pbr broke with removal of sys_executable and ScriptsWriter names

[tiran]

setuptools version

80.3.0

Python version

any

OS

any

Additional environment information

No response

Description

setuptools release 80.3.0 broke pbr. The pbr backend is commonly used, e.g. the entire OpenStack project is powered by pbr. Several years ago, setuptools 12.0 introduced the same regression.

Expected behavior

A new release of setuptools should never break existing and commonly used packages and backends.

How to Reproduce

pip wheel --no-cache --no-deps --no-binary :all: stevedore

Output

...
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 404, in _build_with_temp_dir
          self.run_setup()
          ~~~~~~~~~~~~~~^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 512, in run_setup
          super().run_setup(setup_script=setup_script)
          ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 317, in run_setup
          exec(code, locals())
          ~~~~^^^^^^^^^^^^^^^^
        File "<string>", line 19, in <module>
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/__init__.py", line 117, in setup
          return distutils.core.setup(**attrs)
                 ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/core.py", line 186, in setup
          return run_commands(dist)
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/core.py", line 202, in run_commands
          dist.run_commands()
          ~~~~~~~~~~~~~~~~~^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/dist.py", line 1002, in run_commands
          self.run_command(cmd)
          ~~~~~~~~~~~~~~~~^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/dist.py", line 1106, in run_command
          super().run_command(command)
          ~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/dist.py", line 1021, in run_command
          cmd_obj.run()
          ~~~~~~~~~~~^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/command/bdist_wheel.py", line 405, in run
          self.run_command("install")
          ~~~~~~~~~~~~~~~~^^^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/cmd.py", line 357, in run_command
          self.distribution.run_command(command)
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/dist.py", line 1106, in run_command
          super().run_command(command)
          ~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/dist.py", line 1021, in run_command
          cmd_obj.run()
          ~~~~~~~~~~~^^
        File "/tmp/pip-build-env-fob8wgry/normal/lib/python3.13/site-packages/pbr/packaging.py", line 243, in run
          return du_install.install.run(self)
                 ~~~~~~~~~~~~~~~~~~~~~~^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/command/install.py", line 700, in run
          self.run_command(cmd_name)
          ~~~~~~~~~~~~~~~~^^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/cmd.py", line 357, in run_command
          self.distribution.run_command(command)
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/dist.py", line 1106, in run_command
          super().run_command(command)
          ~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/tmp/pip-build-env-fob8wgry/overlay/lib/python3.13/site-packages/setuptools/_distutils/dist.py", line 1021, in run_command
          cmd_obj.run()
          ~~~~~~~~~~~^^
        File "/tmp/pip-build-env-fob8wgry/normal/lib/python3.13/site-packages/pbr/packaging.py", line 492, in run
          bs_cmd, 'executable', easy_install.sys_executable)
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'setuptools.command.easy_install' has no attribute 'sys_executable'
      [end of output]

[tiran]

The regression was introduced in 80.3.0. The same command passes when I pin setuptools==80.2.0 with PIP_CONSTRAINT=$(pwd)/constraint.txt.

[xtexx]

For Linux distro maintainers, applying this patch to pbr may solve this error.

[jaraco]

Several years ago, setuptools 12.0 introduced the same regression.

How is it that a regression was identified over 10 years ago, but the underlying risk was never addressed? I searched, but couldn't find where I'd been informed of the issues with pbr. Perhaps it came through IRC or Discord or something. Regardless, I would have expected the downstream dependency to have registered an issue and gotten it fixed in short order to remove this risk when it was identified. Surely it's not reasonable for Setuptools to carry this property around indefinitely.

This project has better tools and processes in place today to deprecate behaviors like these, but even those failed us. There is a pbr integration test, but it somehow doesn't trigger the failure. Maybe it's because only the 'editable' path was tested and not the non-editable form?

I might be convinced to re-add compatibility support for pbr for this property, but only if someone from pbr is willing to own the problem and help design the solution and regression test.

For Linux distro maintainers, applying this patch to pbr may solve this error.

Oh, this is interesting. It reveals that the dependency isn't merely on the sys_executable property, but also on the ScriptsWriter class and the get_script_args function. Hmm. It looks like get_script_args wasn't even a part of the implicated removal. I do agree, the removal of a seemingly public interface (ScriptsWriter) deserves some support and deprecation period.

I've yanked the release and I'll get a patch out that supplies these two properties (ScriptsWriter and sys_executable) for a short extension. I do have the intention to deprecate the ScriptsWriter also, but I don't yet know what that will entail.