[BUG] setuptools 77.0.2 legacy build_meta fails with TypeError

[reallistic]

setuptools version

setuptools==77.0.3

Python version

Python 3.10.16

OS

macos + ubuntu jammy

Additional environment information

$ uv --version
uv 0.6.8 (c1ef48276 2025-03-18)

Description

When attempting to build an sdist using uv the following error is displayed:

<see full output below>
running check
Traceback (most recent call last):
  File "<string>", line 11, in <module>
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/build_meta.py", line 449, in build_sdist
    return self._build_with_temp_dir(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/build_meta.py", line 407, in _build_with_temp_dir
    self.run_setup()
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/build_meta.py", line 320, in run_setup
    exec(code, locals())
  File "<string>", line 1, in <module>
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/__init__.py", line 117, in setup
    return distutils.core.setup(**attrs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/core.py", line 186, in setup
    return run_commands(dist)
           ^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/core.py", line 202, in run_commands
    dist.run_commands()
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 1002, in run_commands
    self.run_command(cmd)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/dist.py", line 1105, in run_command
    super().run_command(command)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 1021, in run_command
    cmd_obj.run()
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/command/sdist.py", line 67, in run
    self.run_command(cmd_name)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/cmd.py", line 357, in run_command
    self.distribution.run_command(command)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/dist.py", line 1105, in run_command
    super().run_command(command)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 1019, in run_command
    cmd_obj = self.get_command_obj(command)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 885, in get_command_obj
    cmd_obj = self.command_obj[command] = klass(self)
                                          ^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setupmeta/__init__.py", line 786, in meta_command_init
    setuptools.Command.__init__(self, dist, **kwargs)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/__init__.py", line 175, in __init__
    super().__init__(dist)
    ^^^^^^^
TypeError: super(type, obj): obj must be an instance or subtype of type
  × Failed to build `/Users/michase/workspace/ntflx/scratch/repro-setuptools-77-0-3`
  ├─▶ The build backend returned an error
  ╰─▶ Call to `setuptools.build_meta.build_sdist` failed (exit status: 1)
      hint: This usually indicates a problem with the package or the build environment.

Expected behavior

I expect the sdist to be generated without error.

How to Reproduce

First, ensure uv and python 3.10 are installed.

Use the following pyproject.toml file:

[project]
name = "repro-setuptools-7703"
version = "0.0.1"

[build-system]
requires = ["setuptools == 77.0.3", "setupmeta"]
build-backend = "setuptools.build_meta"

Command:

uv build --index-url https://pypi.org/simple -o . --sdist -p 3.10 .

Output

❯ uv build --index-url https://pypi.org/simple -o . --sdist -p 3.10 .
Building source distribution...
running egg_info
creating repro_setuptools_7703.egg-info
writing repro_setuptools_7703.egg-info/PKG-INFO
writing dependency_links to repro_setuptools_7703.egg-info/dependency_links.txt
writing top-level names to repro_setuptools_7703.egg-info/top_level.txt
writing manifest file 'repro_setuptools_7703.egg-info/SOURCES.txt'
reading manifest file 'repro_setuptools_7703.egg-info/SOURCES.txt'
writing manifest file 'repro_setuptools_7703.egg-info/SOURCES.txt'
running sdist
running egg_info
writing repro_setuptools_7703.egg-info/PKG-INFO
writing dependency_links to repro_setuptools_7703.egg-info/dependency_links.txt
writing top-level names to repro_setuptools_7703.egg-info/top_level.txt
reading manifest file 'repro_setuptools_7703.egg-info/SOURCES.txt'
writing manifest file 'repro_setuptools_7703.egg-info/SOURCES.txt'
warning: sdist: standard file not found: should have one of README, README.rst, README.txt, README.md

running check
Traceback (most recent call last):
  File "<string>", line 11, in <module>
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/build_meta.py", line 449, in build_sdist
    return self._build_with_temp_dir(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/build_meta.py", line 407, in _build_with_temp_dir
    self.run_setup()
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/build_meta.py", line 320, in run_setup
    exec(code, locals())
  File "<string>", line 1, in <module>
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/__init__.py", line 117, in setup
    return distutils.core.setup(**attrs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/core.py", line 186, in setup
    return run_commands(dist)
           ^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/core.py", line 202, in run_commands
    dist.run_commands()
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 1002, in run_commands
    self.run_command(cmd)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/dist.py", line 1105, in run_command
    super().run_command(command)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 1021, in run_command
    cmd_obj.run()
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/command/sdist.py", line 67, in run
    self.run_command(cmd_name)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/cmd.py", line 357, in run_command
    self.distribution.run_command(command)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/dist.py", line 1105, in run_command
    super().run_command(command)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 1019, in run_command
    cmd_obj = self.get_command_obj(command)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 885, in get_command_obj
    cmd_obj = self.command_obj[command] = klass(self)
                                          ^^^^^^^^^^^
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setupmeta/__init__.py", line 786, in meta_command_init
    setuptools.Command.__init__(self, dist, **kwargs)
  File "/Users/michase/.cache/uv/builds-v0/.tmpJ345uf/lib/python3.11/site-packages/setuptools/__init__.py", line 175, in __init__
    super().__init__(dist)
    ^^^^^^^
TypeError: super(type, obj): obj must be an instance or subtype of type
  × Failed to build `/Users/michase/workspace/ntflx/scratch/repro-setuptools-77-0-3`
  ├─▶ The build backend returned an error
  ╰─▶ Call to `setuptools.build_meta.build_sdist` failed (exit status: 1)
      hint: This usually indicates a problem with the package or the build environment.

[abravalheri]

It seems that setupmeta is trying to run setuptools.Command.__init__ on an instance of setupmeta.commands.CheckCommand which descends from distutils.command.check.check not setuptools.Command?

Which was the latest version of setuptools and setupmeta that this was working?

[reallistic]

Hello @abravalheri this worked on setuptools 77.0.1 and setupmeta 3.6.1. Most of the python builds at my company utilize setupmeta and setuptools and have been doing so for quite some time. I didn't notice the setupmeta line in the stack trace initially. If the issue is on their end I can open a ticket over there.

[abravalheri]

I tested with the following configuration to discard the hypothesis of involvement with v77.0.3:

> docker run --rm -it python:3.10-bookworm /bin/bash
python -m pip install 'uv==0.6.8'
mkdir /tmp/proj-7702 && cd /tmp/proj-7702

cat <<EOF > pyproject.toml
[project]
name = "repro-setuptools-7702"
version = "0.0.1"

[build-system]
requires = ["setuptools @ https://github.com/pypa/setuptools/archive/refs/tags/v77.0.2.zip", "setupmeta==3.6.1"]
build-backend = "setuptools.build_meta"
EOF

uv build --index-url https://pypi.org/simple -o . --sdist -p 3.10 .

Here we can see that using v77.0.2 results in the same build failure.

[abravalheri]

This is what changed between v77.0.1 and v77.0.2: v77.0.1...v77.0.2

The only thing that does not look completely unrelated is the changes in setuptools/_distutils/command/__init__.py, because it introduces a from . import check and adds check to __all__.

This change was proposed in pypa/distutils#345

But still, hard to understand why that would cause a problem.

---

Update, the change in setuptools/_distutils/command/__init__.py seems to be related to the problem somehow because if I run the following I can build the project successfully:

> docker run --rm -it python:3.10-bookworm /bin/bash
python -m pip install 'uv==0.6.8'

cd /tmp
wget https://github.com/pypa/setuptools/archive/refs/tags/v77.0.2.zip
unzip v77.0.2.zip

sed '/check/d' -i /tmp/setuptools-77.0.2/setuptools/_distutils/command/__init__.py

mkdir /tmp/proj-7702 && cd /tmp/proj-7702

cat <<EOF > pyproject.toml
[project]
name = "repro-setuptools-7702"
version = "0.0.1"

[build-system]
requires = ["setuptools @ file:///tmp/setuptools-77.0.2", "setupmeta==3.6.1"]
build-backend = "setuptools.build_meta"
EOF

uv build --index-url https://pypi.org/simple -o . --sdist -p 3.10 .

I can also see that a 6 months old version of setuptools/_distutils/command/__init__.py does not import check or include it in __all__: https://github.com/pypa/setuptools/blob/v75.2.0/setuptools/_distutils/command/__init__.py

I cannot understand how that would be related though.

/cc @Avasam for any thoughts

[abravalheri]

Weirdly, setuptools does patch distutils.core.Command = setuptools.Command in
https://github.com/pypa/setuptools/blob/v77.0.2/setuptools/monkey.py#L76.

I can also see that the check command original implementation inherits from distutils.core.Command so that explains why setupmeta expects to get away with running setuptools.Command.__init__ on an instance of setupmeta.commands.CheckCommand (which inherits from distutils.command.check.check and in turn from distutils.core.Command).

If I had to guess I would say that eagerly importing commands in pypa/distutils#345 changed the order of execution of the modules:

• before Explicit re-exports of submodules in distutils.command.__all__ distutils#345:
  setuptools.monkey.patch_all then distutils.command.*
• after Explicit re-exports of submodules in distutils.command.__all__ distutils#345:
  distutils.command.* then setuptools.monkey.patch_all

So in old versions at the moment that distutils.command.* needed to be executed, the monkeypath would have already taken place, so all command classes were inheriting from setuptools.Command. Now, this no longer happens.

That is my hypothesis (I may be wrong).

@Avasam does it make sense?

[Avasam]

I don't have time to look deeply into it over the weekend (currently running a charity event), but your last hypothesis @abravalheri makes sense to me.

I proposed this change to work towards not duplicating the _distutils type annotations in typeshed (and having pypa/distutils be the source of truth for everyone), but if it's causing unexpected behaviour, and the monkey-patching can't be adapted, then feel free to revert. With a comment though (and/or a test as well), describing the expectations from the special monkey patching going on. Because even pyright whines about this, and it causes tooling like mypy.stubtest to just fail. So I could see this accidentally coming back.

Later I can look into it if a simple if TYPE_CHECKING block to avoid runtime changes is sufficient for stubtest (I know it'll be enough for pyright's reportUnsupportedDunderAll, but stubtest does some runtime checks as well.)

[abravalheri]

In pypa/distutils#345 (comment), I added a snippet that seems to corroborate the idea that the eager imports change the outcome of the monkey patching:

> docker run --rm -it python:3.10-bookworm /bin/bash
python -m pip install 'setuptools==77.0.1'
python
>>> import setuptools
>>> from distutils.command.sdist import sdist
>>> sdist.__mro__
(<class 'distutils.command.sdist.sdist'>, <class 'setuptools.Command'>, <class 'distutils.cmd.Command'>, <class 'object'>)


python -m pip install 'setuptools @ https://github.com/pypa/setuptools/archive/refs/tags/v77.0.2.zip'
python
>>> import setuptools
>>> from distutils.command.sdist import sdist
>>> sdist.__mro__
(<class 'distutils.command.sdist.sdist'>, <class 'distutils.cmd.Command'>, <class 'object'>)

[zsimic]

Context around this usage/redefinition of the check command was mostly to show which files appear to have changed in the local git checkout (if any). Since setupmeta computes a version dynamically based off of git tags, a version can be computed as +dirty when there are git changes pending. Some repos would for example systematically invoke black formatter, not realizing that can lead to git pending changes, and wonder why a version is marked +dirty.

Best way I found back then was to from distutils.command.check import check and use that as basis for setupmeta's redefinition of the check command.

[abravalheri]

@jaraco, it seems that this needs to be handled in the context of the https://github.com/pypa/distutils repo.

Reported in pypa/distutils#351.