Fix: Properly await cancelled tasks in voice result streaming cleanup

[gn00295120]

Summary

Fixes resource leak and error handling issue in VoiceStreamResult where tasks are cancelled but not properly awaited during cleanup, and CancelledError could mask real exceptions.

Problem

The _cleanup_tasks() method in VoiceStreamResult had two issues:

1. Resource leak: Only calling task.cancel() without awaiting could lead to:

   • Unhandled task exception warnings
   • Potential resource leaks from abandoned tasks
   • Improper cleanup of background tasks

2. Error masking: _check_errors() calling task.exception() on cancelled tasks would raise CancelledError, masking the real exception

Evidence

• Similar to fixed guardrail tasks cleanup (PR Fix: Properly await cancelled guardrail tasks during cleanup #1976)
• Similar to fixed voice STT cleanup (PR Fix: Properly await cancelled tasks in voice STT cleanup #1977)
• Similar to fixed websocket cleanup (PR fix: await cancelled websocket task to prevent resource leak #1955)
• Bug documented in .claude/bug-analysis/03-resource-leaks.md

Solution

1. Made _cleanup_tasks() async
2. Collect all real asyncio.Task objects that need to be awaited
3. Added await asyncio.gather() with return_exceptions=True to properly collect exceptions from cancelled tasks
4. Updated _check_errors() to check task.cancelled() before calling task.exception() to avoid CancelledError
5. Updated stream() async generator to await _cleanup_tasks()

Testing

• Linting passes
• No breaking changes to public API
• Follows same pattern as PR Fix: Properly await cancelled guardrail tasks during cleanup #1976, Fix: Properly await cancelled tasks in voice STT cleanup #1977, fix: await cancelled websocket task to prevent resource leak #1955

Files Changed

• src/agents/voice/result.py: Fix task cleanup and error checking

[Copilot]

Pull Request Overview

This PR fixes a resource leak in the VoiceStreamResult class by properly awaiting cancelled tasks during cleanup and preventing CancelledError from masking real exceptions.

Key Changes:

• Made _cleanup_tasks() async to properly await cancelled tasks using asyncio.gather() with return_exceptions=True
• Enhanced _check_errors() to check task.cancelled() before calling task.exception() to avoid CancelledError
• Updated the stream() method to await the now-async _cleanup_tasks()

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".