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Reject invalid classifiers, warn on license classifiers#18419

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ww/warn-license-classifier
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Reject invalid classifiers, warn on license classifiers#18419
woodruffw merged 3 commits intomainfrom
ww/warn-license-classifier

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@woodruffw woodruffw commented Mar 12, 2026 •
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Summary

This makes two changes to our handling of trove classifiers in uv's build backend:

  1. We now reject malformed trove classifiers. I've done this by adding a Classifier newtype that parses and rejects anything that looks wrong (there's no formal grammar for classifiers, so this is a pretty primitive check, but it should be enough to preempt most common user errors). We don't use an allowlist at the moment, although in principle we could do that as well/instead.
  2. We now emit a user warning on any license classifiers, since these have been deprecated since PEP 639 was accepted. I've added this within PyProjectToml::license_metadata since in the future we'll also want to produce a hard error when license classifiers are present and new-style structured license metadata is also present. That change will require a breaking release however.

Closes #16354.

Test Plan

I've added some new unit tests for this, plus an integration test for the user warning.

@woodruffw
Reject invalid classifiers, warn on license classifiers
de7cd8c 
Signed-off-by: William Woodruff <william@astral.sh>
@woodruffw woodruffw requested a review from konstin March 12, 2026 14:50
@woodruffw woodruffw self-assigned this Mar 12, 2026
woodruffw
woodruffw commented Mar 12, 2026
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crates/uv-build-backend/src/metadata.rs
Comment on lines +920 to +924
// A classifier has two or more non-empty parts separated by ` :: `.
let mut parts = s.split(" :: ");
let valid = parts.next().is_some_and(|p| !p.is_empty())
&& parts.next().is_some_and(|p| !p.is_empty())
&& parts.all(|p| !p.is_empty());
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Flagging: I wrote it this way because I'm allergic to intermediate allocations, and the most "obvious" form would involve one (via Vec<&str>). Happy to change though if this seems like a silly micro-optimization 🙂

@woodruffw
Add an integration test
2b0a68c 
Signed-off-by: William Woodruff <william@astral.sh>
@woodruffw woodruffw requested a review from zsol March 12, 2026 15:03
@woodruffw
Add some testcases
a9668e4 
Signed-off-by: William Woodruff <william@astral.sh>
@woodruffw woodruffw mentioned this pull request Mar 12, 2026
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@woodruffw woodruffw marked this pull request as ready for review March 12, 2026 15:34
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konstin commented Mar 13, 2026 •
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There's some risk we break uv_build for existing packages, is there a way to check whether the classifiers in the wild (or their subset for uv_build projects) are valid? The risk is that this transitively affects packages that depend on the source dist of the package with the invalid classifier.

Code looks good otherwise.

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woodruffw commented Mar 13, 2026

is there a way to check whether the classifiers in the wild (or their subset for uv_build projects) are valid?

I could probably do a batch scan of PyPI, although I think PyPI has also validated classifiers on upload for a very long time so I wouldn't expect anything in the last 7+ years to have an invalid classifier in its metadata.

Still, I agree it's a risk. Do you think it makes sense to start with a warning here instead and then ratchet down in the next breaking release?

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konstin commented Mar 13, 2026

I could probably do a batch scan of PyPI, although I think PyPI has also validated classifiers on upload for a very long time so I wouldn't expect anything in the last 7+ years to have an invalid classifier in its metadata.

That's perfect then!

@woodruffw woodruffw merged commit e979ed7 into main Mar 13, 2026
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@woodruffw woodruffw deleted the ww/warn-license-classifier branch March 13, 2026 13:56
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tmeijn pushed a commit to tmeijn/dotfiles that referenced this pull request Apr 2, 2026
build(deps): update uv to v0.11.3
bdac621 
This MR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [uv](https://github.com/astral-sh/uv) | minor | `0.10.9` → `0.11.3` |

MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot).

**Proposed changes to behavior should be submitted there as MRs.**

---

### Release Notes

<details>
<summary>astral-sh/uv (uv)</summary>

### [`v0.11.3`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#0113)

[Compare Source](astral-sh/uv@0.11.2...0.11.3)

Released on 2026-04-01.

##### Enhancements

- Add progress bar for hashing phase in uv publish ([#&#8203;18752](astral-sh/uv#18752))
- Add support for ROCm 7.2 ([#&#8203;18730](astral-sh/uv#18730))
- Emit abi3t tags for every abi3 version ([#&#8203;18777](astral-sh/uv#18777))
- Expand `uv workspace metadata` with dependency information from the lock ([#&#8203;18356](astral-sh/uv#18356))
- Implement support for PEP 803 ([#&#8203;18767](astral-sh/uv#18767))
- Pretty-print platform in built wheel errors ([#&#8203;18738](astral-sh/uv#18738))
- Publish installers to `/installers/uv/latest` on the mirror ([#&#8203;18725](astral-sh/uv#18725))
- Show free-threaded Python in built-wheel errors ([#&#8203;18740](astral-sh/uv#18740))

##### Preview features

- Add `--ignore` and `--ignore-until-fixed` to `uv audit` ([#&#8203;18737](astral-sh/uv#18737))

##### Bug fixes

- Bump simple API cache ([#&#8203;18797](astral-sh/uv#18797))
- Don't drop `blake2b` hashes ([#&#8203;18794](astral-sh/uv#18794))
- Handle broken range request implementations ([#&#8203;18780](astral-sh/uv#18780))
- Remove `powerpc64-unknown-linux-gnu` from release build targets ([#&#8203;18800](astral-sh/uv#18800))
- Respect dependency metadata overrides in `uv pip check` ([#&#8203;18742](astral-sh/uv#18742))
- Support debug CPython ABI tags in environment compatibility ([#&#8203;18739](astral-sh/uv#18739))

##### Documentation

- Document `false` opt-out for `exclude-newer-package` ([#&#8203;18768](astral-sh/uv#18768), [#&#8203;18803](astral-sh/uv#18803))

### [`v0.11.2`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#0112)

[Compare Source](astral-sh/uv@0.11.1...0.11.2)

Released on 2026-03-26.

##### Enhancements

- Add a dedicated Windows PE editing error ([#&#8203;18710](astral-sh/uv#18710))
- Make `uv self update` fetch the manifest from the mirror first ([#&#8203;18679](astral-sh/uv#18679))
- Use uv reqwest client for self update ([#&#8203;17982](astral-sh/uv#17982))
- Show `uv self update` success and failure messages with `--quiet` ([#&#8203;18645](astral-sh/uv#18645))

##### Preview features

- Evaluate extras and groups when determining auditable packages ([#&#8203;18511](astral-sh/uv#18511))

##### Bug fixes

- Skip redundant project configuration parsing for `uv run` ([#&#8203;17890](astral-sh/uv#17890))

### [`v0.11.1`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#0111)

[Compare Source](astral-sh/uv@0.11.0...0.11.1)

Released on 2026-03-24.

##### Bug fixes

- Add missing hash verification for `riscv64gc-unknown-linux-musl` ([#&#8203;18686](astral-sh/uv#18686))
- Fallback to direct download when direct URL streaming is unsupported ([#&#8203;18688](astral-sh/uv#18688))
- Revert treating 'Dynamic' values as case-insensitive ([#&#8203;18692](astral-sh/uv#18692))
- Remove torchdata from list of packages to source from the PyTorch index ([#&#8203;18703](astral-sh/uv#18703))
- Special-case `==` Python version request ranges ([#&#8203;9697](astral-sh/uv#9697))

##### Documentation

- Cover `--python <dir>` in "Using arbitrary Python environments" ([#&#8203;6457](astral-sh/uv#6457))
- Fix version annotations for `PS_MODULE_PATH` and `UV_WORKING_DIR` ([#&#8203;18691](astral-sh/uv#18691))

### [`v0.11.0`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#0110)

[Compare Source](astral-sh/uv@0.10.12...0.11.0)

Released on 2026-03-23.

##### Breaking changes

This release includes changes to the networking stack used by uv. While we think that breakage will be rare, it is possible that these changes will result in the rejection of certificates previously trusted by uv so we have marked the change as breaking out of an abundance of caution.

The changes are largely driven by the upgrade of reqwest, which powers uv's HTTP clients, to [v0.13](https://seanmonstar.com/blog/reqwest-v013-rustls-default/) which included some breaking changes to TLS certificate verification.

The following changes are included:

- [`rustls-platform-verifier`](https://github.com/rustls/rustls-platform-verifier) is used instead of [`rustls-native-certs`](https://github.com/rustls/rustls-native-certs) and [`webpki`](https://github.com/rustls/webpki) for certificate verification

  **This change should have no effect unless you are using the `native-tls` option to enable reading system certificates.**

  `rustls-platform-verifier` delegates to the system for certificate validation (e.g., `Security.framework` on macOS) instead of eagerly loading certificates from the system and verifying them via `webpki`. The effects of this change will vary based on the operating system. In general, uv's certificate validation should now be more consistent with browsers and other native applications. However, this is the most likely cause of breaking changes in this release. Some previously failing certificate chains may succeed, and some previously accepted certificate chains may fail. In either case, we expect the validation to be more correct and welcome reports of regressions.

  In particular, because more responsibility for validating the certificate is transferred to your system's security library, some features like [CA constraints](https://support.apple.com/en-us/103255) or [revocation of certificates](https://en.wikipedia.org/wiki/Certificate_revocation) via OCSP and CRLs may now be used.

  This change should improve performance when using system certificate on macOS, as uv no longer needs to load all certificates from the keychain at startup.
- [`aws-lc`](https://github.com/aws/aws-lc) is used instead of `ring` for a cryptography backend

  There should not be breaking changes from this change. We expect this to expand support for certificate signature algorithms.
- `--native-tls` is deprecated in favor of a new `--system-certs` flag

  The `--native-tls` flag is still usable and has identical behavior to `--system-certs.`

  This change was made to reduce confusion about the TLS implementation uv uses. uv always uses `rustls` not `native-tls`.
- Building uv on x86-64 and i686 Windows requires NASM

  NASM is required by `aws-lc`. If not found on the system, a prebuilt blob provided by `aws-lc-sys` will be used.

  If you are not building uv from source, this change has no effect.

  See the [CONTRIBUTING](https://github.com/astral-sh/uv/blob/b6854d77bfd0cb78157fecaf8b30126c6f16bc11/CONTRIBUTING.md#setup) guide for details.
- Empty `SSL_CERT_FILE` values are ignored (for consistency with `SSL_CERT_DIR`)

See [#&#8203;18550](astral-sh/uv#18550) for details.

##### Python

- Enable frame pointers for improved profiling on Linux x86-64 and aarch64

See the [python-build-standalone release notes](https://github.com/astral-sh/python-build-standalone/releases/20260320) for details.

##### Enhancements

- Treat 'Dynamic' values as case-insensitive ([#&#8203;18669](astral-sh/uv#18669))
- Use a dedicated error for invalid cache control headers ([#&#8203;18657](astral-sh/uv#18657))
- Enable checksum verification in the generated installer script ([#&#8203;18625](astral-sh/uv#18625))

##### Preview features

- Add `--service-format` and `--service-url` to `uv audit` ([#&#8203;18571](astral-sh/uv#18571))

##### Performance

- Avoid holding flat index lock across indexes ([#&#8203;18659](astral-sh/uv#18659))

##### Bug fixes

- Find the dynamic linker on the file system when sniffing binaries fails ([#&#8203;18457](astral-sh/uv#18457))
- Fix export of conflicting workspace members with dependencies ([#&#8203;18666](astral-sh/uv#18666))
- Respect installed settings in `uv tool list --outdated` ([#&#8203;18586](astral-sh/uv#18586))
- Treat paths originating as PEP 508 URLs which contain expanded variables as relative ([#&#8203;18680](astral-sh/uv#18680))
- Fix `uv export` for workspace member packages with conflicts ([#&#8203;18635](astral-sh/uv#18635))
- Continue to alternative authentication providers when the pyx store has no token ([#&#8203;18425](astral-sh/uv#18425))
- Use redacted URLs for log messages in cached client ([#&#8203;18599](astral-sh/uv#18599))

##### Documentation

- Add details on Linux versions to the platform policy ([#&#8203;18574](astral-sh/uv#18574))
- Clarify `FLASH_ATTENTION_SKIP_CUDA_BUILD` guidance for `flash-attn` installs ([#&#8203;18473](astral-sh/uv#18473))
- Split the dependency bots page into two separate pages ([#&#8203;18597](astral-sh/uv#18597))
- Split the alternative indexes page into separate pages ([#&#8203;18607](astral-sh/uv#18607))

### [`v0.10.12`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#01012)

[Compare Source](astral-sh/uv@0.10.11...0.10.12)

Released on 2026-03-19.

##### Python

- Add pypy 3.11.15 ([#&#8203;18468](astral-sh/uv#18468))
- Add support for using Python 3.6 interpreters ([#&#8203;18454](astral-sh/uv#18454))

##### Enhancements

- Include uv's target triple in version report ([#&#8203;18520](astral-sh/uv#18520))
- Allow comma separated values in `--no-emit-package` ([#&#8203;18565](astral-sh/uv#18565))

##### Preview features

- Show `uv audit` in the CLI help ([#&#8203;18540](astral-sh/uv#18540))

##### Bug fixes

- Improve reporting of managed interpreter symlinks in `uv python list` ([#&#8203;18459](astral-sh/uv#18459))
- Preserve end-of-line comments on previous entries when removing dependencies ([#&#8203;18557](astral-sh/uv#18557))
- Treat abi3 wheel Python version as a lower bound ([#&#8203;18536](astral-sh/uv#18536))
- Detect hard-float support on aarch64 kernels running armv7 userspace ([#&#8203;18530](astral-sh/uv#18530))

##### Documentation

- Add Python 3.15 to supported versions ([#&#8203;18552](astral-sh/uv#18552))
- Adjust the PyPy note ([#&#8203;18548](astral-sh/uv#18548))
- Move Pyodide to Tier 2 in the Python support policy ([#&#8203;18561](astral-sh/uv#18561))
- Move Rust and Python version support out of the Platform support policy ([#&#8203;18535](astral-sh/uv#18535))
- Update Docker guide with changes from `uv-docker-example` ([#&#8203;18558](astral-sh/uv#18558))
- Update the Python version policy ([#&#8203;18559](astral-sh/uv#18559))

### [`v0.10.11`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#01011)

[Compare Source](astral-sh/uv@0.10.10...0.10.11)

Released on 2026-03-16.

##### Enhancements

- Fetch Ruff release metadata from an Astral mirror ([#&#8203;18358](astral-sh/uv#18358))
- Use PEP 639 license metadata for uv itself ([#&#8203;16477](astral-sh/uv#16477))

##### Performance

- Improve distribution id performance ([#&#8203;18486](astral-sh/uv#18486))

##### Bug fixes

- Allow `--project` to refer to a `pyproject.toml` directly and reduce to a warning on other files ([#&#8203;18513](astral-sh/uv#18513))
- Disable `SYSTEM_VERSION_COMPAT` when querying interpreters on macOS ([#&#8203;18452](astral-sh/uv#18452))
- Enforce available distributions for supported environments ([#&#8203;18451](astral-sh/uv#18451))
- Fix `uv sync --active` recreating active environments when `UV_PYTHON_INSTALL_DIR` is relative ([#&#8203;18398](astral-sh/uv#18398))

##### Documentation

- Add missing `-o requirements.txt` in `uv pip compile` example ([#&#8203;12308](astral-sh/uv#12308))
- Link to organization security policy ([#&#8203;18449](astral-sh/uv#18449))
- Link to the AI policy in the contributing guide ([#&#8203;18448](astral-sh/uv#18448))

### [`v0.10.10`](https://github.com/astral-sh/uv/blob/HEAD/CHANGELOG.md#01010)

[Compare Source](astral-sh/uv@0.10.9...0.10.10)

Released on 2026-03-13.

##### Python

- Add CPython 3.15.0a7 ([#&#8203;18403](astral-sh/uv#18403))

##### Enhancements

- Add `--outdated` flag to `uv tool list` ([#&#8203;18318](astral-sh/uv#18318))
- Add riscv64 musl target to build-release-binaries workflow ([#&#8203;18228](astral-sh/uv#18228))
- Fetch Ruff from an Astral mirror ([#&#8203;18286](astral-sh/uv#18286))
- Improve error handling for platform detection in Python downloads ([#&#8203;18453](astral-sh/uv#18453))
- Warn if `--project` directory does not exist ([#&#8203;17714](astral-sh/uv#17714))
- Warn when workspace member scripts are skipped due to missing build system ([#&#8203;18389](astral-sh/uv#18389))
- Update build backend versions used in `uv init` ([#&#8203;18417](astral-sh/uv#18417))
- Log explicit config file path in verbose output ([#&#8203;18353](astral-sh/uv#18353))
- Make `uv cache clear` an alias of `uv cache clean` ([#&#8203;18420](astral-sh/uv#18420))
- Reject invalid classifiers, warn on license classifiers in `uv_build` ([#&#8203;18419](astral-sh/uv#18419))

##### Preview features

- Add links to `uv audit` output ([#&#8203;18392](astral-sh/uv#18392))
- Output/report formatting for `uv audit` ([#&#8203;18193](astral-sh/uv#18193))
- Switch to batched OSV queries for `uv audit` ([#&#8203;18394](astral-sh/uv#18394))

##### Bug fixes

- Avoid sharing version metadata across indexes ([#&#8203;18373](astral-sh/uv#18373))
- Bump zlib-rs to 0.6.2 to fix panic on decompression of large wheels on Windows ([#&#8203;18362](astral-sh/uv#18362))
- Filter out unsupported environment wheels ([#&#8203;18445](astral-sh/uv#18445))
- Preserve absolute/relative paths in lockfiles ([#&#8203;18176](astral-sh/uv#18176))
- Recreate Python environments under `uv tool install --force` ([#&#8203;18399](astral-sh/uv#18399))
- Respect timestamp and other cache keys in cached environments ([#&#8203;18396](astral-sh/uv#18396))
- Simplify selected extra markers in `uv export` ([#&#8203;18433](astral-sh/uv#18433))
- Send pyx mint-token requests with a proper `Content-Type` ([#&#8203;18334](astral-sh/uv#18334))
- Fix Windows operating system and version reporting ([#&#8203;18383](astral-sh/uv#18383))

##### Documentation

- Update the platform support policy with a tier 3 section including freebsd and 32-bit windows ([#&#8203;18345](astral-sh/uv#18345))

</details>

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[uv_build] Emit warning when both license (PEP639) and legacy license classifiers are present in pyproject.toml

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