bpo-42112: ZipInfo.from_file removes only needed slashes

[matan1008]

https://bugs.python.org/issue42112

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[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[MaxwellDupre]

Everything looks ok; all tests pass. But there is zero documentation, not here, not in the original issue. Could you add some description please, possibly a test case? Also, don't see any test for this change, could add please?

[matan1008]

I added a test case in 348a679
And explained the issue in 30b5e4d
Since I am pretty new to submitting PRs to python, could you please be more specific?

[MaxwellDupre]

Ah yes I see it now:
test_reading_archive_member_starts_with_slash (test.test_zipfile.OtherTests) ... ok
Your changes are in from_file but the test is in Other.Tests
Is there a reason for that?

Ok, but the info for this change in minimalist in the extreme.

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[clytaemnestra]

Hey @matan1008, I'm triaging stale PRs and came across this one. I tested it on main and the issue reproduces there, so it really just needs tests and docs to get over the line.

Script to reproduce

mia@mias-MacBook-Pro repro % every-python run main -- python
Build for main not found, building now...
⠋ Built f4a726d
Python 3.15.0a8+ (heads/main:f4a726da402, Jun  8 2026, 12:51:26) [Clang 17.0.0 (clang-1700.0.13.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> with open("src.txt", "wb") as f:
...     f.write(b"hello world")
...
11
>>> with zipfile.ZipFile("arch.zip", "w") as zf:
...     zf.write("src.txt", "/directory/filename.txt")
...
>>> zf = zipfile.ZipFile("arch.zip")
>>> zf.namelist()
['directory/filename.txt']
>>> zf.read("/directory/filename.txt")
Traceback (most recent call last):
  File "<python-input-6>", line 1, in <module>
    zf.read("/directory/filename.txt")
    ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mia/.every-python/builds/f4a726da402fc0e18994f8b607302800db56f101/lib/python3.15/zipfile/__init__.py", line 1681, in read
    with self.open(name, "r", pwd) as fp:
         ~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Users/mia/.every-python/builds/f4a726da402fc0e18994f8b607302800db56f101/lib/python3.15/zipfile/__init__.py", line 1718, in open
    zinfo = self.getinfo(name)
  File "/Users/mia/.every-python/builds/f4a726da402fc0e18994f8b607302800db56f101/lib/python3.15/zipfile/__init__.py", line 1646, in getinfo
    raise KeyError(
        'There is no item named %r in the archive' % name)
KeyError: "There is no item named '/directory/filename.txt' in the archive"
>>> zf.read("directory/filename.txt")
b'hello world'

Are you still interested in finishing it off? Happy to leave it with you if so. If you've moved on, I'd be glad to pick it up and build on your patch (with full credit, of course), or if you'd rather, we can just close it out as stale. Whatever works best for you, just let me know!

Cc @savannahostrowski

[matan1008]

Hey @clytaemnestra!
I am so glad you looked at it, I totally forgot about the PR :)
I would really like to finish the PR, do you see anything other than a rebase, docs and tests that is required?

Thanks a lotttt!

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #33115758 | 📁 Comparing ec9c785 against main (f4f1020)

  🔍 Preview build  

488 files changed · ± 455 modified · - 33 deleted

± Modified

• about.html
• bugs.html
• glossary.html
• index.html
• license.html
• py-modindex.html
• c-api/allocation.html
• c-api/apiabiversion.html
• c-api/arg.html
• c-api/buffer.html
• and 445 more...

- Deleted

• improve-page-nojs.html
• improve-page.html
• _static/tachyon-example-flamegraph.html
• _static/tachyon-example-heatmap.html
• c-api/curses.html
• c-api/interp-lifecycle.html
• c-api/picklebuffer.html
• c-api/profiling.html
• c-api/sentinel.html
• c-api/slots.html
• and 23 more...

[matan1008]

How can I fix the CI issues?