[giulio-leone]

Summary

Fixes #5188 — three linked bugs in the legacy A2A executor finalization path.

Root cause

The finalization logic in _handle_request (lines 276-318) only emitted state=completed when the aggregated message had non-empty .parts. Otherwise it fell through to an else-branch that echoed the raw aggregator state (working) into the final=True event.

Meanwhile, TaskResultAggregator replaced the accumulated message on every working event instead of concatenating text, and the synthesized Artifact never copied message.metadata.

Symptoms fixed

#	Symptom	Fix
1	Metadata-only / no-parts responses finalize as final=True, state=working	Else-branch resolves working → completed
2	Delta-streamed text only retains last chunk	_accumulate_message() concatenates TextPart.text and merges metadata
3	Synthesized artifact drops response metadata	Artifact now carries message.metadata

Files changed

File	Change
src/google/adk/a2a/executor/a2a_agent_executor.py	Terminal-state resolution + artifact metadata propagation
src/google/adk/a2a/executor/task_result_aggregator.py	Text accumulation + metadata merging via _accumulate_message()
tests/unittests/a2a/executor/test_a2a_agent_executor.py	3 new regression tests + 5 existing test expectations corrected
tests/unittests/a2a/executor/test_task_result_aggregator.py	3 new regression tests for delta accumulation + metadata merge

Tests

43 tests pass (37 existing + 6 new):

• test_metadata_only_response_completes — metadata-only → completed
• test_streamed_text_accumulated_in_final_artifact — concatenated text in artifact
• test_metadata_propagated_to_synthesized_artifact — message metadata → artifact
• test_delta_text_accumulation — aggregator concatenates TextPart chunks
• test_metadata_merged_across_working_events — aggregator merges metadata dicts
• test_accumulation_with_none_message_is_noop — None message doesn't clear state

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[rohityan]

Hi @giulio-leone , Thank you for your contribution! We appreciate you taking the time to submit this pull request. Please fix formatting errors by running autoformat.sh and mypy-diff tests.

[rohityan]

Hi @giulio-leone , Since the requested changes are still pending, I'm going to close this PR. Feel free to reopen once you've had a chance to address the requested changes, or create a new PR. Thanks!