Update default values for ast.ImportFrom initialization

[hunterhogan]

(.313) C:\clones\typeshed>py
Python 3.13.5 (tags/v3.13.5:6cb20a2, Jun 11 2025, 16:15:46) [MSC v.1943 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> yum = ast.ImportFrom('popeyes', [ast.alias('chicken')])
>>> ast.unparse(yum)
'from popeyes import chicken'
>>> print(yum.level)
None

[hunterhogan]

Reverse chronological

3.15

(.venv) C:\clones\cpython>pcbuild\amd64\python_d
Python 3.15.0a0 (heads/main:28c71ee4b2e, Jun 17 2025, 22:00:57) [MSC v.1944 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> ast.ImportFrom()
ImportFrom(module=None, names=[], level=None)
>>> 

3.14, not installed or compiled

3.13 (also, see above)

Default values

(.313) C:\clones\typeshed>py
Python 3.13.5 (tags/v3.13.5:6cb20a2, Jun 11 2025, 16:15:46) [MSC v.1943 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> turkey = ast.ImportFrom()
>>> print(f"{turkey.module = }, {turkey.names = }, {turkey.level = }")
turkey.module = None, turkey.names = [], turkey.level = None
>>> ast.unparse(turkey)
'from  import '
>>> 

overload still necessary

(.313) C:\clones\typeshed>py
Python 3.13.5 (tags/v3.13.5:6cb20a2, Jun 11 2025, 16:15:46) [MSC v.1943 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> deepEnd = ast.ImportFrom([ast.alias('thePool')])                                                                                                                   
>>> print(f"{deepEnd.module = }, {deepEnd.names = }, {deepEnd.level = }")
deepEnd.module = [<ast.alias object at 0x000001E3BDF2F310>], deepEnd.names = [], deepEnd.level = None
>>> deepEnd = ast.ImportFrom(None, [ast.alias('thePool')])
>>> print(f"{deepEnd.module = }, {deepEnd.names = }, {deepEnd.level = }")
deepEnd.module = None, deepEnd.names = [<ast.alias object at 0x000001E3BDF60090>], deepEnd.level = None

3.12

keyword usage

>>> import ast
>>> silky = ast.ImportFrom()
>>> print(f"{silky.module = }, {silky.names = }, {silky.level = }")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'ImportFrom' object has no attribute 'names'
>>> silky = ast.ImportFrom(names=[ast.alias('punto', 'period')])
>>> print(f"{silky.module = }, {silky.names = }, {silky.level = }")
silky.module = None, silky.names = [<ast.alias object at 0x000001EB300D9050>], silky.level = None
>>> ast.unparse(silky)
'from  import punto as period'
>>>

Note that I copy-pasted 'from import punto as period' and there are two spaces without a . between "from" and "import". Not related to typing, but maybe it's an issue.

no keyword, no happy

>>> tired = ast.ImportFrom([ast.alias('stomachache')])
>>> print(f"{tired.module = }, {tired.names = }, {tired.level = }")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'ImportFrom' object has no attribute 'names'
>>> tired.module
[<ast.alias object at 0x000001EB3023AF90>]
>>> print(f"{tired.level = }")                                     
tired.level = None
>>> tired = ast.ImportFrom(None, [ast.alias('stomachache')])
>>> print(f"{tired.module = }, {tired.names = }, {tired.level = }")
tired.module = None, tired.names = [<ast.alias object at 0x000001EB3023AA10>], tired.level = None

3.11

(.311) C:\clones\typeshed>py
Python 3.11.9 (tags/v3.11.9:de54cf5, Apr  2 2024, 10:12:12) [MSC v.1938 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> blue = ast.ImportFrom(names=[ast.alias('moon')])
>>> print(f"{blue.module = }, {blue.names = }, {blue.level = }")
blue.module = None, blue.names = [<ast.alias object at 0x00000156222876D0>], blue.level = None
>>> ast.unparse(blue)
'from  import moon'
>>>

Also two spaces, no dot.

3.10

(.310) C:\clones\typeshed>py
Python 3.10.11 (tags/v3.10.11:7d4cc5a, Apr  5 2023, 00:38:17) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> quizas = ast.ImportFrom(names=[ast.alias('manana')])
>>> print(f"{quizas.module = }, {quizas.names = }, {quizas.level = }")
quizas.module = None, quizas.names = [<ast.alias object at 0x00000194028DE050>], quizas.level = None
>>> ast.unparse(quizas)
'from  import manana'
>>>

Ditto, no dotto.

3.9

(.309) C:\clones\typeshed>py
Python 3.9.13 (tags/v3.9.13:6de2ca5, May 17 2022, 16:36:42) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> play = ast.ImportFrom(names=[ast.alias('Mad_Libs')])
>>> print(f"{play.module = }, {play.names = }, {play.level = }")
play.module = None, play.names = [<ast.alias object at 0x000002590DBB7FD0>], play.level = None
>>> ast.unparse(play)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\hunte\AppData\Local\Programs\Python\Python39\lib\ast.py", line 1572, in unparse
    return unparser.visit(ast_obj)
  File "C:\Users\hunte\AppData\Local\Programs\Python\Python39\lib\ast.py", line 801, in visit
    self.traverse(node)
  File "C:\Users\hunte\AppData\Local\Programs\Python\Python39\lib\ast.py", line 795, in traverse
    super().visit(node)
  File "C:\Users\hunte\AppData\Local\Programs\Python\Python39\lib\ast.py", line 407, in visit
    return visitor(node)
  File "C:\Users\hunte\AppData\Local\Programs\Python\Python39\lib\ast.py", line 846, in visit_ImportFrom
    self.write("." * node.level)
TypeError: can't multiply sequence by non-int of type 'NoneType'
>>> import ast
>>> Europe = ast.ImportFrom(names=[ast.alias('zero', 'Arabic_numerals')], level = 0)
>>> print(f"{Europe.module = }, {Europe.names = }, {Europe.level = }")
Europe.module = None, Europe.names = [<ast.alias object at 0x000002590D88E4C0>], Europe.level = 0
>>> ast.unparse(Europe)
'from  import zero as Arabic_numerals'
>>>

So, level is required and cannot be None?

And the dot is still missing: from[space][space]import...

New commit, failing tests

I'll submit a new commit. I see failing tests above, but I haven't looked at them.

[hunterhogan]

Local test failures

On my local system, I ran

(.venv) C:\clones\typeshed>ver & py -V

Microsoft Windows [Version 10.0.26100.4351]
Python 3.12.10

(.venv) C:\clones\typeshed>tests\runtests.py stdlib/ast.pyi

...

Running stubtest...
c:\clones\typeshed\.venv\Scripts\python.exe -m mypy.stubtest --check-typeshed --show-traceback --custom-typeshed-dir . --allowlist stdlib\@tests\stubtest_allowlists\common.txt --allowlist stdlib\@tests\stubtest_allowlists\win32.txt --allowlist stdlib\@tests\stubtest_allowlists\py312.txt --allowlist stdlib\@tests\stubtest_allowlists\win32-py312.txt
note: unused allowlist entry _ast.ImportFrom.level
note: unused allowlist entry ast.ImportFrom.level
Found 2 errors (checked 732 modules)

That lead me to "stdlib@tests\stubtest_allowlists\common.txt" and the entries

_ast.ImportFrom.level  # None on the class, but never None on instances

argparse.Namespace.__setattr__  # should allow setting any attribute

ast.ImportFrom.level  # None on the class, but never None on instances

This aspect of the testing process was unknown to me before now. I don't know if or how I should address it.

GitHub actions test failures

I looked at the Window Py 3.13 test, and the GitHub test failures are the same as my local failure. ("... my local failure." That was a little too on-the-nose.)

Failure is good; war is peace.

Claude 4 in VS Code Copilot assured me that the test failures were a good thing.

The failing tests in Prefect are actually validating that your type improvements are working correctly. You might want to add a comment explaining that the mypy_primer failures are expected and beneficial - they're exposing existing type safety issues in downstream code.

Therefore, you're welcome.

I don't know what I should do next, if anything.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉