From c573704aa36686447d470d005015c9314a196dc5 Mon Sep 17 00:00:00 2001
From: marta-lokhova <marta@stellar.org>
Date: Fri, 13 Sep 2024 17:34:37 -0700
Subject: [PATCH] Rotate ledger headers if needed in
 SearchableBucketListSnapshot::getLedgerHeader

---
 src/bucket/BucketListSnapshot.cpp | 8 ++++++++
 src/bucket/BucketListSnapshot.h   | 6 +-----
 src/ledger/LedgerManagerImpl.cpp  | 1 -
 src/ledger/LedgerStateSnapshot.h  | 4 ++++
 4 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/bucket/BucketListSnapshot.cpp b/src/bucket/BucketListSnapshot.cpp
index e5adfb56bb..5d26fd8296 100644
--- a/src/bucket/BucketListSnapshot.cpp
+++ b/src/bucket/BucketListSnapshot.cpp
@@ -127,6 +127,14 @@ SearchableBucketListSnapshot::getLedgerSeq() const
     return mSnapshot->getLedgerSeq();
 }
 
+LedgerHeader const&
+SearchableBucketListSnapshot::getLedgerHeader()
+{
+    releaseAssert(mSnapshot);
+    mSnapshotManager.maybeUpdateSnapshot(mSnapshot, mHistoricalSnapshots);
+    return mSnapshot->getLedgerHeader();
+}
+
 EvictionResult
 SearchableBucketListSnapshot::scanForEviction(
     uint32_t ledgerSeq, EvictionCounters& counters,
diff --git a/src/bucket/BucketListSnapshot.h b/src/bucket/BucketListSnapshot.h
index 9b6fd5dcf8..ea14869f3a 100644
--- a/src/bucket/BucketListSnapshot.h
+++ b/src/bucket/BucketListSnapshot.h
@@ -102,10 +102,6 @@ class SearchableBucketListSnapshot : public NonMovableOrCopyable
                                    std::shared_ptr<EvictionStatistics> stats,
                                    StateArchivalSettings const& sas);
     uint32_t getLedgerSeq() const;
-    LedgerHeader const&
-    getLedgerHeader() const
-    {
-        return mSnapshot->getLedgerHeader();
-    }
+    LedgerHeader const& getLedgerHeader();
 };
 }
\ No newline at end of file
diff --git a/src/ledger/LedgerManagerImpl.cpp b/src/ledger/LedgerManagerImpl.cpp
index a5a7f33d88..2b7f328671 100644
--- a/src/ledger/LedgerManagerImpl.cpp
+++ b/src/ledger/LedgerManagerImpl.cpp
@@ -5,7 +5,6 @@
 #include "ledger/LedgerManagerImpl.h"
 #include "bucket/BucketList.h"
 #include "bucket/BucketManager.h"
-#include "bucket/test/BucketTestUtils.h"
 #include "catchup/AssumeStateWork.h"
 #include "crypto/Hex.h"
 #include "crypto/KeyUtils.h"
diff --git a/src/ledger/LedgerStateSnapshot.h b/src/ledger/LedgerStateSnapshot.h
index d60e5eb1ae..7a57b1c771 100644
--- a/src/ledger/LedgerStateSnapshot.h
+++ b/src/ledger/LedgerStateSnapshot.h
@@ -130,6 +130,10 @@ class BucketSnapshotState : public AbstractLedgerStateSnapshot
 // A helper class to create and query read-only snapshots
 // Automatically decides whether to create a BucketList (recommended), or SQL
 // snapshot (deprecated, but currently supported)
+// NOTE: LedgerSnapshot is meant to be short-lived, and should not be persisted
+// across _different_ ledgers, as the state under the hood might change. Users
+// are expected to construct a new LedgerSnapshot each time they want to query
+// ledger state.
 class LedgerSnapshot : public NonMovableOrCopyable
 {
     std::unique_ptr<AbstractLedgerStateSnapshot const> mGetter;