ci: add required-features entries to Cargo.toml

[davidhewitt]

This is a bit of an experiment to skip building tests when the feature combinations being run (typically --no-default-features) don't satisfy the cfgs at the top of the test files.

We have historically just made these test bodies empty with a #![cfg(feature = "...")] directive at the top of test files. I think these are good for clarity purposes; they're close to the code and can easily be updated if things change.

By adding these tests to required-features in Cargo.toml we can avoid producing useless test binaries. I would prefer to keep the cfg clauses around, so I wrote a nox job to lint that the cfgs match the Cargo.toml.

Open to opinions whether this is too much, and I should just drop this patch or remove the cfg markers.

[davidhewitt]

This looks like it had some noticeable improvement to macos jobs (maybe ~2 mins), a small effect on windows jobs (maybe ~30s), and no noticeable effect on ubuntu jobs.

Could be due to different filesystem / kernel characteristics, I suppose?

I think given that there are some small wins and the test output is a fair bit cleaner with this (no "ran 0 tests" lines), I'm inclined to merge this, what do others think?

[bschoenmaeckers]

LGTM!

[alex]

Makes sense to me All that is necessary for evil to succeed is for good people to do nothing.

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On Mon, May 11, 2026, 7:09 AM David Hewitt ***@***.***> wrote: *davidhewitt* left a comment (PyO3/pyo3#6031) <#6031 (comment)> This looks like it had some noticeable improvement to macos jobs (maybe ~2 mins), a small effect on windows jobs (maybe ~30s), and no noticeable effect on ubuntu jobs. Could be due to different filesystem / kernel characteristics, I suppose? I think given that there are some small wins and the test output is a fair bit cleaner with this (no "ran 0 tests" lines), I'm inclined to merge this, what do others think? — Reply to this email directly, view it on GitHub <#6031 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAAGBB4ZBMRO3NKRD7OIIT42GYF7AVCNFSM6AAAAACYY3V5SKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DIMRQGEYDIOBYGA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>