fix(a2a): set final=True for error TaskStatusUpdateEvent in event_converter

[kuishou68]

Closes #5388

Problem

In _create_error_status_event inside src/google/adk/a2a/converters/event_converter.py, the TaskStatusUpdateEvent for a failed task is incorrectly created with final=False:

return TaskStatusUpdateEvent(
    ...
    status=TaskStatus(state=TaskState.failed, ...),
    final=False,  # BUG: should be True
)

A failed state is terminal — no further events will follow, so final must be True. Consumers that check this flag will otherwise wait indefinitely or mishandle the error.

Fix

Change final=False → final=True in _create_error_status_event.

The equivalent code in from_adk_event.py already uses final=True correctly (line 154), so this change makes event_converter.py consistent.

Testing

Existing unit tests for error event conversion should be updated/added to assert final=True.

Signed-off-by: Cocoon-Break 54054995+kuishou68@users.noreply.github.com

[adk-bot]

Response from ADK Triaging Agent

Hello @kuishou68, thank you for your contribution!

Your PR description is very clear and it's great that you've included an associated issue and a testing plan.

As per our contribution guidelines, could you please also include a summary of the passed pytest results to verify the fix? This will help speed up the review process.

Thanks!

[rohityan]

Hi @kuishou68, Thank you for your contribution! We appreciate you taking the time to submit this pull request. Your PR has been received by the team and is currently under review. We will provide feedback as soon as we have an update to share.

[rohityan]

Hi @sasha-gitg , can you please review this.

[sasha-gitg]

Thanks for the fix! The change looks correct and aligns with from_adk_event.py.

However, unit tests are missing to verify this change, as noted in the PR description.

I've verified the fix locally by adding a test case in test_event_converter.py to assert final=True for failed tasks. All unit tests passed.

Please add unit tests to this PR to ensure regression prevention. Here is the test case I used for verification:

  def test_create_error_status_event(self):
    """Test creation of error status event sets final=True."""
    self.mock_event.error_code = "ERROR_001"
    self.mock_event.error_message = "Test error"

    task_id = "test-task-id"
    context_id = "test-context-id"

    with patch(
        "google.adk.a2a.converters.event_converter.datetime"
    ) as mock_datetime:
      mock_datetime.fromtimestamp.return_value.isoformat.return_value = (
          "2023-01-01T00:00:00"
      )

      result = _create_error_status_event(
          self.mock_event,
          self.mock_invocation_context,
          task_id,
          context_id,
      )

      assert isinstance(result, TaskStatusUpdateEvent)
      assert result.task_id == task_id
      assert result.context_id == context_id
      assert result.status.state == TaskState.failed
      assert result.final is True