--build_python_zip=false broken on Windows

[KoltesDigital]

🐞 bug report

Affected Rule

The issue is caused by the function **_transition_py_impl** so impacts **py_binary** and **py_test**.

Is this a regression?

The bug was not present with WORKSPACE method.

Description

I can't use --build_python_zip=false anymore.

However this might not be a bad thing. I've put that in .bazelrc a long time ago, when I had some troubles with caches. Maybe this is not needed anyway.

🔬 Minimal Reproduction

Any repo using rules_python with bzlmod on Windows, I guess.

🔥 Exception or Error

ERROR: C:/.../BUILD:X:X: in _transition_py_binary rule //:requirements.update:
Traceback (most recent call last):
        File "C:/.../external/rules_python~/python/config_settings/transition.bzl", line 57, column 28, in _transition_py_impl
                ctx.actions.symlink(
Error in symlink: Exactly one of "target_file" or "target_path" is required
ERROR: C:/.../BUILD:X:X: Analysis of target '//:requirements.update' failed

From what I understand, because zipfile is still None, because the previous loop didn't find any zip file in the runfiles.

🌍 Your Environment

Operating System: Windows 10 x64
Output of bazel version:

  
Build label: 7.1.1
Build target: @@//src/main/java/com/google/devtools/build/lib/bazel:BazelServer
Build time: Thu Mar 21 18:11:32 2024 (1711044692)
Build timestamp: 1711044692
Build timestamp as int: 1711044692
  

Rules_python version: 0.31.0

[KoltesDigital]

Well, now binaries/tests are incredibly slow. Good reminder why I was using it.

[KoltesDigital]

It may not be linked to bzlmod after all, because it only adds an extension of top of previous functions. Surely this is due to upgrading from 0.19.0 😄

[KoltesDigital]

Still not working with 0.32.2.

[aignas]

Could you test if this is still not working well with 0.29.0 please? That is before we switched to starlark implementation of the rules.

[KoltesDigital]

@aignas Well, I tried to bisect. The flag still works in version 0.25.0, with only bazel_dep in MODULE.bazel and the pip deps kept in WORKSPACE. But 0.26.0 had a weird dep cycle so I moved everything into MODULE.bazel, and then the flag doesn't work. So I couldn't tell if it's related to the version in itself, or to the switch to bzlmod.

As a side note, the code dealing with the zips has been added in 0.15.0.