python list: don't list system interpreters twice when directories are symlinked

[gotmax23]

Summary

$ cpython-3.13.2-linux-x86_64-gnu     /usr/bin/python3.13
cpython-3.13.2-linux-x86_64-gnu     /bin/python3.13
cpython-3.12.9-linux-x86_64-gnu     /usr/bin/python3.12
cpython-3.12.9-linux-x86_64-gnu     /usr/bin/python3 -> python3.12
cpython-3.12.9-linux-x86_64-gnu     /usr/bin/python -> ./python3
cpython-3.12.9-linux-x86_64-gnu     /bin/python3.12
cpython-3.12.9-linux-x86_64-gnu     /bin/python3 -> python3.12
cpython-3.12.9-linux-x86_64-gnu     /bin/python -> ./python3
cpython-3.11.11-linux-x86_64-gnu    /usr/bin/python3.11
cpython-3.11.11-linux-x86_64-gnu    /bin/python3.11
cpython-3.10.16-linux-x86_64-gnu    /usr/bin/python3.10
cpython-3.10.16-linux-x86_64-gnu    /bin/python3.10
cpython-3.9.21-linux-x86_64-gnu     /usr/bin/python3.9
cpython-3.9.21-linux-x86_64-gnu     /bin/python3.9
cpython-3.8.20-linux-x86_64-gnu     /usr/bin/python3.8
cpython-3.8.20-linux-x86_64-gnu     /bin/python3.8
cpython-3.7.9-linux-x86_64-gnu      .local/share/uv/python/cpython-3.7.9-linux-x86_64-gnu/bin/python3.7 -> python3.7m
pypy-3.10.16-linux-x86_64-gnu       /usr/bin/pypy3 -> pypy3.10
pypy-3.10.16-linux-x86_64-gnu       /bin/pypy3 -> pypy3.10
$ ls -ald /bin
lrwxrwxrwx. 1 root root 7 Jan 23  2024 /bin -> usr/bin

Platform

Linux 6.13.6-100.fc40.x86_64 x86_64 GNU/Linux

Version

uv 0.5.4

Python version

Python 3.12.9

[zanieb]

Related

• Show symbolic links in uv python list #5308
• uv python list shows duplicate symlinks #6690 (comment)

This is intentional, though this duplicate directory case is a fairly compelling one to de-duplicate (or a case to change the default).

[gotmax23]

Got it. Not that on some distributions /bin, /sbin, and /usr/sbin are all symlinks to /usr/bin.

[zanieb]

Yeah that seems far too noisy.

[gotmax23]

Yeah that seems far too noisy.

Yup. For the record, this is what it looks like in a Fedora Rawhide container (that has the bin-sbin merge) with all the available Pythons installed:

cpython-3.14.0a6-linux-x86_64-gnu    /usr/sbin/python3.14
cpython-3.14.0a6-linux-x86_64-gnu    /usr/bin/python3.14
cpython-3.14.0a6-linux-x86_64-gnu    /sbin/python3.14
cpython-3.14.0a6-linux-x86_64-gnu    /bin/python3.14
cpython-3.13.2-linux-x86_64-gnu      /usr/sbin/python3.13
cpython-3.13.2-linux-x86_64-gnu      /usr/sbin/python3 -> python3.13
cpython-3.13.2-linux-x86_64-gnu      /usr/sbin/python -> ./python3
cpython-3.13.2-linux-x86_64-gnu      /usr/bin/python3.13
cpython-3.13.2-linux-x86_64-gnu      /usr/bin/python3 -> python3.13
cpython-3.13.2-linux-x86_64-gnu      /usr/bin/python -> ./python3
cpython-3.13.2-linux-x86_64-gnu      /sbin/python3.13
cpython-3.13.2-linux-x86_64-gnu      /sbin/python3 -> python3.13
cpython-3.13.2-linux-x86_64-gnu      /sbin/python -> ./python3
cpython-3.13.2-linux-x86_64-gnu      /bin/python3.13
cpython-3.13.2-linux-x86_64-gnu      /bin/python3 -> python3.13
cpython-3.13.2-linux-x86_64-gnu      /bin/python -> ./python3
cpython-3.12.9-linux-x86_64-gnu      /usr/sbin/python3.12
cpython-3.12.9-linux-x86_64-gnu      /usr/bin/python3.12
cpython-3.12.9-linux-x86_64-gnu      /sbin/python3.12
cpython-3.12.9-linux-x86_64-gnu      /bin/python3.12
cpython-3.11.11-linux-x86_64-gnu     /usr/sbin/python3.11
cpython-3.11.11-linux-x86_64-gnu     /usr/bin/python3.11
cpython-3.11.11-linux-x86_64-gnu     /sbin/python3.11
cpython-3.11.11-linux-x86_64-gnu     /bin/python3.11
cpython-3.10.16-linux-x86_64-gnu     /usr/sbin/python3.10
cpython-3.10.16-linux-x86_64-gnu     /usr/bin/python3.10
cpython-3.10.16-linux-x86_64-gnu     /sbin/python3.10
cpython-3.10.16-linux-x86_64-gnu     /bin/python3.10
cpython-3.9.21-linux-x86_64-gnu      /usr/sbin/python3.9
cpython-3.9.21-linux-x86_64-gnu      /usr/bin/python3.9
cpython-3.9.21-linux-x86_64-gnu      /sbin/python3.9
cpython-3.9.21-linux-x86_64-gnu      /bin/python3.9
pypy-3.11.11-linux-x86_64-gnu        /usr/sbin/pypy3 -> pypy3.11
pypy-3.11.11-linux-x86_64-gnu        /usr/bin/pypy3 -> pypy3.11
pypy-3.11.11-linux-x86_64-gnu        /sbin/pypy3 -> pypy3.11
pypy-3.11.11-linux-x86_64-gnu        /bin/pypy3 -> pypy3.11

Indeed very noisy.

[zanieb]

I think we can handle this with is_same_file on directories during PATH iteration — that's quadratic though 🤔. I can't think of why we'd want to discover these all as separate interpreters in any case?

@BurntSushi random but perhaps you have an intuition for how to do that well?

[BurntSushi]

@zanieb If I'm understanding correctly here, I believe that's where same-file::Handle should come in handy. You can get one of those for each path you want to consider and stuff them in a HashSet. This would avoid needing to do pairwise equality checks for all pairs of paths.

The downside is that they all need to be open file handles. Depending on how many you have, this can run afoul of max open file descriptor limits (which will vary from system to system).

[zanieb]

Cool thanks, that's exactly the kind of thing I was looking for.