fix(sdk):explicitly catch and ignore token reset errors

[jjeliga]

Summary

Explicitly catch and ignore token reset errors during async context cleanup in case of nested contexts and resetting during context switch.

Linked Issues

Closes #1876

Documentation

• No Docs Needed:

If this PR adds new feature or changes existing. Make sure documentation is adjusted accordingly. If the docs is not needed, please explain why.

[gemini-code-assist]

Summary of Changes

Hello @jjeliga, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the robustness of asynchronous resource management by gracefully handling a specific ValueError that can occur when resetting contextvar tokens. By catching and ignoring errors where a token was created in a different context, the change prevents unexpected failures in complex asynchronous flows, ensuring smoother operation during context cleanup.

Highlights

• Error Handling for Contextvar Resets: Implemented explicit error handling for contextvar.reset(token) calls. Specifically, a ValueError indicating that a token was created in a different context will now be caught and ignored.
• Nested Contexts and Context Switches: This change addresses issues that can arise during asynchronous context cleanup, particularly in scenarios involving nested contexts or when resetting occurs during a context switch, preventing potential crashes.
• New Import: The re module has been imported to facilitate regular expression matching for identifying specific ValueError messages.

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[gemini-code-assist]

Code Review

This pull request addresses an issue with contextvar.reset raising a ValueError in nested async contexts by catching the specific exception. The approach of inspecting the exception message is reasonable given the constraints of the contextvars API. I've suggested a small improvement to make the check more robust and readable by using string methods instead of a regular expression, which also removes the need for a new import.

[gemini-code-assist]

Relying on exception messages is fragile. To make this check more robust and readable, you can use the endswith string method. This avoids using a regular expression for a simple string check, is more performant, and is less likely to break if the beginning of the error message changes in future Python versions. This change also makes the import re at the top of the file unnecessary and it should be removed.

Suggested change

	except ValueError as e:
	if re.match(r"<Token var=.+ was created in a different Context", str(e)):
	# Ignore contextvar reset errors when the contextvar was created in a different Context
	pass
	else:
	raise
	except ValueError as e:
	# This error can happen in nested async contexts and can be safely ignored.
	if not str(e).endswith("was created in a different Context"):
	raise