Add Support for 3.14 (and 3.13)

[paultiq]

Thank you for this project!

I took a moment to update the project to support 3.14:

• Fixed a PEP649 breaking issue with 3.14... this could use a good review.
• Updated the project to test all current (and upcoming) versions: 3.9 through 3.14, plus 3.14t and pypy3.11.

Housekeeping - optional:

• Dropped 3.7 and 3.8, since they're long EOL.
• Left support for 3.9, although it's EOL in a few weeks.
• Moved project to uv & uv-build
• Updated lock file to latests
• Updated gh actions
• Added pre-commits, although more could be added - ruff formatter has a lot of opinions.
• Added PYPI version classifiers
• Provided a placeholder for switching to pypi trusted publishers, if you want.
• Added badgers to readme for: pypi version, python versions, and a coverage report (also hooked into the action)

The first part w/ 3.14 support is really the purpose here, and I'm happy to roll back the housekeeping stuff if you want just the first part but not second part.

Thank you!

[skupr-anaconda]

Will it support marshmallow 4.0.0+? Because marshmallow 4.1.0 tested against Python 3.14 https://github.com/marshmallow-code/marshmallow/blob/4.1.0/CHANGELOG.rst#410-2025-11-01.

I think conda won't have py314 support for marshmallow <4.0.1:

conda search marshmallow

Loading channels: done
# Name                       Version           Build  Channel
marshmallow                   2.16.3            py_0  pkgs/main
marshmallow                    3.2.0            py_0  pkgs/main
marshmallow                    3.2.2            py_0  pkgs/main
marshmallow                    3.5.1            py_0  pkgs/main
marshmallow                    3.5.2            py_0  pkgs/main
marshmallow                    3.6.1            py_0  pkgs/main
marshmallow                    3.7.0            py_0  pkgs/main
marshmallow                    3.7.1            py_0  pkgs/main
marshmallow                    3.8.0            py_0  pkgs/main
marshmallow                    3.9.1    pyhd3eb1b0_0  pkgs/main
marshmallow                   3.10.0    pyhd3eb1b0_0  pkgs/main
marshmallow                   3.11.1    pyhd3eb1b0_0  pkgs/main
marshmallow                   3.12.0    pyhd3eb1b0_0  pkgs/main
marshmallow                   3.12.1    pyhd3eb1b0_0  pkgs/main
marshmallow                   3.12.2    pyhd3eb1b0_0  pkgs/main
marshmallow                   3.19.0 py310hca03da5_0  pkgs/main
marshmallow                   3.19.0 py311hca03da5_0  pkgs/main
marshmallow                   3.19.0 py312hca03da5_0  pkgs/main
marshmallow                   3.19.0 py313hca03da5_0  pkgs/main
marshmallow                   3.19.0  py38hca03da5_0  pkgs/main
marshmallow                   3.19.0  py39hca03da5_0  pkgs/main
marshmallow                    4.0.0 py310hca03da5_0  pkgs/main
marshmallow                    4.0.0 py311hca03da5_0  pkgs/main
marshmallow                    4.0.0 py312hca03da5_0  pkgs/main
marshmallow                    4.0.0 py313hca03da5_0  pkgs/main
marshmallow                    4.0.0  py39hca03da5_0  pkgs/main
marshmallow                    4.0.1 py310hca03da5_0  pkgs/main
marshmallow                    4.0.1 py310hca03da5_1  pkgs/main
marshmallow                    4.0.1 py311hca03da5_0  pkgs/main
marshmallow                    4.0.1 py311hca03da5_1  pkgs/main
marshmallow                    4.0.1 py312hca03da5_0  pkgs/main
marshmallow                    4.0.1 py312hca03da5_1  pkgs/main
marshmallow                    4.0.1 py313hca03da5_0  pkgs/main
marshmallow                    4.0.1 py313hca03da5_1  pkgs/main
marshmallow                    4.0.1 py314hca03da5_1  pkgs/main
marshmallow                    4.0.1  py39hca03da5_0  pkgs/main

This can affect the downstream packages langsmith -> langchain-core

[skupr-anaconda]

If I try to build dataclasses-json 0.6.7 with marshmallow 4.0.1 for py314 on osx-arm64, then I get this error in the test environment:

## Package Plan ##

  environment location: /Users/sss/opt/miniconda3/conda-bld/dataclasses-json_1766484508581/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_plac


The following NEW packages will be INSTALLED:

    attrs:             25.4.0-py314hca03da5_2
    bzip2:             1.0.8-h80987f9_6
    ca-certificates:   2025.12.2-hca03da5_0
    dataclasses-json:  0.6.7-py314hca03da5_1     local
    hypothesis:        6.142.3-py314hca03da5_2
    iniconfig:         2.1.0-py314hca03da5_0
    libcxx:            20.1.8-hd7fd590_1
    libexpat:          2.7.3-h50f4ffc_4
    libffi:            3.4.4-hca03da5_1
    libmpdec:          4.0.0-h80987f9_0
    libzlib:           1.3.1-h5f15de7_0
    lz4-c:             1.9.4-h313beb8_1
    marshmallow:       4.0.1-py314hca03da5_1
    mypy_extensions:   1.0.0-py314hca03da5_0
    ncurses:           6.5-hee39554_0
    openssl:           3.0.18-h9b4081a_0
    packaging:         25.0-py314hca03da5_1
    pip:               25.3-pyh0d26453_0
    pluggy:            1.5.0-py314hca03da5_0
    pytest:            7.4.4-py314hca03da5_0
    python:            3.14.2-h1858270_101_cp314
    python_abi:        3.14-2_cp314
    readline:          8.3-h0b18652_0
    simplejson:        3.20.2-py314haa24f5a_0
    sortedcontainers:  2.4.0-pyhd3eb1b0_0
    sqlite:            3.51.0-hab6afd1_0
    tk:                8.6.15-hcd8a7d5_0
    typing_extensions: 4.15.0-py314hca03da5_0
    typing_inspect:    0.9.0-py314hca03da5_0
    tzdata:            2025b-h04d1e81_0
    xz:                5.6.4-h80987f9_1
    zlib:              1.3.1-h5f15de7_0
    zstd:              1.5.7-h817c040_0

Preparing transaction: ...working... done
Verifying transaction: ...working... done
Executing transaction: ...working... done
export PREFIX=/Users/sss/opt/miniconda3/conda-bld/dataclasses-json_1766484508581/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_plac
export SRC_DIR=/Users/sss/opt/miniconda3/conda-bld/dataclasses-json_1766484508581/test_tmp
import: 'dataclasses_json'
import: 'dataclasses_json'
+ python -c 'from importlib.metadata import version; assert(version('\''dataclasses-json'\'')=='\''0.6.7'\'')'
+ pytest -v --ignore=gh_src/tests/test_annotations.py gh_src/tests
============================= test session starts ==============================
platform darwin -- Python 3.14.2, pytest-7.4.4, pluggy-1.5.0 -- $PREFIX/bin/python
cachedir: .pytest_cache
hypothesis profile 'default'
rootdir: $SRC_DIR
plugins: hypothesis-6.142.3
collecting ... collected 324 items / 1 error

==================================== ERRORS ====================================
________________ ERROR collecting gh_src/tests/test_metadata.py ________________
gh_src/tests/test_metadata.py:39: in <module>
    car_schema = Car.schema()
../_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_plac/lib/python3.14/site-packages/dataclasses_json/api.py:95: in schema
    return Schema(only=only,
E   TypeError: Schema.__init__() got an unexpected keyword argument 'context'
=============================== warnings summary ===============================
gh_src/tests/test_collection_of_unions.py:8
  $SRC_DIR/gh_src/tests/test_collection_of_unions.py:8: PytestCollectionWarning: cannot collect test class 'TestChild' because it has a __init__ constructor (from: gh_src/tests/test_collection_of_unions.py)
    @dataclass_json

gh_src/tests/test_collection_of_unions.py:14
  $SRC_DIR/gh_src/tests/test_collection_of_unions.py:14: PytestCollectionWarning: cannot collect test class 'TestOtherChild' because it has a __init__ constructor (from: gh_src/tests/test_collection_of_unions.py)
    @dataclass_json

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
=========================== short test summary info ============================
ERROR gh_src/tests/test_metadata.py - TypeError: Schema.__init__() got an une...
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
========================= 2 warnings, 1 error in 0.84s =========================
WARNING: Tests failed for dataclasses-json-0.6.7-py314hca03da5_1.conda - moving package to /Users/sss/opt/miniconda3/conda-bld/broken

CondaBuildUserError: TESTS FAILED: dataclasses-json-0.6.7-py314hca03da5_1.conda

[skupr-anaconda]

You can drop 3.9 https://devguide.python.org/versions/#status-of-python-versions

[paultiq]

See #568, it seems like there's noone left to approve PRs.

That's too bad.

* Nonetheless, I updated the project to drop 3.9. The marshmallow change should be another PR, if there's anyone left to approve anything here.