search

matklad / once_cell

Rust library for single assignment cells and lazy statics without macros
Apache License 2.0
1.84k stars 110 forks source link

Minimum Rust Version #201

Closed mitsuhiko closed 1 year ago

mitsuhiko commented 2 years ago

The latest version of once_cell bumps up the minimum requirement up to 1.56 which is a huge jump. Is it conceivable to do a major version bump for this so that people who want to depend on it for libraries that wan to support older versions can stay on the old version?

matklad commented 1 year ago

I'd rather keep https://github.com/matklad/once_cell/blob/master/Cargo.toml#L7 as a source of truth.

kornelski commented 1 year ago

I'll drop my regular reminder that I'm gathering stats for ecosystem-wide MSRV here: https://lib.rs/stats#rustc

The current state is that MSRV < 1.56 is a waste of time.

The latest edition, just like the previous one, is a major cliff. Already over a quarter of all crates have upgraded to edition 2021 (or equally new features). Those crates haven't upgraded yet are mainly dead unmaintained ones. Out of actively maintained crates, a whooping 80% require 1.56+.

I don't think it's reasonably possible any more to develop a non-toy project that uses both up-to-date dependencies and Rust < 1.56. If you're spending effort on supporting old MSRV you're in the minority, and putting this all effort for an even smaller minority.

MSRV has an incredibly "viral" negative network effect. The worst-MSRV-wins effect means that even if 99% of your dependencies try to support old Rust, and 1% doesn't, then your project and everyone using is still 100% broken.

matklad commented 1 year ago

I think the discussion has run its course here, closing!

I've clarified the exact supported range in https://github.com/matklad/once_cell/pull/204, but otherwise the policy articulated in the first comment remains unchanged!