fix: resolve StopIteration error in BigQuery emulator fixture
#99
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Fixes a RuntimeError caused by StopIteration being raised inside a generator function when Docker container ports cannot be found. Changes: - Move container.reload() to the start of retry loop to ensure fresh port bindings are available - Replace unsafe next() call with explicit dict.get() for exact-key port matching (e.g., "9050/tcp" instead of startswith pattern) - Add descriptive error message showing available ports when lookup fails - Use RuntimeError instead of allowing StopIteration to propagate This fix ensures all database services (including BigQuery emulator) can properly start their Docker containers and expose ports reliably. Resolves issue where BigQuery tests failed with: "RuntimeError: generator raised StopIteration"
cofin
changed the title
cofin
changed the title
StopIteration error in BigQuery emulator fixture
provinzkraut
reviewed
Oct 6, 2025
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Updated to make the protocol configurable instead of implicitly trying UDP. Added a
This way services that need UDP can explicitly opt-in via |
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Summary
Fixes a
RuntimeError: generator raised StopIterationthat prevented the BigQuery emulator fixture from starting Docker containers. This issue affected BigQuery tests and could potentially impact other database services under certain conditions.Root Cause
The error occurred in
_service.py:188wherenext()was used without a default value inside a@contextmanagergenerator function:When no matching port key was found,
next()raisedStopIteration. Since Python 3.7+,StopIterationinside a generator is converted toRuntimeError, causing the cryptic error message.Changes
1. Enhanced retry loop (lines 178-182)
container.reload()called after checking portscontainer.reload()called before checking ports2. Safe port lookup with exact-key matching (lines 187-196)
next()withstartswith()pattern matchingdict.get()with exact protocol keys ("9050/tcp","9050/udp")StopIterationexceptionsRuntimeErrorfor consistency with fixture setup failures