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tarfile.TarFile.add() does not normalize symlink targets on Windows #151669
Description
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
Activity
[-]`tarfile.TYarFile.add()` does not normalize symlink targets on Windows[/-][+]`tarfile.TarFile.add()` does not normalize symlink targets on Windows[/+]picnixz commentedon Jun 27, 2026
Considering this affects
meson dist, I'm marking it as a release blocker to draw attention.cc @hugovk @encukou @eli-schwartz
eli-schwartz commentedon Jun 28, 2026
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:
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.
gh-151669: Normalize symlink targets in tarfile.TarFile.gettarinfo() (G…
[3.15] gh-151669: Normalize symlink targets in tarfile.TarFile.gettar…