Ofey Chan <ofey...@gmail.com> added the comment:
I fix the problem. But sorry for my last message, because it totally miss the point ;) In `inspect.signature()`, the order of handle `follow_wrapper_chains` and `functools.partial` cause the problem. Relevant code: https://github.com/python/cpython/blob/288af845a32fd2a92e3b49738faf8f2de6a7bf7c/Lib/inspect.py#L2408 The original order is: 1. `follow_wrapper_chains` unwrap decorators. - It would check `__wrapped__` attribute in `unwrap()`. - `functools.update_wrapper()` would set `__wrapped__`. 2. Then handle `functools.partial`, construct new signature with `_signature_get_partial()` So the original `functools.partial` object would skip (1), goto (2) and would be correctly processed. But after calling `functools.update_wrapper()`, the `functools.partial` object has a `__wrapped__` attribute, so it directly handled by (1) and will never reach (2). That's why `inspect.signature()` return the original function's signature. `update_wrapper.breaks.partial.signature.check.__wrapped__.py` shows the `__wrapped__` attribute. My solution is simple: swap the order of (1) and (2). `functools.partial` is a special type of wrapper, handle it before going down the wrapper chain is sane. And I have written test case to ensure it's correct, hope it works. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue46761> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
