fix: quick workaround for flat storage memtrie comparison (#12592)

Quick fix to allow state comparison between flat storage and memtries
only when the view over key value pairs is at the same height, for both
of them.

integration-tests/src/test_loop/tests/resharding_v3.rs

@@ -37,6 +37,7 @@ use near_primitives::test_utils::create_user_test_signer;
 use near_primitives::transaction::SignedTransaction;
 use near_primitives::trie_key::TrieKey;
 use near_primitives::views::FinalExecutionStatus;
+use near_store::flat::FlatStorageStatus;
 use std::cell::Cell;
 use std::u64;
 
@@ -661,11 +662,25 @@ fn assert_state_sanity(
             trie.lock_for_iter().iter().unwrap().collect::<Result<HashSet<_>, _>>().unwrap();
         assert_state_equal(&memtrie_state, &trie_state, shard_uid, "memtrie and trie");
 
-        let Some(flat_store_chunk_view) = client
-            .chain
-            .runtime_adapter
-            .get_flat_storage_manager()
-            .chunk_view(shard_uid, final_head.last_block_hash)
+        let flat_storage_manager = client.chain.runtime_adapter.get_flat_storage_manager();
+        // FlatStorageChunkView::iter_range() used below to retrieve all key-value pairs in Flat
+        // Storage only looks at the data committed into the DB. For this reasons comparing Flat
+        // Storage and Memtries makes sense only if we can retrieve a view at the same height from
+        // both.
+        if let FlatStorageStatus::Ready(status) =
+            flat_storage_manager.get_flat_storage_status(shard_uid)
+        {
+            if status.flat_head.hash != final_head.prev_block_hash {
+                tracing::warn!(target: "test", "skipping flat storage - memtrie state check");
+                continue;
+            } else {
+                tracing::debug!(target: "test", "checking flat storage - memtrie state");
+            }
+        } else {
+            continue;
+        };
+        let Some(flat_store_chunk_view) =
+            flat_storage_manager.chunk_view(shard_uid, final_head.last_block_hash)
         else {
             continue;
         };