SyntaxWarning: 'return' in a 'finally' block (Python 3.14)

Inizia in datadog_lambda/wrapper.py, all’interno di _LambdaDecorator.call, e analizza il flusso di controllo try/except/finally, in particolare il return segnalato alla riga 203. Verifica i quattro percorsi di esecuzione descritti nell’issue e aggiungi o aggiorna i test in modo che l’importazione con Python 3.14 non emetta alcun SyntaxWarning, mantenendo corrette le risposte bloccanti e normali.

Expected Behavior

No warnings emitted during Lambda cold start when importing datadog_lambda.

Actual Behavior

A SyntaxWarning is emitted at module import time (cold start) on Python 3.14:

/var/task/datadog_lambda/wrapper.py:203: SyntaxWarning: 'return' in a 'finally' block
  return self.blocking_response

This warning fires every cold start and pollutes CloudWatch logs. Python 3.14 introduced SyntaxWarning for return/break/continue inside finally blocks because such a return silently suppresses any exception that was actively propagating through the try/except.

Steps to Reproduce the Problem

1. Deploy a Lambda function using datadog-lambda on the Python 3.14 runtime
2. Trigger a cold start (first invocation or new sandbox)
3. Observe the SyntaxWarning in CloudWatch logs during INIT_START

Specifications

• Datadog Lambda Library version: 8.123.0
• Python version: 3.14

Root Cause

In _LambdaDecorator.__call__, the finally block contains a return:

finally:
    self._after(event, context)
    if self.blocking_response:
        return self.blocking_response  # ← triggers SyntaxWarning in Python 3.14

Proposed Fix

Remove return self.response from the try block and return self.blocking_response from the finally block, deferring both to after the entire try/except/finally:

    try:
        if self.blocking_response:
            return self.blocking_response
        self.response = self.func(event, context, **kwargs)
    except BlockingException:
        self.blocking_response = get_asm_blocked_response(self.event_source)
    except Exception:
        ...
        raise
    finally:
        self._after(event, context)

    if self.blocking_response:
        return self.blocking_response
    return self.response

All four execution paths (block before, block during, block after, normal) remain correct. Happy to open a PR with this fix and updated tests.

Stacktrace

/var/task/datadog_lambda/wrapper.py:203: SyntaxWarning: 'return' in a 'finally' block
return self.blocking_response