gh-137191: Fix how type parameters are collected from `Protocol` and `Generic` bases with parameters #137281

sobolevn · 2025-07-31T13:45:41Z

While fixing this problem, I've also noticed that code like

class ExtraTypeVars(P1[S], Protocol[T, T2]): ...

never produced any TypeError, it is in contrast to

class ExtraTypeVars(P1[S], Generic[T, T2]): ...

which produced this error as it should. I've fixed this as well.

Issue: TypeError when omitting a Protocol type argument with default #137191

…` and `Generic` bases with parameters

Lib/typing.py

Misc/NEWS.d/next/Library/2025-07-31-16-43-16.gh-issue-137191.FIogE8.rst

sobolevn · 2025-07-31T15:22:41Z

Thank you! I will keep this open for a bit for any extra feedback :)

sobolevn · 2025-08-03T07:40:51Z

Looks like there are no objections / suggestions. Merging!

bedevere-bot · 2025-08-03T09:14:54Z

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM Raspbian Linux Asan 3.x (no tier) has failed when building commit 158b28d.

What do you need to do:

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Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1811/builds/69) and take a look at the build logs.
Check if the failure is related to this commit (158b28d) or if it is a false positive.
If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1811/builds/69

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

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remote: Enumerating objects: 14, done.        
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remote: Counting objects: 100% (13/13), done.        
remote: Compressing objects:  12% (1/8)        
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remote: Compressing objects: 100% (8/8), done.        
remote: Total 14 (delta 5), reused 5 (delta 5), pack-reused 1 (from 1)        
From https://github.com/python/cpython
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HEAD is now at 158b28dd190 gh-137191: Fix how type parameters are collected from `Protocol` and `Generic` bases with parameters (#137281)
Switched to and reset branch 'main'

configure: WARNING: no system libmpdec found; falling back to pure-Python version for the decimal module

In file included from ./Include/internal/pycore_dict.h:11,
                 from Objects/typeobject.c:7:
In function ‘Py_DECREF_MORTAL’,
    inlined from ‘PyStackRef_XCLOSE’ at ./Include/internal/pycore_stackref.h:730:9,
    inlined from ‘_PyThreadState_PopCStackRef’ at ./Include/internal/pycore_stackref.h:810:5,
    inlined from ‘vectorcall_maybe’ at Objects/typeobject.c:3107:9:
./Include/internal/pycore_object.h:481:8: warning: array subscript 0 is outside array bounds of ‘PyObject[0]’ {aka ‘struct _object[]’} [-Warray-bounds]
  481 |     if (--op->ob_refcnt == 0) {
      |        ^

Timeout (0:05:00)!
Thread 0x0000007f7ceef100 [Thread-2] (most recent call first):
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/subprocess.py", line 2044 in _wait
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/subprocess.py", line 1277 in wait
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 194 in _run_process
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 299 in run_tmp_files
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 363 in _runtest
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 403 in run
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/threading.py", line 1074 in _bootstrap_inner
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/threading.py", line 1036 in _bootstrap

Thread 0x0000007f7d6ff100 [Thread-1] (most recent call first):
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/subprocess.py", line 2057 in _wait
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/subprocess.py", line 1277 in wait
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 194 in _run_process
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 299 in run_tmp_files
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 363 in _runtest
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 403 in run
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/threading.py", line 1074 in _bootstrap_inner
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/threading.py", line 1036 in _bootstrap

Thread 0x0000007f893fa6c0 [python] (most recent call first):
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/utils.py", line 82 in format_duration
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 464 in get_running
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 551 in _get_result
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/run_workers.py", line 610 in run
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/main.py", line 455 in _run_tests_mp
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/main.py", line 561 in _run_tests
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/main.py", line 598 in run_tests
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/main.py", line 767 in main
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/libregrtest/main.py", line 775 in main
  File "/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/Lib/test/__main__.py", line 2 in <module>
  File "<frozen runpy>", line 88 in _run_code
  File "<frozen runpy>", line 198 in _run_module_as_main
make: *** [Makefile:2494: buildbottest] Error 1

Cannot open file '/home/buildbot/buildarea/3.x.pablogsal-rasp.asan/build/test-results.xml' for upload

pythongh-137191: Fix how type parameters are collected from `Protocol…

5291b13

…` and `Generic` bases with parameters

sobolevn requested review from JelleZijlstra and AlexWaygood as code owners July 31, 2025 13:45

bedevere-app bot added the awaiting core review label Jul 31, 2025

bedevere-app bot mentioned this pull request Jul 31, 2025

TypeError when omitting a Protocol type argument with default #137191

Closed

sobolevn added the 3.15 new features, bugs and security fixes label Jul 31, 2025

Fix lint

555199f

JelleZijlstra reviewed Jul 31, 2025

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JelleZijlstra reviewed Jul 31, 2025

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Misc/NEWS.d/next/Library/2025-07-31-16-43-16.gh-issue-137191.FIogE8.rst Show resolved Hide resolved

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JelleZijlstra approved these changes Jul 31, 2025

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bedevere-app bot added awaiting merge and removed awaiting core review labels Jul 31, 2025

sobolevn merged commit 158b28d into python:main Aug 3, 2025
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bedevere-app bot removed the awaiting merge label Aug 3, 2025

sobolevn mentioned this pull request Aug 3, 2025

ARM Raspbian Linux Asan 3.x buildbot failure: "warning: array subscript 0 is outside array bounds" #137336

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gh-137191: Fix how type parameters are collected from `Protocol` and `Generic` bases with parameters #137281

gh-137191: Fix how type parameters are collected from `Protocol` and `Generic` bases with parameters #137281

sobolevn commented Jul 31, 2025 •

edited by bedevere-app bot

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gh-137191: Fix how type parameters are collected from Protocol and Generic bases with parameters #137281

gh-137191: Fix how type parameters are collected from Protocol and Generic bases with parameters #137281

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⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

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gh-137191: Fix how type parameters are collected from `Protocol` and `Generic` bases with parameters #137281

gh-137191: Fix how type parameters are collected from `Protocol` and `Generic` bases with parameters #137281

sobolevn commented Jul 31, 2025 •

edited by bedevere-app bot

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