GeezerVison is showing github.com — PEP 810 lazy from imports ignore module `__getattr__` when reifying · Issue #144957 · python/cpython
PEP 810 lazy from imports ignore module __getattr__ when reifying #144957Labels deferred-blockerinterpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)topic-lazy-importstype-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error DescriptionBug report
Bug description:
Without lazy imports:
python -c "from typing import Match; print(Match)"
With lazy imports:
python -c "lazy from typing import Match; print(Match)"
Traceback (most recent call last):
File "<string>", line 1, in <module>
lazy from typing import Match; print(Match)
ImportError: deferred import of 'typing.Match' raised an exception during resolution
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "<string>", line 1, in <module>
lazy from typing import Match; print(Match)
^^^^^
ImportError: cannot import name 'Match' from 'typing' (.../src/cpython/Lib/typing.py)
I believe the underlying issue is that the lazy import statement creates a lazy_import object in the module __dict__ which then prevents the module __getattr__ from being called. This occurs even if the module has already been imported.
demo_module.py
def __getattr__(name):
return namedemo_script.py
import demo_module
lazy from demo_module import ohno
try:
print(ohno)
except ImportError:
print("Import failed")
# The lazy from import has placed the ohno object in demo_module's globals
try:
print(demo_module.ohno)
except ImportError:
print("Failed again")
print({k: v for k, v in demo_module.__dict__.items() if not k.startswith("_")})
demo_module.__dict__.pop("ohno", None)
print(demo_module.ohno)python demo_script.py
Import failed
Failed again
{'ohno': <lazy_import 'demo_module.ohno'>}
ohno
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Linked PRs
Activitychanged the title [-]PEP810 lazy from imports ignore module `__getattr__` when reifying[/-] [+]PEP 810 lazy from imports ignore module `__getattr__` when reifying[/+] on Mar 13, 2026DavidCEllis commented on Apr 2, 2026 ContributorAuthor More actions I'd like to note that despite what that closed, linked, AI generated PR claimed this does not in fact work on Main (as of this morning). akaIDIOT commented on Apr 8, 2026 I can confirm this is still broken on 3.15a8 (running on linuxmint 22.3, python3.15 and python3.15t installed from packages provided by the deadsnakes ppa, both "3.15.0~a8-1+noble1"). The demo module + script posted by OP show the exact same output.
I'm running into the same erroneous import in local testing with PYTHON_LAZY_IMPORTS=all, where rich references typing.Match from rich.markup, crashing in a similar way:
File ".../python3.15t/site-packages/rich/markup.py", line 43, in <module>
_ReStringMatch = Match[str] # regex match object
^^^^^
ImportError: cannot import name 'Match' from 'typing' (/usr/lib/python3.15/typing.py)
Without PYTHON_LAZY_IMPORTS set, there is no issue. DavidCEllis commented on Apr 8, 2026 ContributorAuthor More actions rich using typing.Match is also how I found this, although via testing on pip list.
JelleZijlstra commented on May 9, 2026 Added the blocker label as I don't think we should release 3.15 without fixing this.
MetadataMetadatadeferred-blockerinterpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)topic-lazy-importstype-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error DevelopmentNo branches or pull requestsIssue actions
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