Replace typing overloads with a functools.wraps declaration.

[jaraco]

No description provided.

[jaraco]

@bswck in #224 (comment) noted that this technique does in fact appear to do the right thing when types are validated with pylance, but not so much with mypy. That's actually pretty encouraging and suggests that may be the best approach for a library like this - to signal the intent and let the typing systems catch up. Especially if mypy is tracking this issue and has plans to implement it, I'd say that's good enough....

[jaraco]

python/mypy#10574 appears to be related. python/mypy#12573 suggests that mypy may be philosophically opposed to dynamic behavior.

[bswck]

I ended up with the silliest

open = open

being a working solution in both mypy and pylance.
The cutest part about it is that it also reduces the current wrapper implementation to a single assignment.
The doc is however copied entirely from builtins.open then, BUT the typing advantage is priceless.

[jaraco]

The doc is however copied entirely from builtins.open then

I suspect (and confirmed) that's also the case for functools.wraps(open), as that's part of what wraps does. The __doc__ could probably be retained by passing more parameters to functools.wraps (namely, passing the defaults minus __doc__), but that's unlikely to be elegant.

[bswck]

The doc is however copied entirely from builtins.open then

I suspect (and confirmed) that's also the case for functools.wraps(open), as that's part of what wraps does. The __doc__ could probably be retained by passing more parameters to functools.wraps (namely, passing the defaults minus __doc__), but that's unlikely to be elegant.

Yeah, it can be retained by assigned=tuple(set(functools.WRAPPER_ASSIGNMENTS) - {"__doc__"}) as I think about it rn.

[bswck]

It would be more useful for functools.wraps() to receive a parameter with attributes to skip. I'll try to suggest that in the Python community.

[jaraco]

It would be more useful for functools.wraps() to receive a parameter with attributes to skip. I'll try to suggest that in the Python community.

I wonder, though, if in this case, assigned=() would be the right thing to do.

[jaraco]

I've not used pylance. I have VSCode and I see Pylance warnings, but I'm unsure how to elicit the output of reveal_type.

[bswck]

It would be more useful for functools.wraps() to receive a parameter with attributes to skip. I'll try to suggest that in the Python community.

I wonder, though, if in this case, assigned=() would be the right thing to do.

Definitely this or ('__annotations__',), but I think the latter might be pretty enigmatic for others.

[bswck]

It would be more useful for functools.wraps() to receive a parameter with attributes to skip. I'll try to suggest that in the Python community.

I wonder, though, if in this case, assigned=() would be the right thing to do.

Definitely this or ('__annotations__',), but I think the latter might be pretty enigmatic for others.

Actually, nevermind. open/io.open doesn't have __annotations__ as it's a built-in with no runtime-bound type annotations, so that's a terrible idea 🤦‍♂️

[jaraco]

I should have been more cautious about merging this. It breaks on Python 3.11 (only, not 3.10 or 3.12) during test collection:

________________________________________________________ ERROR collecting path/__init__.py ________________________________________________________
/opt/homebrew/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/doctest.py:942: in find
    self._find(tests, obj, name, module, source_lines, globs, {})
/opt/homebrew/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/doctest.py:1016: in _find
    self._find(tests, val, valname, module, source_lines,
/opt/homebrew/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/doctest.py:1048: in _find
    self._find(tests, val, valname, module, source_lines,
/opt/homebrew/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/doctest.py:1004: in _find
    test = self._get_test(obj, name, module, globs, source_lines)
/opt/homebrew/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/doctest.py:1072: in _get_test
    lineno = self._find_lineno(obj, source_lines)
/opt/homebrew/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/doctest.py:1121: in _find_lineno
    obj = inspect.unwrap(obj).__code__
E   AttributeError: 'builtin_function_or_method' object has no attribute '__code__'

The issue was reported in python/cpython#117692.