fix: remove return from finally block to resolve Python 3.14 SyntaxWa…#767
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fix: remove return from finally block to resolve Python 3.14 SyntaxWa…#767
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…rning Python 3.14 raises a SyntaxWarning for inside a block. Move the blocking_response return to after the try/except/finally in _LambdaDecorator.__call__, preserving all AppSec blocking execution paths. Add a regression test confirming handler exceptions still propagate when AppSec is enabled and no blocking response is active.
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purple4reina
approved these changes
Apr 1, 2026
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What does this PR do?
This is a community PR #759
Removes return self.blocking_response from the finally block in _LambdaDecorator.call and defers it to after the try/except/finally block, eliminating the SyntaxWarning: 'return' in a 'finally' block emitted by Python 3.14 at cold start.
Motivation
Python 3.14 introduced a SyntaxWarning for return/break/continue inside finally blocks because a return in finally silently suppresses any exception actively propagating through the try/except. This warning was firing on every Lambda cold start and polluting CloudWatch logs for anyone running on the Python 3.14 runtime.
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