Support `license-files` as a list of strings in pyproject.toml

[Calvin-L]

The docs say:

The following files are always included and cannot be excluded:

• [...]
• All defined license-files

That links to PEP 639, which gives this example for license-files:

[project]
license-files = ["LICEN[CS]E*", "AUTHORS*"]

However, hatchling doesn't accept this, throwing

TypeError: Field `project.license-files` must be a table

Reading the relevant code it looks like hatchling wants license-files.globs = [...] instead, but I don't see anything in the the hatchling docs about that, and it disagrees with the PEP. I think hatchling should accept the simpler official license-files = list-of-globs format.

[rblank]

Recent changes in pyproject-hooks (1.2, released Sep 29) have worsened the situation. pip install --editable now fails if license-files is not an array:

Obtaining file:///home/joe/src/t-doc/common
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build editable ... done
  Installing backend dependencies ... done
  Preparing editable metadata (pyproject.toml) ... error
  error: subprocess-exited-with-error

  × Preparing editable metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [29 lines of output]
      Traceback (most recent call last):
        File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 195, in prepare_metadata_for_build_editable
          hook = backend.prepare_metadata_for_build_editable
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'hatchling.build' has no attribute 'prepare_metadata_for_build_editable'

      During handling of the above exception, another exception occurred:

      Traceback (most recent call last):
        File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 389, in <module>
          main()
        File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 373, in main
          json_out["return_val"] = hook(**hook_input["kwargs"])
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 204, in prepare_metadata_for_build_editable
          whl_basename = build_hook(metadata_directory, config_settings)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-s3zdoiys/overlay/lib/python3.12/site-packages/hatchling/build.py", line 83, in build_editable
          return os.path.basename(next(builder.build(directory=wheel_directory, versions=['editable'])))
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-s3zdoiys/overlay/lib/python3.12/site-packages/hatchling/builders/plugin/interface.py", line 90, in build
          self.metadata.validate_fields()
        File "/tmp/pip-build-env-s3zdoiys/overlay/lib/python3.12/site-packages/hatchling/metadata/core.py", line 266, in validate_fields
          self.core.validate_fields()
        File "/tmp/pip-build-env-s3zdoiys/overlay/lib/python3.12/site-packages/hatchling/metadata/core.py", line 1363, in validate_fields
          getattr(self, attribute)
        File "/tmp/pip-build-env-s3zdoiys/overlay/lib/python3.12/site-packages/hatchling/metadata/core.py", line 753, in license_files
          raise TypeError(message)
      TypeError: Field `project.license-files` must be an array
      [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.

At the same time, hatchling fails builds if it is an array.

* Getting build dependencies for sdist...
* Building sdist...
Traceback (most recent call last):
  File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 389, in <module>
    main()
  File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 373, in main
    json_out["return_val"] = hook(**hook_input["kwargs"])
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/pyproject_hooks/_in_process/_in_process.py", line 335, in build_sdist
    return backend.build_sdist(sdist_directory, config_settings)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/hatchling/build.py", line 34, in build_sdist
    return os.path.basename(next(builder.build(directory=sdist_directory, versions=['standard'])))
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/hatchling/builders/plugin/interface.py", line 90, in build
    self.metadata.validate_fields()
  File "/usr/lib/python3.12/site-packages/hatchling/metadata/core.py", line 266, in validate_fields
    self.core.validate_fields()
  File "/usr/lib/python3.12/site-packages/hatchling/metadata/core.py", line 1376, in validate_fields
    getattr(self, attribute)
  File "/usr/lib/python3.12/site-packages/hatchling/metadata/core.py", line 750, in license_files
    raise TypeError(message)
TypeError: Field `project.license-files` must be a table

ERROR Backend subprocess exited when trying to invoke build_sdist

So license-files is currently unusable.

[ofek]

The array is supported since last night https://github.com/pypa/hatch/pull/1790