v0.16.1 installation fail - license format in pyproject.toml

[pavelToman]

Hello!

I think there is a problem with the format of license in pyproject.toml:

numcodecs/pyproject.toml

Line 36 in 4fdb625

license = "MIT"

The installation fails with:

Processing /tmp/vsc47063/easybuild/build/zarr/3.0.9/foss-2025a/numcodecs/numcodecs-0.16.1
  Preparing metadata (pyproject.toml): started
  Preparing metadata (pyproject.toml): finished with status 'error'
  error: subprocess-exited-with-error
  
  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [104 lines of output]
      [numcodecs] setting up Blosc extension
      [numcodecs] compiling Blosc extension with SSE2 support
      [numcodecs] compiling Blosc extension with AVX2 support
      [numcodecs] setting up Zstandard extension
      [numcodecs] setting up LZ4 extension
      [numcodecs] setting up compat extension
      [numcodecs] setting up shuffle extension
      [numcodecs] setting up vlen extension
      [numcodecs] setting up fletcher32 extension
      [numcodecs] setting up jenkins extension
      configuration error: `project.license` must be valid exactly by one definition (2 matches found):
      
          - keys:
              'file': {type: string}
            required: ['file']
          - keys:
              'text': {type: string}
            required: ['text']
      
      DESCRIPTION:
          `Project license <https://peps.python.org/pep-0621/#license>`_.
      
      GIVEN VALUE:
          "MIT"
      
      OFFENDING RULE: 'oneOf'
      
      DEFINITION:
          {
              "oneOf": [
                  {
                      "properties": {
                          "file": {
                              "type": "string",
                              "$$description": [
                                  "Relative path to the file (UTF-8) which contains the license for the",
                                  "project."
                              ]
                          }
                      },
                      "required": [
                          "file"
                      ]
                  },
                  {
                      "properties": {
                          "text": {
                              "type": "string",
                              "$$description": [
                                  "The license of the project whose meaning is that of the",
                                  "`License field from the core metadata",
                                  "<https://packaging.python.org/specifications/core-metadata/#license>`_."
                              ]
                          }
                      },
                      "required": [
                          "text"
                      ]
                  }
              ]
          }
      Traceback (most recent call last):
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
          ~~~~^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
                                   ~~~~^^^^^^^^^^^^^^^^^^^^^^^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 149, in prepare_metadata_for_build_wheel
          return hook(metadata_directory, config_settings)
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/build_meta.py", line 377, in prepare_metadata_for_build_wheel
          self.run_setup()
          ~~~~~~~~~~~~~~^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/build_meta.py", line 320, in run_setup
          exec(code, locals())
          ~~~~^^^^^^^^^^^^^^^^
        File "<string>", line 385, in <module>
        File "<string>", line 376, in run_setup
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/__init__.py", line 117, in setup
          return distutils.core.setup(**attrs)
                 ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/_distutils/core.py", line 157, in setup
          dist.parse_config_files()
          ~~~~~~~~~~~~~~~~~~~~~~~^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/dist.py", line 648, in parse_config_files
          pyprojecttoml.apply_configuration(self, filename, ignore_option_errors)
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/config/pyprojecttoml.py", line 72, in apply_configuration
          config = read_configuration(filepath, True, ignore_option_errors, dist)
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/config/pyprojecttoml.py", line 140, in read_configuration
          validate(subset, filepath)
          ~~~~~~~~^^^^^^^^^^^^^^^^^^
        File "/apps/gent/RHEL9/cascadelake-ib/software/Python/3.13.1-GCCcore-14.2.0/lib/python3.13/site-packages/setuptools/config/pyprojecttoml.py", line 61, in validate
          raise ValueError(f"{error}\n{summary}") from None
      ValueError: invalid pyproject.toml config: `project.license`.
      configuration error: `project.license` must be valid exactly by one definition (2 matches found):
      
          - keys:
              'file': {type: string}
            required: ['file']
          - keys:
              'text': {type: string}
            required: ['text']
      
      [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.

Seems the format from v0.15.1 is ok:

numcodecs/pyproject.toml

Line 40 in 3cf8ab1

license = { text = "MIT" }

See: https://peps.python.org/pep-0621/#license

[d-v-b]

what are you using to build the project? It seems significant that we had no trouble building the package for the 0.16.1 release

[d-v-b]

see #759 for a change (I'm not sure if this is a fix, since we aren't having trouble building the project)

[pavelToman]

I build it from source by pip install . (via EasyBuild).
Have python 3.13.1 and it seems as a problem with setuptools, I have v75.6.0 not 77.

I will go for 0.15.1 then.

[d-v-b]

over in #759 I see this:

configuration error: `project.license` must be string
  GIVEN VALUE:
      {
          "text": "MIT License"
      }

  OFFENDING RULE: 'type'

  DEFINITION:
      {
          "type": "string"
      }

so it looks like a difference in the build backends. I'm guessing the build backend for numcodecs is out of date.

[pavelToman]

Yes, thank you!