updated logic to make sure lockHint get propagated only for ReadWriteTransaction

Author: rahul2393

google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java

@@ -951,7 +951,7 @@ ResultSet readInternalWithOptions(
     } else if (defaultDirectedReadOptions != null) {
       builder.setDirectedReadOptions(defaultDirectedReadOptions);
     }
-    if (readOptions.hasLockHint()) {
+    if (readOptions.hasLockHint() && !isReadOnly()) {
       builder.setLockHint(readOptions.lockHint());
     }
     final int prefetchChunks =

google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java

@@ -1757,7 +1757,7 @@ public void testExecuteReadWithOrderByOption() {
   }
 
   @Test
-  public void testExecuteReadWithLockHintOption() {
+  public void testUnsupportedTransactionWithLockHintOption() {
     DatabaseClient client =
         spanner.getDatabaseClient(DatabaseId.of(TEST_PROJECT, TEST_INSTANCE, TEST_DATABASE));
     try (ResultSet resultSet =
@@ -1771,6 +1771,32 @@ public void testExecuteReadWithLockHintOption() {
       consumeResults(resultSet);
     }
 
+    List<ReadRequest> requests = mockSpanner.getRequestsOfType(ReadRequest.class);
+    assertThat(requests).hasSize(1);
+    ReadRequest request = requests.get(0);
+    // lock hint is only supported in  ReadWriteTransaction
+    assertEquals(LockHint.LOCK_HINT_UNSPECIFIED, request.getLockHint());
+  }
+
+  @Test
+  public void testReadWriteTransactionWithLockHint() {
+    DatabaseClient client =
+        spanner.getDatabaseClient(DatabaseId.of(TEST_PROJECT, TEST_INSTANCE, TEST_DATABASE));
+
+    TransactionRunner runner = client.readWriteTransaction();
+    runner.run(
+        transaction -> {
+          try (ResultSet resultSet =
+              transaction.read(
+                  READ_TABLE_NAME,
+                  KeySet.singleKey(Key.of(1L)),
+                  READ_COLUMN_NAMES,
+                  Options.lockHint(RpcLockHint.EXCLUSIVE))) {
+            consumeResults(resultSet);
+          }
+          return null;
+        });
+
     List<ReadRequest> requests = mockSpanner.getRequestsOfType(ReadRequest.class);
     assertThat(requests).hasSize(1);
     ReadRequest request = requests.get(0);

google-cloud-spanner/src/test/java/com/google/cloud/spanner/OptionsTest.java

@@ -409,9 +409,9 @@ public void testReadOptionsWithLockHintEquality() {
         Options.fromReadOptions(Options.lockHint(RpcLockHint.SHARED));
     assertEquals(optionsWithSharedLockHint1, optionsWithSharedLockHint2);
 
-    Options optionsWithExclusiveLockOrder =
+    Options optionsWithExclusiveLock =
         Options.fromReadOptions(Options.lockHint(RpcLockHint.EXCLUSIVE));
-    assertNotEquals(optionsWithSharedLockHint1, optionsWithExclusiveLockOrder);
+    assertNotEquals(optionsWithSharedLockHint1, optionsWithExclusiveLock);
   }
 
   @Test