add checks in StackTrie to ensure lastKey() is safe to use

Signed-off-by: garyschulte <garyschulte@gmail.com>

Author: garyschulte

datatypes/src/main/java/org/hyperledger/besu/datatypes/Hash.java

@@ -29,6 +29,9 @@ public class Hash extends DelegatingBytes32 {
   /** The constant ZERO. */
   public static final Hash ZERO = new Hash(Bytes32.ZERO);
 
+  /** Last hash */
+  public static final Hash LAST = new Hash(Bytes32.fromHexString("F".repeat(64)));
+
   /**
    * Hash of an RLP encoded trie hash with no content, or
    * "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/snapsync/StackTrie.java

@@ -125,7 +125,7 @@ public void commit(final FlatDatabaseUpdater flatDatabaseUpdater, final NodeUpda
               Function.identity(),
               Function.identity(),
               startKeyHash,
-              keys.lastKey(),
+              keys.size() > 0 ? keys.lastKey() : Hash.LAST,
               true);
 
       final MerkleTrie<Bytes, Bytes> trie =

ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/snapsync/request/StorageRangeDataRequestTest.java

@@ -18,7 +18,6 @@
 
 @ExtendWith(MockitoExtension.class)
 public class StorageRangeDataRequestTest {
-  private static final Hash HASH_LAST = Hash.fromHexString("F".repeat(64));
 
   @Mock WorldStateStorage storage;
   WorldStateProofProvider worldstateProofProvider = new WorldStateProofProvider(storage);
@@ -28,7 +27,7 @@ public void assertEmptySlotsWithProofOfExclusionCompletes() {
 
     var storageRangeRequest =
         new StorageRangeDataRequest(
-            Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, HASH_LAST);
+            Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, Hash.LAST);
 
     var proofs = new ArrayDeque<Bytes>();
     proofs.add(0, Hash.EMPTY_TRIE_HASH);
@@ -44,7 +43,7 @@ public void assertEmptySlotsWithProofOfExclusionCompletes() {
   public void assertEmptySlotsWithInvalidProofCompletes() {
     var storageRangeRequest =
         new StorageRangeDataRequest(
-            Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, HASH_LAST);
+            Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, Hash.EMPTY_TRIE_HASH, Bytes32.ZERO, Hash.LAST);
 
     var proofs = new ArrayDeque<Bytes>();
     proofs.add(0, Hash.ZERO);

evm/src/test/java/org/hyperledger/besu/evm/operations/BlockHashOperationTest.java

@@ -38,8 +38,7 @@ class BlockHashOperationTest {
 
   @Test
   void shouldReturnZeroWhenArgIsBiggerThanALong() {
-    assertBlockHash(
-        Bytes32.fromHexString("F".repeat(64)), Bytes32.ZERO, 100, n -> Hash.EMPTY_LIST_HASH);
+    assertBlockHash(Hash.LAST, Bytes32.ZERO, 100, n -> Hash.EMPTY_LIST_HASH);
   }
 
   @Test