What is supposed to work under `-X lazy_imports=none`?

[ZeroIntensity]

After seeing #149318, I was curious as to what the effect would be when run with -X lazy_imports=none. To my surprise, I noticed that very little seems to work under the setting already.

For example, trying to run the test suite fails:

$ ./python -Xlazy_imports=none -m test
Exception ignored in the internal traceback machinery:
Traceback (most recent call last):
 File "/home/peter/develop/cpython/Lib/traceback.py", line 15, in <module>
 import tokenize
 File "/home/peter/develop/cpython/Lib/tokenize.py", line 38, in <module>
 lazy import _colorize
 File "/home/peter/develop/cpython/Lib/_colorize.py", line 6, in <module>
 from dataclasses import dataclass, field, Field
 File "/home/peter/develop/cpython/Lib/dataclasses.py", line 5, in <module>
 import annotationlib
 File "/home/peter/develop/cpython/Lib/annotationlib.py", line 3, in <module>
 import ast
 File "/home/peter/develop/cpython/Lib/ast.py", line 24, in <module>
 lazy from _colorize import can_colorize, get_theme
ImportError: cannot import name 'can_colorize' from partially initialized module '_colorize' (most likely due to a circular import) (/home/peter/develop/cpython/Lib/_colorize.py)
Traceback (most recent call last):
 File "/home/peter/develop/cpython/Lib/runpy.py", line 201, in _run_module_as_main
 return _run_code(code, main_globals, None,
 File "/home/peter/develop/cpython/Lib/runpy.py", line 87, in _run_code
 exec(code, run_globals)
 File "/home/peter/develop/cpython/Lib/test/__main__.py", line 1, in <module>
 from test.libregrtest.main import main
 File "/home/peter/develop/cpython/Lib/test/libregrtest/main.py", line 8, in <module>
 import trace
 File "/home/peter/develop/cpython/Lib/trace.py", line 56, in <module>
 import tokenize
 File "/home/peter/develop/cpython/Lib/tokenize.py", line 38, in <module>
 lazy import _colorize
 File "/home/peter/develop/cpython/Lib/_colorize.py", line 6, in <module>
 from dataclasses import dataclass, field, Field
 File "/home/peter/develop/cpython/Lib/dataclasses.py", line 5, in <module>
 import annotationlib
 File "/home/peter/develop/cpython/Lib/annotationlib.py", line 3, in <module>
 import ast
 File "/home/peter/develop/cpython/Lib/ast.py", line 24, in <module>
 lazy from _colorize import can_colorize, get_theme
ImportError: cannot import name 'can_colorize' from partially initialized module '_colorize' (most likely due to a circular import) (/home/peter/develop/cpython/Lib/_colorize.py)

The new REPL doesn't work:

$ ./python -X lazy_imports=none
Python 3.15.0a8+ (heads/pr_149318:6a88c2deeb3, May 3 2026, 10:35:20) [GCC 15.2.1 20260209] on linux
Type "help", "copyright", "credits" or "license" for more information.
Failed calling sys.__interactivehook__
Exception ignored in the internal traceback machinery:
Traceback (most recent call last):
 File "/home/peter/develop/cpython/Lib/traceback.py", line 15, in <module>
 import tokenize
 File "/home/peter/develop/cpython/Lib/tokenize.py", line 38, in <module>
 lazy import _colorize
 File "/home/peter/develop/cpython/Lib/_colorize.py", line 170, in <module>
 @dataclass(frozen=True, kw_only=True)
 File "/home/peter/develop/cpython/Lib/dataclasses.py", line 1456, in wrap
 return _process_class(cls, init, repr, eq, order, unsafe_hash,
 File "/home/peter/develop/cpython/Lib/dataclasses.py", line 1064, in _process_class
 cls_annotations = annotationlib.get_annotations(
AttributeError: module 'annotationlib' has no attribute 'get_annotations'
Traceback (most recent call last):
 File "/home/peter/develop/cpython/Lib/site.py", line 513, in register_readline
 import rlcompleter # noqa: F401
 File "/home/peter/develop/cpython/Lib/rlcompleter.py", line 34, in <module>
 import inspect
 File "/home/peter/develop/cpython/Lib/inspect.py", line 146, in <module>
 from annotationlib import Format, ForwardRef
 File "/home/peter/develop/cpython/Lib/annotationlib.py", line 3, in <module>
 import ast
 File "/home/peter/develop/cpython/Lib/ast.py", line 24, in <module>
 lazy from _colorize import can_colorize, get_theme
 File "/home/peter/develop/cpython/Lib/_colorize.py", line 170, in <module>
 @dataclass(frozen=True, kw_only=True)
 File "/home/peter/develop/cpython/Lib/dataclasses.py", line 1456, in wrap
 return _process_class(cls, init, repr, eq, order, unsafe_hash,
 File "/home/peter/develop/cpython/Lib/dataclasses.py", line 1064, in _process_class
 cls_annotations = annotationlib.get_annotations(
AttributeError: module 'annotationlib' has no attribute 'get_annotations'
warning: can't use pyrepl: module 'annotationlib' has no attribute 'get_annotations'
>>> 

I compiled a list of all the standard library modules that currently don't work under -X lazy_imports=none:

1. mailbox
2. logging
3. bdb
4. pdb
5. ast
6. tokenize
7. turtle
8. ensurepip
9. inspect
10. unittest
11. py_compile
12. tabnanny
13. code
14. asyncio
15. traceback
16. antigravity
17. contextlib
18. doctest
19. pathlib
20. pstats
21. compileall
22. zipfile
23. getpass
24. zipapp
25. pydoc
26. webbrowser
27. configparser
28. subprocess
29. venv
30. rlcompleter
31. pyclbr
32. difflib
33. trace
34. annotationlib
35. imaplib
36. pickletools
37. glob

I've already raised my concerns about this on DPO (in fact, LWN wrote an entire article about this), but anyway, what do we do? Do we consider this a bug? If so, how do we test for it? If not, then what is supposed to work? We should document the restrictions and expected behavior for disabling lazy imports.

Linked PRs

• gh-149321: Fix stdlib imports with lazy imports disabled #149338
• gh-149321: Remove lazy_imports=none startup mode #149389
• [3.15] gh-149321: Remove lazy_imports=none startup mode (GH-149389) #150129

[picnixz]

I consider it a bug for now because the stdlib is not working with our own new feature :') Whether it's intended to be documented, explained, or whatever, something is missing.

[hugovk]

Ping @pablogsal.

[pablogsal]

#149338 should take care of it and prevent it to happen again

[pablogsal]

CC @DinoV @Yhg1s

[pablogsal]

We still can decide to amend the PEP and remove the option if we think is that not being able to use it in the stdlib points out is broken enough.