Declare the MIT license as an SPDX expression

[mikkel]

Summary

python -m build with current setuptools (84.0.0) warned that the project.license table and the License :: OSI Approved :: MIT License classifier are deprecated and unsupported after 2027-02-18.

pyproject.toml now uses the current form:

• license = "MIT" (SPDX license expression)
• license-files = ["LICENSE.txt"]
• the License classifier is removed
• the build backend requirement is setuptools>=77, the first release that accepts those fields

Version stays 0.9.3. Nothing is published.

Build output before

python -m build succeeded, but setuptools printed these warnings while building both the sdist and the wheel (the classifier warning twice per phase):

WARNING `project.license` as a TOML table is deprecated
!!

        ********************************************************************************
        Please use a simple string containing a SPDX expression for `project.license`. You can also use `project.license-files`. (Both options available on setuptools>=77.0.0).

        By 2027-Feb-18, you need to update your project and remove deprecated calls
        or your builds will no longer be supported.

        See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
        ********************************************************************************

!!
WARNING License classifiers are deprecated.
!!

        ********************************************************************************
        Please consider removing the following classifiers in favor of a SPDX license expression:

        License :: OSI Approved :: MIT License

        See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
        ********************************************************************************

!!
Successfully built patchling-0.9.3.tar.gz and patchling-0.9.3-py3-none-any.whl

Build dependencies in that run: setuptools==84.0.0, wheel==0.48.0.

Build output after

Same command, same setuptools and wheel. No setuptools license warnings. The only WARNING line is from the build frontend itself (Both NO_COLOR and FORCE_COLOR environment variables are set, disabling color), which is unrelated to packaging metadata.

* Creating isolated environment: venv+pip...
* Installing packages in isolated environment:
  - setuptools>=77
  - wheel
* Getting build dependencies for sdist...
running egg_info
...
adding license file 'LICENSE.txt'
...
* Installed build dependency versions:
  - setuptools==84.0.0
  - wheel==0.48.0
* Building sdist...
...
* Building wheel from sdist
* Creating isolated environment: venv+pip...
* Installing packages in isolated environment:
  - setuptools>=77
  - wheel
...
* Installed build dependency versions:
  - setuptools==84.0.0
  - wheel==0.48.0
* Building wheel...
...
adding 'patchling-0.9.3.dist-info/licenses/LICENSE.txt'
adding 'patchling-0.9.3.dist-info/METADATA'
...
Successfully built patchling-0.9.3.tar.gz and patchling-0.9.3-py3-none-any.whl

twine check dist/*:

Checking dist/patchling-0.9.3-py3-none-any.whl: PASSED
Checking dist/patchling-0.9.3.tar.gz: PASSED

METADATA diff

Compared the rebuilt wheel with the published patchling 0.9.3 wheel (patchling-0.9.3-py3-none-any.whl). The license is still MIT. PEP 639 records it as License-Expression instead of the deprecated License field plus License classifier. License-File: LICENSE.txt is unchanged, the packaged LICENSE.txt bytes match (sha256 cc2264ef2518a4c8c5be58a98b574ab5a96317c59d6763404a77416186d4f016), and the description body is identical.

--- pypi-patchling-0.9.3 METADATA
+++ rebuilt-patchling-0.9.3 METADATA
@@ -3,14 +3,13 @@
 Version: 0.9.3
 Summary: Natural-language code transformation as a library: generate unified diffs with LLMs and apply them resiliently with smartapply. Formerly gptdiff.
 Author: 255labs
-License: MIT
+License-Expression: MIT
 Project-URL: Homepage, https://github.com/255BITS/patchling-py
 Project-URL: Documentation, https://255bits.github.io/patchling-py
 Project-URL: Source, https://github.com/255BITS/patchling-py
 Project-URL: Browser/Node runtime (npm), https://www.npmjs.com/package/patchling
 Project-URL: Built with patchling (nanoodle), https://nanoodle.com
 Keywords: patchling,smartapply,llm,diff,unified-diff,patch,code-transformation,ai,codegen,gptdiff
-Classifier: License :: OSI Approved :: MIT License
 Classifier: Programming Language :: Python :: 3
 Classifier: Operating System :: OS Independent
 Requires-Python: >=3.10

Tests

Offline suite, with LIVE_LLM and LLM/NanoGPT API keys unset. Live tests skipped:

195 passed, 2 skipped in 4.40s
SKIPPED tests/test_live_llm.py: live LLM tests are opt-in; set LIVE_LLM=1 and GPTDIFF_LLM_API_KEY
SKIPPED tests/test_relevance_live.py: set LIVE_LLM=1 to call the live LLM