`ast.parse` with lower `feature_version` is still allowed to parse `lazy import os`
Open
@sobolevn is already working on this.
Since Jun 29, 2026.
interpreter-core
topic-lazy-imports
topic-parser
type-bug
- Dominant language
- Python
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- 77.2k
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Description
Bug report
Code:
>>> import ast
>>> ast.parse('lazy import os', feature_version=(3, 12))
Works and parses lazy import on older python versions :(
It should produce something like:
>>> import ast
>>> ast.parse('lazy import os', feature_version=(3, 12))
Traceback (most recent call last):
File "<python-input-1>", line 1, in <module>
ast.parse('lazy import os', feature_version=(3, 12))
~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/sobolev/Desktop/cpython/Lib/ast.py", line 46, in parse
return compile(source, filename, mode, flags,
_feature_version=feature_version, optimize=optimize,
module=module)
File "<unknown>", line 1
lazy import os
^
SyntaxError: Lazy imports are only supported in Python 3.15 and greater
I have a PR ready.
Linked PRs
- gh-152632
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