Description

dnicolodi

opened on Jun 18, 2026

Issue body actions

Bug report

Bug description:

In #138309 tarfile.TarFile.extract() has been modified to replace / in symlink targets with \ on Windows. I believe that the opposite normalization should be done in tarfile.TarFile.add().

I have noticed this in a downstream project that extracts tar archives generated by git dist, adds some additional files, and recreates the archive. When the git repository contains a symbolic link, the repacked archive contains symbolic link with the wrong path separators.

Before #138309, the extracted symbolic links on Windows were not functional (I believe) but the repacked archive had the same content as the original one. After #138309, this is not true anymore.

CPython versions tested on:

3.15

Operating systems tested on:

Windows

Linked PRs

• gh-151669: Normalize symlink targets in tarfile.TarFile.gettarinfo() #151671
• [3.15] gh-151669: Normalize symlink targets in tarfile.TarFile.gettarinfo() (GH-151671) #153517

Activity

1. dnicolodi

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jun 18, 2026
2. aisk

   added

   OS-windows

   on Jun 19, 2026
3. aisk

   added this to Tarfile issues 🗄️on Jun 19, 2026
4. aisk

   changed the title [-]`tarfile.TYarFile.add()` does not normalize symlink targets on Windows[/-] [+]`tarfile.TarFile.add()` does not normalize symlink targets on Windows[/+] on Jun 19, 2026
5. picnixz

   added

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   release-blocker

   on Jun 27, 2026
6. github-project-automation

   added this to Release and Deferred blockers 🚫on Jun 27, 2026
7. github-project-automation

   moved this to Todo in Release and Deferred blockers 🚫on Jun 27, 2026
8. picnixz commented on Jun 27, 2026

   

   picnixz

   on Jun 27, 2026

   Member

   More actions

   Considering this affects meson dist, I'm marking it as a release blocker to draw attention.

   cc @hugovk @encukou @eli-schwartz
9. eli-schwartz commented on Jun 28, 2026

   

   eli-schwartz

   on Jun 28, 2026

   Contributor

   More actions

   Thanks. I'm subscribed to this ticket but most of the discussion seems to have been happening appended to #138309 (which I'm also subscribed to).

   From the meson side, I had this comment:

   If I understand correctly, using tarfile on windows to create an archive has always been wrong by default, but previously when taking a git generated tar, it was possible to roundtrip (unpack and repack) while preserving the target location set by git archive. And the roundtripping now causes a problem because unpacking will "destroy" information?

   Of course destroying information (that did not used to be destroyed) is a regression. But the discussion from the older PR has not been looking promising, unfortunately. :(

   I do hope this gets solved before final release, but a suitable fallback might, I suppose, be that meson dist can simply reject running on the combination of windows + 3.15 with an error message pointing to this ticket. I understand that that might be problematic to people whose build backend relies on a working tarfile module, but the good news is that many python developers just do releases via SaaS cloud providers (notably GitHub Actions) and aren't necessarily affected in the first place.
10. encukou

    added a commit that references this issue on Jul 10, 2026

    gh-151669: Normalize symlink targets in tarfile.TarFile.gettarinfo() (G…

    cc31641
11. hugovk

    added a commit that references this issue on Jul 17, 2026

    [3.15] gh-151669: Normalize symlink targets in tarfile.TarFile.gettar…

    fefc0b4
12. hugovk

    closed this as completedon Jul 17, 2026
13. github-project-automation

    moved this from Todo to Done in Release and Deferred blockers 🚫on Jul 17, 2026
14. github-project-automation

    moved this to Done in Tarfile issues 🗄️on Jul 17, 2026

Issue actions