerObjectFormats.h

@@ -18,7 +18,7 @@ public:
     static InnerObjectFormats const&
     getInstance();
 
-    SOTemplate const*
+    [[nodiscard]] SOTemplate const*
     findSOTemplateBySField(SField const& sField) const;
 };