Description

JelleZijlstra

opened on May 8, 2026

Issue body actions

Bug report

Bug description:

Compare:

>>> type(defaultdict(int) | frozendict())
<class 'dict'>
>>> type(OrderedDict() | frozendict())
<class 'collections.OrderedDict'>
>>> type(defaultdict(int) | dict())
<class 'collections.defaultdict'>

This should be fixable by making defaultdict's nb_or use PyAnyDict_Check instead of PyDict_Check.

CPython versions tested on:

3.15

Operating systems tested on:

No response

Linked PRs

• gh-149534: Fix unification of defaultdict and frozendict with | #149539
• [3.15] gh-149534: Fix unification of defaultdict and frozendict with | (GH-149539) #150709

Activity

1. JelleZijlstra

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   3.15bugs and security fixesbugs and security fixes

   on May 8, 2026
2. StanFromIreland

   added

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   on May 9, 2026
3. StanFromIreland

   changed the title [-]defaultdict | frozendict returns dict, not defaultdict[/-] [+]`defaultdict | frozendict` returns `dict`, not `defaultdict`[/+] on May 9, 2026
4. sobolevn

   added 2 commits that reference this issue on Jun 1, 2026

   gh-149534: Fix unification of `defaultdict` and `frozendict` with `|` (…

   cc02693

   [3.15] gh-149534: Fix unification of `defaultdict` and `frozendict` w…

   3a12e9f
5. sobolevn

   closed this as completedon Jun 1, 2026

Issue actions