Fix UnboundLocalError in send_request when response not assigned #1718
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Fixes an intermittent UnboundLocalError that could occur in send_request() when anyio's fail_after context manager incorrectly suppresses exceptions due to a race condition (anyio#589). Changes: - Initialize response_or_error to None before the try block - Add _process_response static method with defensive None check - Handle EndOfStream and ClosedResourceError exceptions explicitly - Use try/except/else structure for cleaner control flow - Add unit tests for _process_response Closes #1717
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Fixes an intermittent
UnboundLocalErrorthat could occur insend_request()at the line checkingisinstance(response_or_error, JSONRPCError).Motivation and Context
We received a report of intermittent
UnboundLocalErrorexceptions insend_request():This can occur due to a race condition in anyio's
fail_aftercontext manager (anyio#589) where exceptions may be incorrectly suppressed, leaving theresponse_or_errorvariable unassigned while execution continues past the try/except block.The fix:
response_or_errortoNonebefore the try block_process_responsestatic method with a defensiveNonecheckEndOfStreamandClosedResourceErrorexceptions explicitlyHow Has This Been Tested?
_process_responsecovering all code pathsBreaking Changes
None. This is a defensive fix that handles edge cases more gracefully.
Types of changes
Checklist
Additional context
Closes #1717
The root cause is a race condition in anyio where
fail_after's cancel scope can incorrectly suppress exceptions when a timeout and successful completion happen simultaneously. While this was reportedly fixed in anyio 4.0 (PR #591), edge cases may remain. This fix adds defensive code to handle the scenario gracefully rather than crashing withUnboundLocalError.