The license field in pyproject.toml is incorrect

[abompard]

According to the documentation, thelicense field in pyproject.toml should be a SPDX license expression, and it's the license-files field that should contain paths to the license files.

In your case it should be:

[project]
license = "BSD-2-Clause"
license-files = ["LICENSE"]

[GrahamDumpleton]

And this PEP shows what I do as an example.

• https://peps.python.org/pep-0621/#example

From memory I originally had what you suggest but some tools would complain about it and what I used was all I could find that stopped them from complaining.

That said, later on I did find that when using uv publish to try and upload the built package to PyPi, uv would complain when uploading the package for old Python versions (3.8 and maybe 3.9). As a result I had to go back to using twine upload to publish to PyPi until can drop the old Python versions.

Can you tell me what tool you were using and what command for it to complain about the format being used for the license field?

[GrahamDumpleton]

Okay, so the section of separate docs more specific than section you gave is:

• https://peps.python.org/pep-0639/#deprecate-license-key-table-subkeys

I still though somehow have to contend with tools complaining/erroring when dealing with a large range of Python versions. If I leave the field out completely that then results in the license reference being missing when package listed on some sites.

Are you able to tell me with certainty what will work for Python versions 3.8 through to current versions?

[GrahamDumpleton]

Worth pointing out from the latter link is:

Likewise, if the new license-files key is not present and the file subkey is present in the license table, tools SHOULD issue a warning informing users it is deprecated and recommending the license-files key instead.

So with what I have any tool should only give a warning and not an error.

For now, given the range of Python versions I need to support and how various tools behave across versions, I may have to keep using what I am using until I can drop support for older Python versions.

[abompard]

Hey Graham, thanks for your responses.

Can you tell me what tool you were using and what command for it to complain about the format being used for the license field?

I'm using liccheck but I've seen it be a little "naive" when reading metadata in the past so I wouldn't use it as a reference implementation checking tool.

However the PyPI license field seems unusual:

Are you able to tell me with certainty what will work for Python versions 3.8 through to current versions?

No, I don't know. The only thing I can tell is that I'm checking for the licences of all dependencies in quite a few projects, and only wrapt is flagged like this.

For now, given the range of Python versions I need to support and how various tools behave across versions, I may have to keep using what I am using until I can drop support for older Python versions.

That's totally understandable, I'll just add an exception in my configuration. Thanks.

[VKovalchuk-danone]

Please also see that on the project page in the section
License
This project is licensed under the BSD License - see the LICENSE file for details.
has broken link as of 27-10-2025: https://pypi.org/project/wrapt/LICENSE/ (shows Error code 404)

[kapilt]

yeah. also seeing this, the resulting package in pypi metadata does not contain any license metadata in its dist-info METADATA file, just the copyright and license content verbatim, versus any spdx / shortform marker. this isn't about a specific version of python afaics, its about not missing packaging metadata on license specification. i was on 3.12 fwiw.

Metadata-Version: 2.4
Name: wrapt
Version: 2.0.0
Summary: Module for decorators, wrappers and monkey patching.
Home-page: https://github.com/GrahamDumpleton/wrapt
Author: Graham Dumpleton
Author-email: Graham Dumpleton <Graham.Dumpleton@gmail.com>
License: Copyright (c) 2013-2025, Graham Dumpleton
        All rights reserved.

        Redistribution and use in source and binary forms, with or without
        modification, are permitted provided that the following conditions are met:

        * Redistributions of source code must retain the above copyright notice, this
          list of conditions and the following disclaimer.

        * Redistributions in binary form must reproduce the above copyright notice,
          this list of conditions and the following disclaimer in the documentation
          and/or other materials provided with the distribution.

        THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
        AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
        LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
        CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
        SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
        INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
        CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
        ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
        POSSIBILITY OF SUCH DAMAGE.

Project-URL: Homepage, https://github.com/GrahamDumpleton/wrapt
Project-URL: Bug Tracker, https://github.com/GrahamDumpleton/wrapt/issues/
Project-URL: Changelog, https://wrapt.readthedocs.io/en/latest/changes.html
Project-URL: Documentation, https://wrapt.readthedocs.io/
Keywords: wrapper,proxy,decorator
Platform: any
Classifier: Development Status :: 5 - Production/Stable
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Classifier: Programming Language :: Python :: 3.12
Classifier: Programming Language :: Python :: 3.13
Classifier: Programming Language :: Python :: 3.14
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
Requires-Python: >=3.8
Description-Content-Type: text/markdown
License-File: LICENSE
Provides-Extra: dev
Requires-Dist: pytest; extra == "dev"
Requires-Dist: setuptools; extra == "dev"
Dynamic: license-file

[MartinRoth]

Hi, just to add to this. My license check only broke recently, so it might have to to with recent adaptations of the package. If BSD is correct, I will add this package to the allowed packages. And thanks @GrahamDumpleton for maintaining this! I can imagine that the python ecosystem does not make this simple!

[PhorstenkampFuzzy]

Our license checker also broke down and died. Could you release a patch?

[GrahamDumpleton]

You can test against develop branch to see if changes satisfy your requirement.

[PhorstenkampFuzzy]

Difficult since the tools data mine pypi. I will check if i can do the same with a local wheel.