gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format by mschoettle · Pull Request #145756 · python/cpython · GitHub

Uses annotation format FORWARDREF instead of the default VALUE when calling inspect.signature.
STRING also seems to work but affects existing tests that check the signature.

Issue: Autospeccing with unittest.mock is less robust with PEP 649 #145754

Closes #145754

…n format

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This change looks right to me, please add a unit test and we'll hopefully get it merged!

This change looks right to me, please add a unit test and we'll hopefully get it merged!

Thanks, @JelleZijlstra! I added a unit test. Are you able to review it or does it require @cjw296 as the code owner?

Sorry, looks like I never submitted this review.

I am comfortable merging this once I'm happy with the code.

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Thanks @mschoettle for the PR, and @JelleZijlstra for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

…orwardref annotation format (pythonGH-145756) (cherry picked from commit d357a7d) Co-authored-by: Matthias Schoettle <git@mattsch.com>

GH-146191 is a backport of this pull request to the 3.14 branch.

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot x86 Debian Non-Debug with X 3.x (no tier) has failed when building commit d357a7d.

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Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
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https://buildbot.python.org/#/builders/1245/builds/7793

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/contextlib.py"�[0m, line �[35m85�[0m, in �[35minner�[0m
    return func(*args, **kwds)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m597�[0m, in �[35mtest_interrupt�[0m
    exitcode = self._kill_process(multiprocessing.Process.interrupt)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/contextlib.py"�[0m, line �[35m85�[0m, in �[35minner�[0m
    return func(*args, **kwds)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m578�[0m, in �[35m_kill_process�[0m
    self.assertEqual(�[31mjoin�[0m�[1;31m()�[0m, None)
                     �[31m~~~~�[0m�[1;31m^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m251�[0m, in �[35m__call__�[0m
    return �[31mself.func�[0m�[1;31m(*args, **kwds)�[0m
           �[31m~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/multiprocessing/process.py"�[0m, line �[35m156�[0m, in �[35mjoin�[0m
    res = self._popen.wait(timeout)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/multiprocessing/popen_fork.py"�[0m, line �[35m44�[0m, in �[35mwait�[0m
    return �[31mself.poll�[0m�[1;31m(os.WNOHANG if timeout == 0.0 else 0)�[0m
           �[31m~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/multiprocessing/popen_fork.py"�[0m, line �[35m28�[0m, in �[35mpoll�[0m
    pid, sts = �[31mos.waitpid�[0m�[1;31m(self.pid, flag)�[0m
               �[31m~~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m574�[0m, in �[35mhandler�[0m
    raise RuntimeError('join took too long: %s' % p)
�[1;35mRuntimeError�[0m: �[35mjoin took too long: <Process name='Process-1' pid=12129 parent=12127 started daemon>�[0m


Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/contextlib.py"�[0m, line �[35m85�[0m, in �[35minner�[0m
    return func(*args, **kwds)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m597�[0m, in �[35mtest_interrupt�[0m
    exitcode = self._kill_process(multiprocessing.Process.interrupt)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/contextlib.py"�[0m, line �[35m85�[0m, in �[35minner�[0m
    return func(*args, **kwds)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m578�[0m, in �[35m_kill_process�[0m
    self.assertEqual(�[31mjoin�[0m�[1;31m()�[0m, None)
                     �[31m~~~~�[0m�[1;31m^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m251�[0m, in �[35m__call__�[0m
    return �[31mself.func�[0m�[1;31m(*args, **kwds)�[0m
           �[31m~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/multiprocessing/process.py"�[0m, line �[35m156�[0m, in �[35mjoin�[0m
    res = self._popen.wait(timeout)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/multiprocessing/popen_fork.py"�[0m, line �[35m44�[0m, in �[35mwait�[0m
    return �[31mself.poll�[0m�[1;31m(os.WNOHANG if timeout == 0.0 else 0)�[0m
           �[31m~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/multiprocessing/popen_fork.py"�[0m, line �[35m28�[0m, in �[35mpoll�[0m
    pid, sts = �[31mos.waitpid�[0m�[1;31m(self.pid, flag)�[0m
               �[31m~~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.nondebug/build/Lib/test/_test_multiprocessing.py"�[0m, line �[35m574�[0m, in �[35mhandler�[0m
    raise RuntimeError('join took too long: %s' % p)
�[1;35mRuntimeError�[0m: �[35mjoin took too long: <Process name='Process-158' pid=21989 parent=19679 started daemon>�[0m

…forwardref annotation format (GH-145756) (#146191) gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format (GH-145756) (cherry picked from commit d357a7d) Co-authored-by: Matthias Schoettle <git@mattsch.com>

* upstream/main: (1475 commits) Docs: replace all `datetime` imports with `import datetime as dt` (python#145640) pythongh-146153: Use `frozendict` in pure python fallback for `curses.has_key` (python#146154) pythongh-138234: clarify returncode behavior for subprocesses created with `shell=True` (python#138536) pythongh-140947: fix contextvars handling for server tasks in asyncio (python#141158) pythonGH-100108: Add async generators best practices section (python#141885) pythonGH-145667: Merge `GET_ITER` and `GET_YIELD_FROM_ITER` (pythonGH-146120) pythongh-146228: Better fork support in cached FastPath (python#146231) pythongh-146227: Fix wrong type in _Py_atomic_load_uint16 in pyatomic_std.h (pythongh-146229) pythongh-145980: Fix copy/paste mistake in binascii.c (python#146230) pythongh-146092: Raise MemoryError on allocation failure in _zoneinfo (python#146165) pythongh-91279: Note `SOURCE_DATE_EPOCH` support in `ZipFile.writestr()` doc (python#139396) pythongh-146196: Fix Undefined Behavior in _PyUnicodeWriter_WriteASCIIString() (python#146201) pythongh-143930: Reject leading dashes in webbrowser URLs pythongh-145916: Soft-deprecate ctypes.util.find_library (pythonGH-145919) pythongh-146205: Check the errno with != 0 in close impls in select module (python#146206) pythongh-146171: Fix nested AttributeError suggestions (python#146188) pythongh-146099: Optimize _GUARD_CODE_VERSION+IP via function version symbols (pythonGH-146101) pythongh-145980: Add support for alternative alphabets in the binascii module (pythonGH-145981) pythongh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format (python#145756) pythongh-145177: Add emscripten run --test, uses test args from config.toml (python#146160) ...

…orwardref annotation format (python#145756)

unittest.mock: Update signature retrieval to use String annotatio…

1342951

…n format

bedevere-app Bot mentioned this pull request Mar 10, 2026

Autospeccing with unittest.mock is less robust with PEP 649 #145754

Closed

blurb-it Bot and others added 2 commits March 10, 2026 14:57

📜🤖 Added by blurb_it.

d64ded3

use forwardref instead

ae68a42

mschoettle changed the title gh-145754: Update signature retrieval in unittest.mock to use string annotation format gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format Mar 10, 2026

fix backticks in news entry

71caad2

JelleZijlstra added the needs backport to 3.14 bugs and security fixes label Mar 10, 2026

add test

5d9a394

mschoettle marked this pull request as ready for review March 10, 2026 16:53

mschoettle requested a review from cjw296 as a code owner March 10, 2026 16:53

bedevere-app Bot added the awaiting review label Mar 10, 2026

epenet mentioned this pull request Mar 11, 2026

Remove 'from __future__ import annotations' home-assistant/core#165306

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emontnemery mentioned this pull request Mar 11, 2026

Remove 'from __future__ import annotations' in tests home-assistant/core#165301

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JelleZijlstra reviewed Mar 19, 2026

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Comment thread Lib/test/test_unittest/testmock/testmock.py Outdated

Comment thread Lib/test/test_unittest/testmock/testmock.py Outdated

Comment thread Misc/NEWS.d/next/Library/2026-03-10-14-57-15.gh-issue-145754.YBL5Ko.rst Outdated

mschoettle and others added 3 commits March 19, 2026 12:15

Apply suggestions from code review

569deb2

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Merge branch 'python:main' into patch-1

78ec3dd

clean up

a5989fd

mschoettle requested a review from JelleZijlstra March 19, 2026 17:33

JelleZijlstra merged commit d357a7d into python:main Mar 20, 2026
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bedevere-app Bot removed the awaiting review label Mar 20, 2026

bedevere-app Bot removed the needs backport to 3.14 bugs and security fixes label Mar 20, 2026

pablogsal mentioned this pull request Apr 4, 2026

gh-130273: Fix traceback color output with unicode characters #142529

Merged

ljfp pushed a commit to ljfp/cpython that referenced this pull request Apr 25, 2026

pythongh-145754 : Update signature retrieval in unittest.mock to use f…

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…orwardref annotation format (python#145756)

gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format by mschoettle · Pull Request #145756 · python/cpython · GitHub

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gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format#145756
JelleZijlstra merged 8 commits into
python:mainfrom
mschoettle:patch-1

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gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format by mschoettle · Pull Request #145756 · python/cpython · GitHub

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gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format - #145756

gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format#145756JelleZijlstra merged 8 commits intopython:mainpython/cpython:mainfrom mschoettle:patch-1mschoettle/cpython:patch-1Copy head branch name to clipboard

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gh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format#145756
JelleZijlstra merged 8 commits into
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mschoettle:patch-1

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