Implement PEP 794 (Import Name Metadata) by brettcannon · Pull Request #948 · pypa/packaging

brettcannon · 2025-10-20T18:58:20Z

Closes #945

…to pep-794

henryiii · 2025-10-24T14:05:57Z

In working on pypa/pyproject-metadata#260, I've thought of a few extra checks that might make sense there, or in both places:

Verify no names gets listed twice (combining both fields)
Verify that 'spam.bacon.eggs' has 'spam' and 'spam.bacon' listed somewhere too. This is described in the PEP, but there's no all-caps SHOULD or similar for it.
I think any package that is listed in import-names should not have any children listed. If you have a 'spam' in import-names, then you don't need to list 'spam.bacon.eggs'? Not sure on that one, haven't implemented it.

henryiii · 2025-10-24T15:28:25Z

I think this should test the empty Import-Name case - that's a very special case. It's the only place where an empty field is written; I know because I had to update the writer for pyproject-metadata to differentiate None vs. empty string to get this to write out there. Not sure where to test it though, everything.metadata just checks the ability of the email module to read it, it's not testing Metadata for example. I'm almost sure the as_rfc822 method will not write this correctly, it's a special case there too (writing an empty list as one empty element).

henryiii · 2025-10-24T15:51:25Z

I've got a patch ready that adds testing and fixes both directions of the special case. Would you like me to push it directly or make a PR?

brettcannon · 2025-10-24T17:18:22Z

I've got a patch ready that adds testing and fixes both directions of the special case. Would you like me to push it directly or make a PR?

Wonderful! Just push it to the PR.

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

brettcannon · 2025-10-24T22:40:16Z

Thanks for the improvements, @henryiii !

This PR contains the following updates: | Package | Type | Update | Change | |---|---|---|---| | [packaging](https://github.com/pypa/packaging) | packages | major | `==25.0` → `==26.0` | --- ### Release Notes <details> <summary>pypa/packaging (packaging)</summary> ### [`v26.0`](https://github.com/pypa/packaging/releases/tag/26.0) [Compare Source](pypa/packaging@25.0...26.0) Read about the performance improvements here: <https://iscinumpy.dev/post/packaging-faster>. #### What's Changed Features: - PEP 751: support pylock by [@sbidoul](https://github.com/sbidoul) in [#900](pypa/packaging#900) - PEP 794: import name metadata by [@brettcannon](https://github.com/brettcannon) in [#948](pypa/packaging#948) - Support writing metadata by [@henryiii](https://github.com/henryiii) in [#846](pypa/packaging#846) - Support `__replace__` for `Version` by [@henryiii](https://github.com/henryiii) in [#1003](pypa/packaging#1003) - Support positional pattern matching for `Version` and `Specifier` by [@henryiii](https://github.com/henryiii) in [#1004](pypa/packaging#1004) Behavior adaptations: - PEP 440 handling of prereleases for `Specifier.contains`, `SpecifierSet.contains`, and `SpecifierSet.filter` by [@notatallshaw](https://github.com/notatallshaw) in [#897](pypa/packaging#897) - Handle PEP 440 edge case in `SpecifierSet.filter` by [@notatallshaw](https://github.com/notatallshaw) in [#942](pypa/packaging#942) - Adjust arbitrary equality intersection preservation in `SpecifierSet` by [@notatallshaw](https://github.com/notatallshaw) in [#951](pypa/packaging#951) - Return `False` instead of raising for `.contains` with invalid version by [@Liam-DeVoe](https://github.com/Liam-DeVoe) in [#932](pypa/packaging#932) - Support arbitrary equality on arbitrary strings for `Specifier` and `SpecifierSet`'s `filter` and `contains` method. by [@notatallshaw](https://github.com/notatallshaw) in [#954](pypa/packaging#954) - Only try to parse as `Version` on certain marker keys, return `False` on unequal ordered comparsions by [@JP-Ellis](https://github.com/JP-Ellis) in [#939](pypa/packaging#939) Fixes: - Update `_hash` when unpickling `Tag()` by [@dholth](https://github.com/dholth) in [#860](pypa/packaging#860) - Correct comment and simplify implicit prerelease handling in `Specifier.prereleases` by [@notatallshaw](https://github.com/notatallshaw) in [#896](pypa/packaging#896) - Use explicit `_GLibCVersion` `NamedTuple` in `_manylinux` by [@cthoyt](https://github.com/cthoyt) in [#868](pypa/packaging#868) - Detect invalid license expressions containing `()` by [@bwoodsend](https://github.com/bwoodsend) in [#879](pypa/packaging#879) - Correct regex for metadata `'name'` format by [@di](https://github.com/di) in [#925](pypa/packaging#925) - Improve the message around expecting a semicolon by [@pradyunsg](https://github.com/pradyunsg) in [#833](pypa/packaging#833) - Support nested parens in license expressions by [@Liam-DeVoe](https://github.com/Liam-DeVoe) in [#931](pypa/packaging#931) - Add space before at symbol in `Requirements` string by [@henryiii](https://github.com/henryiii) in [#953](pypa/packaging#953) - A root logger use found by ruff LOG, use `packaging` logger instead by [@henryiii](https://github.com/henryiii) in [#965](pypa/packaging#965) - Better support for subclassing `Marker` and `Requirement` by [@henryiii](https://github.com/henryiii) in [#1022](pypa/packaging#1022) - Normalize all extras, not just if it comes first by [@henryiii](https://github.com/henryiii) in [#1024](pypa/packaging#1024) - Don't produce a broken repr if `Marker` fails to construct by [@henryiii](https://github.com/henryiii) in [#1033](pypa/packaging#1033) Performance: - Avoid recompiling regexes in the tokenizer for a 3x speedup by [@hauntsaninja](https://github.com/hauntsaninja) in [#1019](pypa/packaging#1019) - Improve performance in `_manylinux.py` by [@cthoyt](https://github.com/cthoyt) in [#869](pypa/packaging#869) - Minor cleanups to `Version` by [@bearomorphism](https://github.com/bearomorphism) in [#913](pypa/packaging#913) - Skip redundant creation of `Version`s in specifier comparison by [@notatallshaw](https://github.com/notatallshaw) in [#986](pypa/packaging#986) - Cache `Specifier`'s Version by [@notatallshaw](https://github.com/notatallshaw) in [#985](pypa/packaging#985) - Make `Version` a little faster by [@henryiii](https://github.com/henryiii) in [#987](pypa/packaging#987) - Minor `Version` regex cleanup by [@henryiii](https://github.com/henryiii) in [#990](pypa/packaging#990) - Faster regex on Python 3.11.5+ by [@henryiii](https://github.com/henryiii) in [#988](pypa/packaging#988) and [#1055](pypa/packaging#1055) - Lazily calculate `_key` in `Version` by [@notatallshaw](https://github.com/notatallshaw) in [#989](pypa/packaging#989) and regression for `packaging_legacy` fixed by [@henryiii](https://github.com/henryiii) in [#1048](pypa/packaging#1048) - Faster `canonicalize_version` by [@henryiii](https://github.com/henryiii) in [#993](pypa/packaging#993) - Use `fullmatch` in a couple more places by [@henryiii](https://github.com/henryiii) in [#992](pypa/packaging#992) - Use `fullmatch` for markers too by [@henryiii](https://github.com/henryiii) in [#1029](pypa/packaging#1029) - Use `map` instead of generator by [@henryiii](https://github.com/henryiii) in [#996](pypa/packaging#996) - Deprecate `._version` (`_Version`, a `NamedTuple`) by [@henryiii](https://github.com/henryiii) in [#995](pypa/packaging#995) and [#1062](pypa/packaging#1062) - Avoid duplicate `Version` creation in `canonicalize_version` by [@henryiii](https://github.com/henryiii) in [#994](pypa/packaging#994) - Add `__slots__` to `Version` by [@henryiii](https://github.com/henryiii) in [#1001](pypa/packaging#1001) - Add `__slots__` to `Specifier`s by [@henryiii](https://github.com/henryiii) in [#1002](pypa/packaging#1002) - Add `__slots__` to `Node`s by [@henryiii](https://github.com/henryiii) in [#1032](pypa/packaging#1032) - Use `version.__replace__` in specifier comparison by [@notatallshaw](https://github.com/notatallshaw) in [#999](pypa/packaging#999) - Use `_get_spec_version` in more places in `Specifier` by [@notatallshaw](https://github.com/notatallshaw) in [#1005](pypa/packaging#1005) - Pull `set` construction out of function by [@henryiii](https://github.com/henryiii) in [#1012](pypa/packaging#1012) - Letter normalization dict for prereleases and the like by [@henryiii](https://github.com/henryiii) in [#1014](pypa/packaging#1014) - Avoid normalizing extras again when comparing by [@henryiii](https://github.com/henryiii) in [#1028](pypa/packaging#1028) - Speed up `Version.__str__` by about 10% by [@henryiii](https://github.com/henryiii) in [#997](pypa/packaging#997) - Increase the performance of `canonicalize_name` by avoiding a regex by [@henryiii](https://github.com/henryiii) in [#1030](pypa/packaging#1030), [#1047](pypa/packaging#1047), and [#1064](pypa/packaging#1064) - Faster zero stripping by [@henryiii](https://github.com/henryiii) in [#1058](pypa/packaging#1058) Type annotations: - Fix a type annotation by [@brettcannon](https://github.com/brettcannon) in [#907](pypa/packaging#907) - Fix tags return type in `parse_wheel_filename` docs by [@ncoghlan](https://github.com/ncoghlan) in [#973](pypa/packaging#973) - Add type hint for `_version` in `.version.Version` by [@brettcannon](https://github.com/brettcannon) in [#927](pypa/packaging#927) - Changed static type annotations in prereleases setter method in `specifier.py` by [@subhajitsaha01](https://github.com/subhajitsaha01) in [#930](pypa/packaging#930) - Statically type the tests by [@henryiii](https://github.com/henryiii) in [#982](pypa/packaging#982) Internal: - Test and declare support Python 3.14 by [@henryiii](https://github.com/henryiii) in [#901](pypa/packaging#901) - Modernize and speed up tests on Python 3.14 by [@henryiii](https://github.com/henryiii) in [#903](pypa/packaging#903) - Change our license metadata to use an SPDX license expression by [@cdce8p](https://github.com/cdce8p) in [#881](pypa/packaging#881) - No need for `license-files` by [@DimitriPapadopoulos](https://github.com/DimitriPapadopoulos) in [#924](pypa/packaging#924) - Update mypy by [@hauntsaninja](https://github.com/hauntsaninja) in [#891](pypa/packaging#891) - 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Update changelog with recent additions by [@henryiii](https://github.com/henryiii) in [#1034](pypa/packaging#1034) - Publish to PyPI via GitHub CI by [@EpicWink](https://github.com/EpicWink) in [#893](pypa/packaging#893) - Use prek for faster pre-commit lint step by [@henryiii](https://github.com/henryiii) in [#1037](pypa/packaging#1037) - Add help text to noxfile by [@henryiii](https://github.com/henryiii) in [#1038](pypa/packaging#1038) - Update licenses to 3.27 by [@henryiii](https://github.com/henryiii) in [#1036](pypa/packaging#1036) - Use relative import in `packaging.licenses` by [@notatallshaw](https://github.com/notatallshaw) in [#1039](pypa/packaging#1039) - Add zizmor and tighten up CI by [@henryiii](https://github.com/henryiii) in [#1035](pypa/packaging#1035) - Fix release script by [@henryiii](https://github.com/henryiii) in [#1040](pypa/packaging#1040) - Fix using a dev version (again) by [@henryiii](https://github.com/henryiii) in [#1041](pypa/packaging#1041) - Fix type hint of function used with `contextlib.contextmanager` by [@SpecLad](https://github.com/SpecLad) in [#1046](pypa/packaging#1046) - Always run tests by [@henryiii](https://github.com/henryiii) in [#1044](pypa/packaging#1044) - Fix a changelog number by [@henryiii](https://github.com/henryiii) in [#1042](pypa/packaging#1042) - Fix the publish job by [@henryiii](https://github.com/henryiii) in [#1043](pypa/packaging#1043) - Get the correct tag on publish by [@henryiii](https://github.com/henryiii) in [#1045](pypa/packaging#1045) - Test on first public release of CPython 3.11 and newer by [@henryiii](https://github.com/henryiii) in [#1056](pypa/packaging#1056) - Fix publication job (again) by [@henryiii](https://github.com/henryiii) in [#1051](pypa/packaging#1051) - Use `actionlint` to check CI workflows by [@miketheman](https://github.com/miketheman) in [#1052](pypa/packaging#1052) - Fix formatting of distribution types in metadata.rst by [@brettcannon](https://github.com/brettcannon) in [#1053](pypa/packaging#1053) #### New Contributors - [@cdce8p](https://github.com/cdce8p) made their first contribution in [#881](pypa/packaging#881) - [@dholth](https://github.com/dholth) made their first contribution in [#860](pypa/packaging#860) - [@trim21](https://github.com/trim21) made their first contribution in [#908](pypa/packaging#908) - [@yarikoptic](https://github.com/yarikoptic) made their first contribution in [#910](pypa/packaging#910) - [@cthoyt](https://github.com/cthoyt) made their first contribution in [#868](pypa/packaging#868) - [@bwoodsend](https://github.com/bwoodsend) made their first contribution in [#879](pypa/packaging#879) - [@stefan6419846](https://github.com/stefan6419846) made their first contribution in [#921](pypa/packaging#921) - [@bearomorphism](https://github.com/bearomorphism) made their first contribution in [#913](pypa/packaging#913) - [@EpicWink](https://github.com/EpicWink) made their first contribution in [#922](pypa/packaging#922) - [@Liam-DeVoe](https://github.com/Liam-DeVoe) made their first contribution in [#932](pypa/packaging#932) - [@subhajitsaha01](https://github.com/subhajitsaha01) made their first contribution in [#930](pypa/packaging#930) - 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brettcannon added 9 commits June 5, 2025 10:37

Implement PEP 794

937a2c7

Add Import-Namespace

a5b1bca

Add Import-Namespace and ; private

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Merge branch 'pep-794' of https://github.com/brettcannon/packaging in…

63a0c66

…to pep-794

Merge fixes

4de9765

Fix some duplicate key entries

ed1a56d

Final merge fixes

5b571b9

Update external references in metadata.py

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Merge branch 'main' into pep-794

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brettcannon commented Oct 20, 2025

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brettcannon added 2 commits October 20, 2025 12:02

Fix formatting

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Update expected metadata version in test to 2.5

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This was referenced Oct 20, 2025

feat: PEP 794 support abravalheri/validate-pyproject#271

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feat: PEP 794 support (METADATA 2.5) pypa/pyproject-metadata#260

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Merge branch 'main' into pep-794

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henryiii reviewed Oct 24, 2025

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Bump the core metadata version for everything.metdata

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brettcannon and others added 3 commits October 24, 2025 10:19

Update metadata_version assertion to 2.5

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Merge branch 'main' into pep-794

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fix: handle special case when import-names is empty

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Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

brettcannon merged commit e83801f into pypa:main Oct 24, 2025
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henryiii mentioned this pull request Oct 25, 2025

pyproject: support for PEP 794 SchemaStore/schemastore#5077

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radoering mentioned this pull request Nov 19, 2025

Support import-names according to PEP-794 python-poetry/poetry-core#894

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Bump packaging from 25.0 to 26.0 senzing-factory/dockerhub-util#176

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Implement PEP 794 (Import Name Metadata)#948

Implement PEP 794 (Import Name Metadata)#948
brettcannon merged 16 commits intopypa:mainfrom
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