Add a .gitignore file to each __pycache__ folder

[gvanrossum]

Feature or enhancement

Proposal:

When creating a __pycache__ folder, add a .gitignore file with the content

# Created by CPython
*

I've seen this pattern appear in a few places (coverage.py's htmlcov folder, .venv, .pytest_cache) and it saves projects from having to add such things to their main .gitignore.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-141081: Add a .gitignore file to __pycache__ folders #141162
• gh-141081: Don't create .gitignore in site-packages #142745
• gh-141081: Revert "Add a .gitignore file to __pycache__ folders (#141162)" #142758

[serhiy-storchaka]

Is not __pycache__ in a single top-level .gitignore file enough?

[hugovk]

Similarly, we added a .gitignore to venv dirs in 3.13: #83417.

[gvanrossum]

Is not __pycache__ in a single top-level .gitignore file enough?

But that would have to be added by every user for every repo.

I would like the repo .gitignore to be about artifacts of the software in the repo, not artifacts of tools if we can avoid it.

[zware]

Creating it ourselves also sends a clear signal that you really shouldn't be checking this stuff in.

[brettcannon]

My biggest question is how do we document this (I'm sure someone somewhere is checking in their __pycache__ files on purpose)? I'm assuming we will tweak this as we just deem reasonable based on whatever VCS is most popular at the time, but we should be clear in the docs that what's supported can change and there won't be any warning beyond What's New.

[gvanrossum]

Did we update any docs for the venv module when we added the same thing there?

Is __pycache__ documented at all? Wherever that is, is where the docs should be updated for this.

[hugovk]

Did we update any docs for the venv module when we added the same thing there?

We added a --without-scm-ignore-files flag and a scm_ignore_files parameter and documented those:

• https://github.com/python/cpython/pull/108125/files
• https://docs.python.org/3/library/venv.html

Although the What's New is the best overview:

• https://docs.python.org/3/whatsnew/3.13.html#venv

Did we update any docs for the venv module when we added the same thing there?

Is __pycache__ documented at all? Wherever that is, is where the docs should be updated for this.

It's mentioned on a dozen pages but doesn't seem to have its own "home":

• https://docs.python.org/3/search.html?q=__pycache__

Perhaps this would be a good place to put it:

• https://docs.python.org/3/tutorial/modules.html#compiled-python-files

---

There's a PR up at #141162.

[nanonyme]

This sounds like unnecessary noise for things like container images. There are tons of repository templates including in GitHub which will initialize your repo with top-level .gitignore for Python.

[nanonyme]

If this is done, please make it opt-outable at least. I am quite surprised also to hear that venv went ahead with this feature.

[hugovk]

It's opt-out for venv using --without-scm-ignore-files:

https://docs.python.org/3/library/venv.html#cmdoption-venv-without-scm-ignore-files

[nanonyme]

I was referring to if adding this became a Python default, not just venv. There should really be an opt-out.