Commit 0fb4ce12f0637077ea9a1064f6447d3aa81c6ffa breaks py_binary bootstrap wrapper for Python 2

[pw-mdb]

🐞 bug report

Description

Commit 0fb4ce1 / PR #2481 breaks the py_binary bootstrap wrapper for systems that have Python 2 as the system Python. Reverting that commit fixes the issue.

Is this a regression?

Yes, regression as of commit 0fb4ce1. Commit was first released in version 1.1.0.

🔬 Minimal Reproduction

1. Create a py_binary.
2. Try to run it on a Linux system that has Python 2 as the system Python.

🔥 Exception or Error

  File ".runfiles/_main/build/tools/yamllint", line 92
    def print_verbose(*args, mapping=None, values=None):
                                   ^
SyntaxError: invalid syntax

🌍 Your Environment

Operating System:

  
amazonlinux2
  

Output of bazel version:

  
Bazelisk version: 1.25.0
Build label: 8.1.1
Build target: @@//src/main/java/com/google/devtools/build/lib/bazel:BazelServer
Build time: Tue Feb 25 18:53:44 2025 (1740509624)
Build timestamp: 1740509624
Build timestamp as int: 1740509624
  

Rules_python version:

  
1.0.0
  

[pw-mdb]

Related: #2727

[rickeylev]

This is WAI. We no longer support python 2.

To work around this, you'll need to setup a custom toolchain and probably need to copy/paste the bootstrap and modify it to work with python 2. We have some docs to help walk through setting up a custom toolchain: https://rules-python.readthedocs.io/en/latest/toolchains.html#custom-toolchains

Setting --bootstrap_impl=script might work around this, assuming the program is using a python3 interpreter from its runfiles (or elsewhere). See https://rules-python.readthedocs.io/en/latest/api/rules_python/python/config_settings/index.html#bootstrap_impl

HTH!

[pw-mdb]

@rickeylev Thank you for the pointers! I will follow up about --bootstrap_impl=script on the other issue. To be clear, the issue here is that commit 0fb4ce1 breaks the py_binary bootstrap wrapper for a system Python 2, even if the py_binary is Python 3. Are you saying system Python 2 is no longer supported at all?