Swallowed return_value in record_subsegment(...)?

[nelz9999]

My Python may not be super strong, but in my reading of try: except: finally:, it seems that the return_value is being trashed in the LOG_ERROR case.

From https://github.com/aws/aws-xray-sdk-python/blob/master/aws_xray_sdk/core/recorder.py:

        return_value = None

        try:
            return_value = wrapped(*args, **kwargs)
            return return_value
        except Exception as e:
            exception = e
            stack = traceback.extract_stack(limit=self._max_trace_back)
            raise
        finally:
            # No-op if subsegment is `None` due to `LOG_ERROR`.
            if subsegment is None:
                return

Isn't that last return actually equivalent to return None?

[haotianw465]

You are absolutely right. It should be

        return_value = None

        try:
            return_value = wrapped(*args, **kwargs)
            return return_value
        except Exception as e:
            exception = e
            stack = traceback.extract_stack(limit=self._max_trace_back)
            raise
        finally:
            # No-op if subsegment is `None` due to `LOG_ERROR`.
            if subsegment is None:
                return return_value

We have a unit test cover this scenario but unfortunately that unit test fails to check the return value. See https://github.com/aws/aws-xray-sdk-python/blob/master/tests/ext/botocore/test_botocore.py#L107.

Feel free to submit a PR and I can merge it as soon as possible. But regardless we will make sure this will be fixed in the next release.