Build includes an old file that had been removed from the souce code

[aendie]

My environment:
Operating System: Windows 10 Pro, Version 20H2, OS Build 19042.964
Python version: 3.9.4
Build installed via: python -m pip install --upgrade build
Build version: 0.3.1.post1
Published PyPI containing the build error: https://pypi.org/project/pyalmanac/1.2/

Problem description:
I recently noticed an incorrect build - the build included a file that I had deleted from the sources.

In my app/pyalmanac/lib folder I had 8 files, however one was a older copy that was not needed:

• alma_ephem.py
• alma_ephem - Copy.py

The last file should not be part of the built distribution. So I deleted it (also deleting the two files in app/dist) and re-ran "python -m build". I did not notice until later that "alma_ephem - Copy.py" was still part of the distribution. In fact I found it cached in app/build/lib/pyalmanac/lib folder. ONLY AFTER DELETING THE app/build FOLDER entirely did the build run correctly.

I hope you have enough information to detect the issue, if not, I'll gladly be of further assistance. My suspicion is that only the first 10 characters (alma_ephem) are compared, which also matches "alma_ephem - Copy" so it thinks it should remain in the distribution set. Just guessing! Thanks for your assistance.

[layday]

Thanks for reporting. This is not an issue with build, which is just a frontend for other build tools - in this case, setuptools. The setuptools wheel builder merges the contents of the package folder it keeps in the "build" folder with every consecutive run (see pypa/wheel#147). To ensure that this does not happen in the future, delete your "build" folder before rebuilding.

[FFY00]

Exactly, pypa/build only invokes the backend, which is the one responsible for building the the actual distribution archives.

[aendie]

Thanks for the fast response. Okay, so if deleting the 'build' folder before running "python -m build" is required, why doesn't the "build" package do it for you? Is there a reason why we should do this manually?

[henryiii]

Setuptools decides this, how is build supposed to know it's safe to delete some folder? And this is setuptools specific, other build tools do different things, and build cannot/should not be in the business of manually "improving" them.

In general, you should be running build on a fresh checkout, probably in CI. Or always do a full git clean before running. Setuptools is really bad about picking up files that are not supposed to be there. Also I recommend running check-manifest.

[layday]

build doesn't even know the "build" folder exists.