def _do_prepare()

in tools/incremental_test/specification.py [0:0]

• 33 lines of code
• 4 McCabe index (conditional complexity)

    def _do_prepare(self, environment: Environment) -> Iterator[Path]:
        # Grab a temporary directory as the local root
        temporary_directory = environment.checked_run(
            working_directory=Path("."), command="mktemp -d"
        ).stdout.strip()
        root = Path(temporary_directory)
        LOG.debug(f"Using temporary directory {temporary_directory} as local root")

        watched = False
        try:
            # Write all files under the local root.
            all_files = {
                ".watchmanconfig": "{}",
                # Note that --binary and --typeshed still needs to be set in pyre flags.
                ".pyre_configuration": '{ "source_directories": [ "." ] }',
                **self.files,
            }
            FileRepositoryUpdate(changes=all_files, removals=[]).update(
                environment, root
            )

            # Watchman uses the "error" field instead of return code to signal errors
            watchman_output = environment.checked_run(
                working_directory=root, command="watchman watch ."
            ).stdout
            if "error" in json.loads(watchman_output):
                raise RuntimeError(
                    f"`watchman watch` invocation failed with output:\n{watchman_output}"
                )
            watched = True
            yield root
        finally:
            # Clean up the files we've written.
            if watched:
                environment.checked_run(
                    working_directory=root, command="watchman watch-del ."
                )
            environment.checked_run(
                working_directory=Path("."), command=f"rm -rf {temporary_directory}"
            )