Failing to use hatch-vcs with tox

[Midnighter]

I can't manage to have my package successfully installed in tox virtual environments. Example project:

dummy
├── pyproject.toml
├── src
│   └── dummy
│       └── __init__.py
└── tox.ini

pyproject.toml

[build-system]
build-backend = "hatchling.build"
requires = ["hatchling", "hatch-vcs"]

[project]
name = "dummy"
license = "Apache-2.0"
requires-python = ">=3.8"
dynamic = ["version"]

[tool.hatch.build]
packages = ["src/dummy"]

[tool.hatch.build.hooks.vcs]
version-file = "src/dummy/_version.py"

[tool.hatch.version]
source = "vcs"

tox.ini

[testenv:safety]
deps=
    safety
commands=
    safety check --full-report

The safety test environment will attempt to install the package but fails to find the _version.py file.

safety: install_package> python -I -m pip install --force-reinstall --no-deps /tmp/dummy/.tox/.tmp/package/4/dummy-0.1.dev0.tar.gz
Processing ./.tox/.tmp/package/4/dummy-0.1.dev0.tar.gz
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... error

  error: subprocess-exited-with-error

  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [28 lines of output]
      Traceback (most recent call last):
        File "/tmp/dummy/.tox/safety/lib/python3.11/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 144, in prepare_metadata_for_build_wheel
          hook = backend.prepare_metadata_for_build_wheel
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'hatchling.build' has no attribute 'prepare_metadata_for_build_wheel'

      During handling of the above exception, another exception occurred:

      Traceback (most recent call last):
        File "/tmp/dummy/.tox/safety/lib/python3.11/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 351, in <module>
          main()
        File "/tmp/dummy/.tox/safety/lib/python3.11/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 333, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/dummy/.tox/safety/lib/python3.11/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 148, in prepare_metadata_for_build_wheel
          whl_basename = backend.build_wheel(metadata_directory, config_settings)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-ur8e521q/overlay/lib/python3.11/site-packages/hatchling/build.py", line 56, in build_wheel
          return os.path.basename(next(builder.build(wheel_directory, ['standard'])))
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-ur8e521q/overlay/lib/python3.11/site-packages/hatchling/builders/plugin/interface.py", line 149, in build
          build_hook.initialize(version, build_data)
        File "/tmp/pip-build-env-ur8e521q/overlay/lib/python3.11/site-packages/hatch_vcs/build_hook.py", line 43, in initialize
          dump_version(self.root, self.metadata.version, self.config_version_file, template=self.config_template)
        File "/tmp/pip-build-env-ur8e521q/overlay/lib/python3.11/site-packages/setuptools_scm/__init__.py", line 77, in dump_version
          with open(target, "w") as fp:
               ^^^^^^^^^^^^^^^^^
      FileNotFoundError: [Errno 2] No such file or directory: '/tmp/pip-req-build-_dtxzxhd/src/dummy/_version.py'
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.
safety: exit 1 (2.81 seconds) /tmp/dummy> python -I -m pip install --force-reinstall --no-deps /tmp/dummy/.tox/.tmp/package/4/dummy-0.1.dev0.tar.gz pid=99151
.pkg: _exit> python /home/moritz/.pyenv/versions/3.11.0/envs/taxpasta/lib/python3.11/site-packages/pyproject_api/_backend.py True hatchling.build

tox ==4.3.3
hatch ==1.6.3
hatch-vcs ==0.3.0

[ofek]

Can you show more output? Also it would be helpful to see what options the safety environment has inherited from the base environment.

[Midnighter]

I can paste more output soon. I deliberately made this minimal example so you can quickly reproduce yourself, though. This is the entire content of the files (for this example) that reproduces my error.

[Midnighter]

Also, it doesn't matter what is run in the tox env. It's only about tox installing the package.

[Midnighter]

Pasted the full output but I encourage you to just try it out. Maybe I missed something obvious?

[ofek]

I will look into this tonight

[Midnighter]

Hi,
Were you able to get to the bottom of this? I'm trying to upgrade my cookiecutter from using setuptools + versioneer to hatchling + hatch-vcs and this issue is the only thing blocking me from making the switch.

[Midnighter]

If this is more than my inability to properly configure it. Should I open an issue instead?

[Midnighter]

The answer is to not define packages = ["src/dummy"] for [tool.hatch.build] which is like settings sources to ["src"] and also keeps only the final component ("dummy") for the distributed sources.

So a possible solution is to define this for the wheel target only and restrict what is included in the sdist as shown here.

Instead of including only the "src" directory one could also set tool.hatch.build.only-packages = true.

[ofek]

I was able to reproduce but I didn't have time to debug, thank you very much for this!