Reload flat db strategy on clear (#5619)

* reload flat db strategy on clear

Signed-off-by: Karim TAAM <karim.t2am@gmail.com>

---------

Signed-off-by: Karim TAAM <karim.t2am@gmail.com>

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/bonsai/storage/BonsaiWorldStateKeyValueStorage.java

@@ -87,7 +87,7 @@ public class BonsaiWorldStateKeyValueStorage implements WorldStateStorage, AutoC
     this.trieLogStorage =
         provider.getStorageBySegmentIdentifier(KeyValueSegmentIdentifier.TRIE_LOG_STORAGE);
     this.metricsSystem = metricsSystem;
-    initFlatDbStrategy();
+    loadFlatDbStrategy();
   }
 
   public BonsaiWorldStateKeyValueStorage(
@@ -109,7 +109,7 @@ public class BonsaiWorldStateKeyValueStorage implements WorldStateStorage, AutoC
     this.metricsSystem = metricsSystem;
   }
 
-  public void initFlatDbStrategy() {
+  public void loadFlatDbStrategy() {
     this.flatDbMode =
         FlatDbMode.fromVersion(
             trieBranchStorage
@@ -275,14 +275,14 @@ public class BonsaiWorldStateKeyValueStorage implements WorldStateStorage, AutoC
     final KeyValueStorageTransaction transaction = trieBranchStorage.startTransaction();
     transaction.put(FLAT_DB_MODE, FlatDbMode.FULL.getVersion().toArrayUnsafe());
     transaction.commit();
-    initFlatDbStrategy(); // force reload of flat db reader strategy
+    loadFlatDbStrategy(); // force reload of flat db reader strategy
   }
 
   public void downgradeToPartialFlatDbMode() {
     final KeyValueStorageTransaction transaction = trieBranchStorage.startTransaction();
     transaction.put(FLAT_DB_MODE, FlatDbMode.PARTIAL.getVersion().toArrayUnsafe());
     transaction.commit();
-    initFlatDbStrategy(); // force reload of flat db reader strategy
+    loadFlatDbStrategy(); // force reload of flat db reader strategy
   }
 
   @Override
@@ -291,7 +291,7 @@ public class BonsaiWorldStateKeyValueStorage implements WorldStateStorage, AutoC
     getFlatDbReaderStrategy().clearAll(accountStorage, storageStorage, codeStorage);
     trieBranchStorage.clear();
     trieLogStorage.clear();
-    flatDbReaderStrategy = null; // force reload of flat db reader strategy
+    loadFlatDbStrategy(); // force reload of flat db reader strategy
   }
 
   @Override

ethereum/core/src/test/java/org/hyperledger/besu/ethereum/bonsai/BonsaiWorldStateKeyValueStorageTest.java

@@ -335,6 +335,24 @@ public class BonsaiWorldStateKeyValueStorageTest {
     storage.clearFlatDatabase();
   }
 
+  @Test
+  public void clear_reloadFlatDbStrategy() {
+    final BonsaiWorldStateKeyValueStorage storage = spy(emptyStorage());
+
+    // save world state root hash
+    final BonsaiWorldStateKeyValueStorage.BonsaiUpdater updater = storage.updater();
+    updater.putAccountInfoState(Hash.ZERO, Bytes32.random()).commit();
+
+    assertThat(storage.getAccount(Hash.ZERO)).isNotEmpty();
+
+    // clear
+    storage.clear();
+
+    assertThat(storage.getFlatDbReaderStrategy()).isNotNull();
+
+    assertThat(storage.getAccount(Hash.ZERO)).isEmpty();
+  }
+
   @Test
   public void reconcilesNonConflictingUpdaters() {
     final Hash accountHashA = Hash.hash(Address.fromHexString("0x1"));