1 files changed, 17 insertions, 3 deletions
diff --git a/src/index/base.cpp b/src/index/base.cpp
index 1ebe89ef7c..3eea09b17d 100644
--- a/src/index/base.cpp
+++ b/src/index/base.cpp
@@ -18,6 +18,9 @@
 #include <validation.h> // For g_chainman
 #include <warnings.h>
 
+#include <string>
+#include <utility>
+
 using node::ReadBlockFromDisk;
 
 constexpr uint8_t DB_BEST_BLOCK{'B'};
@@ -62,8 +65,8 @@ void BaseIndex::DB::WriteBestBlock(CDBBatch& batch, const CBlockLocator& locator
     batch.Write(DB_BEST_BLOCK, locator);
 }
 
-BaseIndex::BaseIndex(std::unique_ptr<interfaces::Chain> chain)
-    : m_chain{std::move(chain)} {}
+BaseIndex::BaseIndex(std::unique_ptr<interfaces::Chain> chain, std::string name)
+    : m_chain{std::move(chain)}, m_name{std::move(name)} {}
 
 BaseIndex::~BaseIndex()
 {
@@ -295,6 +298,10 @@ void BaseIndex::BlockConnected(const std::shared_ptr<const CBlock>& block, const
     }
     interfaces::BlockInfo block_info = kernel::MakeBlockInfo(pindex, block.get());
     if (CustomAppend(block_info)) {
+        // Setting the best block index is intentionally the last step of this
+        // function, so BlockUntilSyncedToCurrentChain callers waiting for the
+        // best block index to be updated can rely on the block being fully
+        // processed, and the index object being safe to delete.
         SetBestBlockIndex(pindex);
     } else {
         FatalError("%s: Failed to write block %s to index",
@@ -411,10 +418,17 @@ IndexSummary BaseIndex::GetSummary() const
 void BaseIndex::SetBestBlockIndex(const CBlockIndex* block) {
     assert(!node::fPruneMode || AllowPrune());
 
-    m_best_block_index = block;
     if (AllowPrune() && block) {
         node::PruneLockInfo prune_lock;
         prune_lock.height_first = block->nHeight;
         WITH_LOCK(::cs_main, m_chainstate->m_blockman.UpdatePruneLock(GetName(), prune_lock));
     }
+
+    // Intentionally set m_best_block_index as the last step in this function,
+    // after updating prune locks above, and after making any other references
+    // to *this, so the BlockUntilSyncedToCurrentChain function (which checks
+    // m_best_block_index as an optimization) can be used to wait for the last
+    // BlockConnected notification and safely assume that prune locks are
+    // updated and that the index object is safe to delete.
+    m_best_block_index = block;
 }