From a2488820d5f82f699090487f4cfdb3108bd93d3e Mon Sep 17 00:00:00 2001
From: Alex Kremer <akremer@ripple.com>
Date: Tue, 1 Sep 2026 17:43:35 +0100
Subject: [PATCH] Assert on incorrect shortcut

---
 src/rpc/RPCHelpers.cpp             | 10 +++++--
 src/rpc/RPCHelpers.hpp             | 12 +++++----
 tests/unit/rpc/RPCHelpersTests.cpp | 43 +++++++++++++++++++++++++++++-
 3 files changed, 57 insertions(+), 8 deletions(-)

diff --git a/src/rpc/RPCHelpers.cpp b/src/rpc/RPCHelpers.cpp
index e3ccc9528..80227143d 100644
--- a/src/rpc/RPCHelpers.cpp
+++ b/src/rpc/RPCHelpers.cpp
@@ -569,8 +569,14 @@ getLedgerHeaderFromLedgerSpecifier(
         return *lgrInfo;
     }
 
-    // A shortcut means the latest validated ledger; see the declaration for why that holds
-    // for all three of them.
+    if (resolved.isShortcut()) {
+        auto const shortcut = std::get<spec::LedgerShortcut>(resolved.value);
+        ASSERT(
+            shortcut == spec::LedgerShortcut::Validated,
+            "current/closed ledgers must be forwarded before dispatch"
+        );
+    }
+
     auto const ledgerSequence = resolved.isSequence() ? std::get<uint32_t>(resolved.value) : maxSeq;
 
     // return without hitting the db
diff --git a/src/rpc/RPCHelpers.hpp b/src/rpc/RPCHelpers.hpp
index a9a77fa8f..823e45b1f 100644
--- a/src/rpc/RPCHelpers.hpp
+++ b/src/rpc/RPCHelpers.hpp
@@ -59,6 +59,7 @@
 #include <memory>
 #include <optional>
 #include <string>
+#include <string_view>
 #include <tuple>
 #include <utility>
 #include <vector>
@@ -308,11 +309,12 @@ getLedgerHeaderFromHashOrSeq(
  * Behaviour matches that overload: a hash or sequence beyond @p maxSeq, or one absent from
  * the backend, yields @c ledgerNotFound.
  *
- * All three shortcuts resolve to @p maxSeq. Clio only serves validated data, so
- * @c validated is the latest validated sequence by definition, and @c current / @c closed
- * never arrive here — @ref specifiesCurrentOrClosedLedger forwards those upstream before
- * dispatch. An unspecified ledger resolves via @c LedgerSpecifier::resolved(), which the
- * spec library fixes to @c validated for Clio.
+ * A @c validated shortcut resolves to @p maxSeq, which is what it means for a server that
+ * only serves validated data. An unspecified ledger resolves via
+ * @c LedgerSpecifier::resolved(), which the spec library fixes to @c validated for Clio.
+ *
+ * @c current and @c closed cannot reach here: @ref specifiesCurrentOrClosedLedger forwards
+ * those upstream before dispatch.
  *
  * @param backend The backend to use
  * @param yield The coroutine context
diff --git a/tests/unit/rpc/RPCHelpersTests.cpp b/tests/unit/rpc/RPCHelpersTests.cpp
index 48ca1b794..eb73aed08 100644
--- a/tests/unit/rpc/RPCHelpersTests.cpp
+++ b/tests/unit/rpc/RPCHelpersTests.cpp
@@ -7,6 +7,7 @@
 #include "util/AsioContextTestFixture.hpp"
 #include "util/LoggerFixtures.hpp"
 #include "util/MockAmendmentCenter.hpp"
+#include "util/MockAssert.hpp"
 #include "util/MockBackendTestFixture.hpp"
 #include "util/MockPrometheus.hpp"
 #include "util/NameGenerator.hpp"
@@ -2140,7 +2141,7 @@ TEST_F(RPCHelpersTest, LedgerHeaderFromSpecifierBySequenceBeyondMaxSeqSkipsBacke
     });
 }
 
-TEST_F(RPCHelpersTest, LedgerHeaderFromSpecifierShortcutUsesMaxSeq)
+TEST_F(RPCHelpersTest, LedgerHeaderFromSpecifierValidatedUsesMaxSeq)
 {
     EXPECT_CALL(*backend_, fetchLedgerBySequence(kSpecifierRangeMax, _))
         .WillOnce(Return(createLedgerHeader(kIndex1, kSpecifierRangeMax)));
@@ -2157,6 +2158,46 @@ TEST_F(RPCHelpersTest, LedgerHeaderFromSpecifierShortcutUsesMaxSeq)
     });
 }
 
+struct RPCHelpersAssertTest : RPCHelpersTest, common::util::WithMockAssert {};
+
+TEST_F(RPCHelpersAssertTest, LedgerHeaderFromSpecifierCurrentAsserts)
+{
+    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(0);
+
+    runSpawn([&, this](auto yield) {
+        EXPECT_CLIO_ASSERT_FAIL_WITH_MESSAGE(
+            {
+                [[maybe_unused]] auto const res = getLedgerHeaderFromLedgerSpecifier(
+                    *backend_,
+                    yield,
+                    spec::LedgerSpecifier{spec::LedgerShortcut::Current},
+                    kSpecifierRangeMax
+                );
+            },
+            "must be forwarded before dispatch"
+        );
+    });
+}
+
+TEST_F(RPCHelpersAssertTest, LedgerHeaderFromSpecifierClosedAsserts)
+{
+    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(0);
+
+    runSpawn([&, this](auto yield) {
+        EXPECT_CLIO_ASSERT_FAIL_WITH_MESSAGE(
+            {
+                [[maybe_unused]] auto const res = getLedgerHeaderFromLedgerSpecifier(
+                    *backend_,
+                    yield,
+                    spec::LedgerSpecifier{spec::LedgerShortcut::Closed},
+                    kSpecifierRangeMax
+                );
+            },
+            "must be forwarded before dispatch"
+        );
+    });
+}
+
 TEST_F(RPCHelpersTest, LedgerHeaderFromSpecifierUnspecifiedResolvesToMaxSeq)
 {
     // an unspecified ledger resolves via LedgerSpecifier::resolved(), which the spec library