from __future__ import annotations import ast import sys def main(): for path in sys.argv[1:] or sys.stdin.read().splitlines(): with open(path, 'rb') as path_fd: lines = path_fd.read().splitlines() missing = True if not lines: # Files are allowed to be empty of everything including boilerplate missing = False invalid_future = [] for text in lines: if text in (b'from __future__ import annotations', b'from __future__ import annotations # pragma: nocover'): missing = False break if text.strip().startswith(b'from __future__ ') or text.strip().startswith(b'__metaclass__ '): invalid_future.append(text.decode()) if missing: with open(path) as file: contents = file.read() # noinspection PyBroadException try: node = ast.parse(contents) # files consisting of only assignments have no need for future import boilerplate # the most likely case is that of a documentation only python file if all(isinstance(statement, ast.Assign) for statement in node.body): missing = False except Exception: # pylint: disable=broad-except pass # the compile sanity test will report this error if missing: print('%s: missing: from __future__ import annotations' % path) for text in invalid_future: print('%s: invalid: %s' % (path, text)) if __name__ == '__main__': main()