Fix how type parameters are collected from parametrized Protocol bases
#667
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| typevar_types = (TypeVar, typing.TypeVar, ParamSpec) | ||
| if hasattr(typing, "ParamSpec"): # Python 3.10+ | ||
| typevar_types += (typing.ParamSpec,) | ||
| tvars = _collect_type_vars(cls.__orig_bases__, typevar_types) |
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note: for compatibility with both 3.9 and 3.10+, c.f. python/cpython#26091
| args, | ||
| *, | ||
| enforce_default_ordering=_marker, | ||
| validate_all=False, |
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note: since typing only explicitly passes validate_all from inside _generic_init_subclass (which this monkey patches below), there's no need for sys._getframe hacks like what was done for enforce_default_ordering in #392.
| if enforce_default_ordering is _marker: | ||
| enforce_default_ordering = _has_generic_or_protocol_as_origin() |
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note: using a placeholder default value for enforce_default_ordering allows the same function to work as _collect_parameters on Python <3.13 and as _collect_type_parameters on Python 3.13+. Another alternative would be to split this into separate <3.13 and 3.13+ implementations in respective version branches
| def _collect_parameters( | ||
| args, | ||
| *, | ||
| enforce_default_ordering=_marker, | ||
| validate_all=False, | ||
| ): |
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I saw that there have been previous issues where monkey patching typing internals can break future versions of typing if new parameters are added (c.f. python/cpython#118900). I think there's low risk of that here, since this only monkey patches internal functions on Python <3.15, and it seems unlikely that new parameter would be backported to 3.14 at this point. But if we wanted to help guard against that, I suppose adding an ignored **kwargs parameter might be an option?
Fixes #636, backport of python/cpython#137281
Added some inline comments about the implementation below.