getrandom 0.3.4 has MSRV 1.63 but FreeBSD < 12 support was removed only in Rust 1.75

[briansmith]

See https://doc.rust-lang.org/beta/releases.html#version-1750-2023-12-28.

In PR #416, support for FreeBSD < 12 was removed, but Rust 1.63 does support FreeBSD < 12. Thus, one could build getrandom 3.4 using the Rust 1.63 toolchain and get a FreeBSD 10 executable, but it wouldn't actually run (or link?) on FreeBSD 10.

Note that I don't actually care about this specific case. I'm just filing this to build awareness of the logic error that seems to be being regularly committed: Our MSRV is X, but we start making assumptions that are only valid for a later version of the Rust toolchain X+Y. See #812 for another example.

[josephlr]

@newpavlov can correct me if I'm wrong, but looking at https://docs.rs/getrandom/0.3.4/getrandom/#platform-support, our policy is that a point release:

1. will not require a new version of the Rust compiler
2. may drop support for platforms if the support is dropped by the most recent stable release of Rust.

So #416 doesn't contradict our documentation, although we do sometimes keep older platform support around if there's interest.

I'd be down to consider a change to policy point (2), but I'd still want to be able to drop platform support in a point-release. For example, we could have a policy like:

In stable releases, getrandom may create new patch releases that remove support for outdated platform versions. This will only be done if both:

• the platform support has been removed from the last 3 stable releases of the Rust compiler.
• the platform is End-of-Life (EOL)

So dropping FreeBSD 10/11 (under this new policy) could have been done anytime after 2024-03-21 (the release of Rust 1.77), as support was dropped in 1.75, and FreeBSD 11 went EOL on 2021-09-30.

[briansmith]

2. may drop support for platforms if the support is dropped by the most recent stable release of Rust.

OK, it seems this case has already been considered.

[newpavlov]

I concur with @josephlr.