setuptools breaking changes

84.1.0

2 breaking changes, first published October 19, 2026.

• Behavior changed setuptools.archive_util
  Archive members that would be extracted outside the extraction directory now raise UnsafeMember rather than being skipped. Code that relied on silent skipping must catch this exception. github.com
• Behavior changed Wheel.install_as_egg
  Entries in namespace_packages.txt are now validated as dotted module names on every platform, so entries that are absolute, drive-qualified or UNC paths are no longer accepted. This path is reached only by the deprecated setup_requires... github.com

84.0.0

33 breaking changes, first published August 8, 2026.

• Removed distutils.compat.consolidate_linker_args
  The temporary distutils.compat.consolidate_linker_args shim has been removed. Code importing it will fail. github.com
• Removed setuptools.tests
  setuptools.tests was removed in setuptools 84.0.0 pypi.org
• Removed spawn
  The MSVC spawn shim for third-party monkeypatches predating the env argument has been removed. github.com
• Behavior changed customize_compiler
  customize_compiler now raises AssertionError if CC, CXX, CFLAGS or similar config variables are None, instead of failing later. github.com
• Behavior changed CygwinCCompiler.gcc_version
  gcc_version now returns a packaging.version.Version instead of a distutils LooseVersion. Update code that relied on the old type. github.com
• Behavior changed distutils.errors.DistutilsPlatformError
  Building with a MACOSX_DEPLOYMENT_TARGET lower than the interpreter's value now raises PlatformError instead of DistutilsPlatformError. Catch the new class if you match the old one. github.com
• Behavior changed distutils.spawn.spawn
  distutils.spawn.spawn is now a thin wrapper around subprocess.check_call. It no longer resolves cmd[0] with shutil.which or injects MACOSX_DEPLOYMENT_TARGET. github.com
• Behavior changed UnixCCompiler.runtime_library_dir_option
  For GNU ld, runtime_library_dir_option now returns a list of flags instead of a single combined string. github.com
• Signature changed setuptools.command.alias.option_base.boolean_options
  Was boolean_options; now boolean_options: list[str]. pypi.org
• Signature changed setuptools.command.alias.option_base.user_options
  Was user_options; now user_options: list[tuple[str, str, str]] | list[tuple[str, str | None, str]]. pypi.org

And 23 more in this version.

83.0.0

3 breaking changes, first published July 4, 2026.

• Removed
  The release now requires Python 3.10 or later. Users on older Python versions must stay on an earlier setuptools release. github.com
• Removed dry_run
  The vendored distutils no longer supports dry_run. Code relying on dry_run behavior must be changed. github.com
• Behavior changed FileList
  Exclude, global-exclude, recursive-exclude and prune rules now also match non-ASCII file names stored in a different Unicode normalization form, so files previously included in the sdist may now be excluded. github.com

82.0.1

2 breaking changes, first published March 9, 2026.

• Signature changed setuptools.tests.test_setuptools.TestDepends.testModuleExtract
  Was def testModuleExtract(self); now def testModuleExtract(self, sample_module). pypi.org
• Signature changed setuptools.tests.test_setuptools.TestDepends.testRequire
  Was def testRequire(self); now def testRequire(self, sample_module). pypi.org

82.0.0

3 breaking changes, first published February 8, 2026.

• Removed pkg_resources
  pkg_resources is no longer shipped with setuptools. Use importlib.resources and importlib.metadata instead, or pin an older setuptools version if your code relies on it for namespace packages or other behavior. pypi.org
• Removed setuptools.tests.test_namespaces.TestNamespaces.test_packages_in_the_same_namespace_installed_and_cwd
  TestNamespaces.test_packages_in_the_same_namespace_installed_and_cwd was removed in setuptools 82.0.0 pypi.org
• Removed setuptools.tests.test_namespaces.TestNamespaces.test_pkg_resources_import
  TestNamespaces.test_pkg_resources_import was removed in setuptools 82.0.0 pypi.org

81.0.0

10 breaking changes, first published February 6, 2026.

• Removed setuptools.tests.test_core_metadata.egg_info
  setuptools.tests.test_core_metadata.egg_info was removed in setuptools 81.0.0 pypi.org
• Removed setuptools.tests.test_core_metadata.write_requirements
  setuptools.tests.test_core_metadata.write_requirements was removed in setuptools 81.0.0 pypi.org
• Renamed setuptools.tests.test_core_metadata.TestParityWithMetadataFromPyPaWheel.test_equivalent_output
  Use TestParityWithMetadataFromPyPaWheel.test_pkg_info_roundtrip instead. pypi.org
• Signature changed
  Some class and function signatures changed as a side effect of removing --dry-run, so derivative code may need compatibility shims to match the expected interface. github.com
• Signature changed setuptools.command.alias.edit_config
  Was def edit_config(filename, settings, dry_run=False) -> None; now def edit_config(filename, settings) -> None. pypi.org
• Signature changed setuptools.command.bdist_egg.make_zipfile
  Was def make_zipfile(zip_filename: StrPathT, base_dir, verbose: bool = False, dry_run: bool = False, compress=True, mode: _ZipFileMode = 'w') -> StrPathT; now def make_zipfile(zip_filename: StrPathT, base_dir, verbose: bool = False... pypi.org
• Signature changed setuptools.command.egg_info.edit_config
  Was def edit_config(filename, settings, dry_run=False) -> None; now def edit_config(filename, settings) -> None. pypi.org
• Signature changed setuptools.command.saveopts.edit_config
  Was def edit_config(filename, settings, dry_run=False) -> None; now def edit_config(filename, settings) -> None. pypi.org
• Signature changed setuptools.command.setopt.edit_config
  Was def edit_config(filename, settings, dry_run=False) -> None; now def edit_config(filename, settings) -> None. pypi.org
• Signature changed setuptools.tests.test_logging.test_verbosity_level
  Was def test_verbosity_level(tmp_path, monkeypatch, flag, expected_level); now def test_verbosity_level(tmp_path, monkeypatch, flags, expected_level). pypi.org

Check your code

These are the changes. To see which of them reach your code, scan a public repository, or have your coding agent call check_code with your manifest or lockfile over MCP. The API reads every change in every version, not only the newest. On Team and up, a fix pull request opens for the changes that reach a connected repository. Nothing merges or deploys.