Use NonZero in MixedUnit for C strings #15
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New bench after rebase, still regressing (on ARM):
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Seems to be a result of inlining decisions by the compiler, as sprinkling |
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Should we try to add some |
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Yes, I have something in the works... :D |
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Now uses inline, but main branch does as well (aarch64):
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And x86-64:
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Today's nightly (28f1c8079 2025-06-24) bench rerun (aarch64):
Some things to notice:
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Today's nightly (28f1c8079 2025-06-24) bench rerun (amd64):
Some things to notice:
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In conclusion it seems that the perf impact of this change is largely neutral. |
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Should we close it then? |
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Well, the main reason to do it is to give more guarantees for C strings, which cannot contain nulls. This change makes this guaranteed by the type system. So as perf looks neutral, I think we should do it. |
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Oh my bad, thought it was about performance. Then seems all good if perf are not negatively impacted. 👍 Please just fix the CI and then seems all good to me. |
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Which use cases require stable support? |
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None as far as I know but considering it's a public crate and that 1.89 will be released in less than 3 months, I suppose we can just wait? |
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Sure waiting is one options, and given 1.88 is around the corner, it should only be about 6 weeks. Possible alternatives:
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MSRV is working well nowadays with cargo as it prevents to update to a newer version if MSRV is incompatible. So raising MSRV to 1.89 once it's out seems like the best idea to me. |
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I added the MSRV, which should cause cargo to emit an error against lower versions. I would expect to see that reflected in the stable-checks CI here, but I don't... because I failed to actually push the right change. Now produces: not sure why three times... |
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@GuillaumeGomez will anyone be disadvantaged if we were to do a release with this change right now? If MSRV is well supported now, then presumably no-one is disadvantaged? |
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Well, we still need 1.89 to be released. So just 6 more weeks to wait and then we can do a release. However, we can already release the latest changes you made which improved performance if you want? |
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Make C strings safer, by encoding the absence of nulls in the type system. This is made possible by rust-lang/rust#141001 which should hit stable in 1.89.
Seems to be a big regression as written (on ARM):