gh-73536: Add support for multi-signatures by serhiy-storchaka · Pull Request #117671 · python/cpython

serhiy-storchaka · 2024-04-09T09:55:51Z

Add inspect.MultiSignature which is a subclass of inspect.Signature.
Add inspect.signatures().
inspect.signature() can now return a multi-signature.
Support multi-signatures in pydoc.
Support multi-signatures in IDLE calltips.
Support multi-signatures in dataclasses docstrings.
Allow multiple @text_signature in Argument Clinic.
Add representable signatures for all builtin functions and methods of builtin classes except type() and super().

Issue: Add support for multiple signatures #73536

* Add inspect.MultiSignature which is a subclass of inspect.Signature. * Add inspect.signatures(). * inspect.signature() can now return a multi-signature. * Support multi-signatures in pydoc. * Support multi-signatures in IDLE calltips. * Support multi-signatures in dataclasses docstrings. * Allow multiple @text_signature in Argument Clinic. * Add representable signatures for all builtin functions and methods of builtin classes except type() and super().

Gouvernathor · 2024-04-10T23:31:07Z



+def _multisignature_get_partial(wrapped_sig, partial, extra_args=()):
+ last_exc = None


Unless the case of the list being empty is handled elsewhere, this could result in a raise None. Maybe that None should instead be something like Exception("Empty MultiSignature list") ?

It is checked in the constructor. I think even about removing this assignment, NameError is clearer indication if something goes wrong.

Gouvernathor · 2024-04-10T23:35:28Z

+ return True
+ if isinstance(other, MultiSignature):
+ return self._signatures == other._signatures
+ if len(self._signatures) == 1 and isinstance(other, Signature):


I think this should be
Suggested change
iflen(self._signatures) ==1andisinstance(other, Signature):
ifisinstance(other, Signature):
returnlen(self._signatures) ==1
and the addition to Signature's eq should be removed, above.

No, it is not correct, it would make a 1-element MultiSignature equal to any Signature.
You perhaps mistyped, I wrote more correct fix.

I did. That's good. (I would suggest removing the line about MultiSignature in Signature's eq as I believe it's dead code now, but up to you).

It is not dead. It is called in SignatureSubclass() == MultiSignature(). Although it is not covered by tests yet.

Gouvernathor · 2024-04-10T23:40:16Z

+
 def signature(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=False):
 """Get a signature object for the passed callable."""
 return Signature.from_callable(obj, follow_wrapped=follow_wrapped,


Given that the original Signature.from_callable is not changed and does the exact same call to _from_callable, that means both signature and Signature.from_callable may return a MultiSignature object, right ?
Strictly speaking this is not a violation of backwards compatibility as MultiSignature is a subclass of Signature, but I find it weird and it may break some strict-type behaviors. Is there a way to have those only return pure Signature objects, without breaking everything this update brings to the table ?

Yes, it is. The idea was that inspect.signature() will start to support previously not supported cases and return a MultiSignature which should be compatible with Signature. But now I am no longer sure. They are not so well compatible as I expected, and in most cases I needed to rewrite the code to explicitly handle MultiSignature. This is why I added inspect.signatures(). Now the code is in the intermediate state -- either MultiSignature will be made more compatible with Signature and inspect.signatures() may disappear, or they will became completely different things.

serhiy-storchaka · 2024-04-11T06:30:47Z



+def _multisignature_get_partial(wrapped_sig, partial, extra_args=()):
+ last_exc = None


It is checked in the constructor. I think even about removing this assignment, NameError is clearer indication if something goes wrong.

serhiy-storchaka · 2024-04-11T06:36:27Z

+ return True
+ if isinstance(other, MultiSignature):
+ return self._signatures == other._signatures
+ if len(self._signatures) == 1 and isinstance(other, Signature):


No, it is not correct, it would make a 1-element MultiSignature equal to any Signature.
You perhaps mistyped, I wrote more correct fix.

serhiy-storchaka · 2024-04-11T06:44:58Z

+
 def signature(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=False):
 """Get a signature object for the passed callable."""
 return Signature.from_callable(obj, follow_wrapped=follow_wrapped,


Yes, it is. The idea was that inspect.signature() will start to support previously not supported cases and return a MultiSignature which should be compatible with Signature. But now I am no longer sure. They are not so well compatible as I expected, and in most cases I needed to rewrite the code to explicitly handle MultiSignature. This is why I added inspect.signatures(). Now the code is in the intermediate state -- either MultiSignature will be made more compatible with Signature and inspect.signatures() may disappear, or they will became completely different things.

…nd sys modules.

skirpichev · 2024-10-29T02:47:14Z

@serhiy-storchaka, now this again has conflicts with the main. I did pr serhiy-storchaka#22 that address this, hope it helps.

Are you thinking about writing a PEP as Petr suggested?

skirpichev · 2025-02-24T09:07:23Z

@serhiy-storchaka, will you be ok if I continue this work in a separate pr? Or you disappointed in this approach?

Version-specific patches adapted from existing ones: - relocatable-python-config: same change as 3.x-0001 but adjusted for line offset in 3.13+ python-config.sh.in (shared between 3.13 and 3.14 since the file is identical) - remove-module-deps: removes ProjectDependencies from the python project in PCbuild/pcbuild.sln (separate patches for 3.13 and 3.14 due to different GUID sets) - _ctypes-ffi (3.13 only): converts static formattable[] array to dynamic initialization for shared libffi compatibility. Not needed for 3.14 where this was fixed upstream by restructuring cfield.c into a named struct (python/cpython#117671) The _msi-vcxproj patch is no longer needed since msilib was removed in 3.13 per PEP 594 (python/cpython#104911).

github-actions · 2026-04-16T00:26:34Z

This PR is stale because it has been open for 30 days with no activity.

bedevere-appBot mentioned this pull request Apr 9, 2024
Add support for multiple signatures #73536
Open

erlend-aasland reviewed Apr 10, 2024
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Comment threadObjects/memoryobject.c Outdated
Comment threadPython/bltinmodule.c Outdated

serhiy-storchaka added 2 commits April 10, 2024 16:27

Add tests and fix errors.
54db6d3

Fix signatures of hex() methods.
9bbde5f

Gouvernathor reviewed Apr 10, 2024
View reviewed changes

Refactor support of partial and partialmethod.
5c9ddb9

serhiy-storchaka commented Apr 11, 2024
View reviewed changes

serhiy-storchaka added 5 commits April 11, 2024 09:47

Update Lib/inspect.py
5e7ca6d

Remove old commented out code.
53bc04e

Add $module for builtin functions.
1a3536f

Tests signatures of methods. Fix more signatures in builtins, types a…
6ff7151
…nd sys modules.

Merge branch 'main' into wip-inspect-multi-signature
2ad265a

serhiy-storchaka mentioned this pull request Apr 11, 2024
Add more signatures for builtin functions and methods #117764
Closed

Merge branch 'main' into wip-inspect-multi-signature
57f3abf

serhiy-storchaka mentioned this pull request Jun 7, 2024
int.__round__(None) is not supported #120080
Closed

Merge branch 'main' into wip-inspect-multi-signature
2227748

skirpichev self-requested a review October 29, 2024 03:02

skirpichev mentioned this pull request Nov 6, 2024
gh-125897: Use positional-only parameter indicators for range()#125945
Merged

skirpichev removed their request for review February 26, 2025 02:47

AA-Turner mentioned this pull request Feb 27, 2025
gh-127647: Add typing.Reader and Writer protocols #127648
Merged

Dutcho mentioned this pull request Mar 12, 2025
Add inspect.signature support for more builtins #107161
Open

This was referenced Mar 31, 2025
gh-131885: Updates docs to make max and min iterable param positional only #131868
Merged
Update function signatures to use * and / as needed #131885
Open

Merge branch 'main' into wip-inspect-multi-signature
5df505a

merwok changed the title ~~gh-73536: Add support of multi-signatures~~gh-73536: Add support for multi-signaturesApr 8, 2025

serhiy-storchaka added 2 commits April 9, 2025 12:31

Merge branch 'main' into wip-inspect-multi-signature
087fd94

Add more tests.
452bb6f

serhiy-storchaka added 2 commits August 10, 2025 10:18

Merge branch 'main' into wip-inspect-multi-signature
5a70fb0

Add signatures for FrameLocalsProxyType methods.
5678904

github-actionsBot added the stale Stale PR or inactive for long period of time. label Apr 16, 2026



		def _multisignature_get_partial(wrapped_sig, partial, extra_args=()):
		last_exc = None

	iflen(self._signatures) ==1andisinstance(other, Signature):
	ifisinstance(other, Signature):
	returnlen(self._signatures) ==1

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skirpichev commented Oct 29, 2024

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skirpichev commented Feb 24, 2025

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serhiy-storchaka commented Apr 9, 2024•
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