Editable install (with -C editable_mode=strict) ignores MANIFEST.in

[studyingegret]

setuptools version

80.9.0

Python version

3.13.2

OS

Windows 11

Additional environment information

pip 25.2

Description

Title says it.

Expected behavior

No quack.py in steps 3 & 4, step 5 fail with no attribute B

How to Reproduce

1. Unzip this codebase: test2.zip
2. python -m venv .venv
3. python -m build and check if quack.py is in the distribution tarball
4. pip install -e . -C editable_mode=strict and check if quack.py is in the editable directory (e.g. build/__editable__.example_package_my_username_here-0.0.1-py3-none-any/thepackage)
5. python -c "import thepackage; print(thepackage.B)"

Output

No quack.py in step 3, quack.py in step 4, step 5 prints "quack".

Also step 3 emits warning: no previously-included files found matching 'src\thepackage\quack.py' several times.

Step 3 output

* Creating isolated environment: venv+pip...
* Installing packages in isolated environment:
  - setuptools == 80.9.0
* Getting build dependencies for sdist...
running egg_info
writing src\example_package_MY_USERNAME_HERE.egg-info\PKG-INFO
writing dependency_links to src\example_package_MY_USERNAME_HERE.egg-info\dependency_links.txt
writing top-level names to src\example_package_MY_USERNAME_HERE.egg-info\top_level.txt
reading manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
reading manifest template 'MANIFEST.in'
writing manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
* Building sdist...
running sdist
running egg_info
writing src\example_package_MY_USERNAME_HERE.egg-info\PKG-INFO
writing dependency_links to src\example_package_MY_USERNAME_HERE.egg-info\dependency_links.txt
writing top-level names to src\example_package_MY_USERNAME_HERE.egg-info\top_level.txt  
reading manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
reading manifest template 'MANIFEST.in'
writing manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
warning: sdist: standard file not found: should have one of README, README.rst, README.txt, README.md

running check
creating example_package_my_username_here-0.0.1
creating example_package_my_username_here-0.0.1\src\example_package_MY_USERNAME_HERE.egg-info
creating example_package_my_username_here-0.0.1\src\thepackage
copying files to example_package_my_username_here-0.0.1...
copying MANIFEST.in -> example_package_my_username_here-0.0.1
copying pyproject.toml -> example_package_my_username_here-0.0.1
copying src\example_package_MY_USERNAME_HERE.egg-info\PKG-INFO -> example_package_my_username_here-0.0.1\src\example_package_MY_USERNAME_HERE.egg-info
copying src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt -> example_package_my_username_here-0.0.1\src\example_package_MY_USERNAME_HERE.egg-info
copying src\example_package_MY_USERNAME_HERE.egg-info\dependency_links.txt -> example_package_my_username_here-0.0.1\src\example_package_MY_USERNAME_HERE.egg-info
copying src\example_package_MY_USERNAME_HERE.egg-info\top_level.txt -> example_package_my_username_here-0.0.1\src\example_package_MY_USERNAME_HERE.egg-info
copying src\thepackage\__init__.py -> example_package_my_username_here-0.0.1\src\thepackage
copying src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt -> example_package_my_username_here-0.0.1\src\example_package_MY_USERNAME_HERE.egg-info
Writing example_package_my_username_here-0.0.1\setup.cfg
Creating tar archive
removing 'example_package_my_username_here-0.0.1' (and everything under it)
* Building wheel from sdist
* Creating isolated environment: venv+pip...
* Installing packages in isolated environment:
  - setuptools == 80.9.0
* Getting build dependencies for wheel...
running egg_info
writing src\example_package_MY_USERNAME_HERE.egg-info\PKG-INFO
writing dependency_links to src\example_package_MY_USERNAME_HERE.egg-info\dependency_links.txt
writing top-level names to src\example_package_MY_USERNAME_HERE.egg-info\top_level.txt  
reading manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
reading manifest template 'MANIFEST.in'
warning: no previously-included files found matching 'src\thepackage\quack.py'
writing manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
* Building wheel...
running bdist_wheel
running build
running build_py
creating build\lib\thepackage
copying src\thepackage\__init__.py -> build\lib\thepackage
running egg_info
writing src\example_package_MY_USERNAME_HERE.egg-info\PKG-INFO
writing dependency_links to src\example_package_MY_USERNAME_HERE.egg-info\dependency_links.txt
writing top-level names to src\example_package_MY_USERNAME_HERE.egg-info\top_level.txt  
reading manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
reading manifest template 'MANIFEST.in'
warning: no previously-included files found matching 'src\thepackage\quack.py'
writing manifest file 'src\example_package_MY_USERNAME_HERE.egg-info\SOURCES.txt'       
installing to build\bdist.win-amd64\wheel
running install
running install_lib
creating build\bdist.win-amd64\wheel
creating build\bdist.win-amd64\wheel\thepackage
copying build\lib\thepackage\__init__.py -> build\bdist.win-amd64\wheel\.\thepackage    
running install_egg_info
Copying src\example_package_MY_USERNAME_HERE.egg-info to build\bdist.win-amd64\wheel\.\example_package_MY_USERNAME_HERE-0.0.1-py3.13.egg-info
running install_scripts
creating build\bdist.win-amd64\wheel\example_package_my_username_here-0.0.1.dist-info\WHEEL
creating 'D:\study-coding\test2\dist\.tmp-47d_w7a6\example_package_my_username_here-0.0.1-py3-none-any.whl' and adding 'build\bdist.win-amd64\wheel' to it
adding 'thepackage/__init__.py'
adding 'example_package_my_username_here-0.0.1.dist-info/METADATA'
adding 'example_package_my_username_here-0.0.1.dist-info/WHEEL'
adding 'example_package_my_username_here-0.0.1.dist-info/top_level.txt'
adding 'example_package_my_username_here-0.0.1.dist-info/RECORD'
removing build\bdist.win-amd64\wheel
Successfully built example_package_my_username_here-0.0.1.tar.gz and example_package_my_username_here-0.0.1-py3-none-any.whl

Step 4 output

Obtaining file:///D:/study-coding/test2
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build editable ... done
  Preparing editable metadata (pyproject.toml) ... done
Building wheels for collected packages: example_package_MY_USERNAME_HERE
  Building editable for example_package_MY_USERNAME_HERE (pyproject.toml) ... done
  Created wheel for example_package_MY_USERNAME_HERE: filename=example_package_my_username_here-0.0.1-0.editable-py3-none-any.whl size=1507 sha256=46da0493f16ed4b6fd25c0348bec009314d3f1928a9a50bb86d5575d8c8fe4da
  Stored in directory: C:\Users\mme\AppData\Local\Temp\pip-ephem-wheel-cache-ob8dd6pr\wheels\1e\31\86\8fe6e9d6df713fe7d4aef76f207ed052b7841a57b5736c62be
Successfully built example_package_MY_USERNAME_HERE
Installing collected packages: example_package_MY_USERNAME_HERE
Successfully installed example_package_MY_USERNAME_HERE-0.0.1

[MikhailRyazanov]

warning: no previously-included files found matching 'src\thepackage\quack.py'

Could this be related to #5093 in terms of mixing forward and backward slashes in paths on Windows?

[studyingegret]

@saisharan0103 What does 8 evidence hits mean?

[goutamadwant]

@abravalheri I opened a pull request #5290 that makes strict editable installs filter Python module mappings through the generated source manifest. It includes a regression test based on the reported MANIFEST.in exclusion and normalizes paths before comparison so platform-specific separators are handled consistently. Let me know if this looks good. thanks!