`image` 0.25.9 needs MSRV 1.87 when enabling `jpeg` feature

[inflation]

Since its dependency zune-jpeg needs MSRV 1.87

Expected

Compiled under advertised MSRV, i.e., 1.85

Actual behaviour

Failed to compile under 1.85

Reproduction steps

1. cargo msrv on any crates with rust-version = 1.85 depending on image with jpeg feature

[197g]

I really don't know how to make this actionable, and rust-version is not to be read transitively.

It's unfortunate that zune-jpeg was missing the field prior to its 0.5.7 but it's not clear at all what the expected resolution is here. If we were to re-release 0.25.10 we'd probably update to a hard 0.5.7 dependency due to a bug fix. However, none of these changes would make the crate compile with prior versions. If we publish 0.25.10 with a rust-version = 1.87 then older toolchains will resolve to 0.25.9 when using the MSRV-aware resolver. That would then get you zune-jpeg=0.5.6 and that would still fail to compile. If we don't bump our rust-version in a 0.25.10 the MSRV-aware resolver will either behave the same or fail to find a solution. For resolver settings that are not MSRV-aware, we're not improving the situation either by making further releases.

So.. yes, but there's really not much to do except build automation that scans our dependencies for missing [package] rust-version fields and then progressively fixup those packages.

[etemesi254]

Is ther anything i can do on my side to make it less painful?

[etemesi254]

I think we can revert to having a lesser msrv , the only reason it was specified was to reduce unsafe in the library as most platform specific intrinsics were made safe.

[197g]

Publishing a new version of zune-jpeg and zune-core with no functional difference but a lower explicit rust-version compatibility would mitigate this. At least then MSRV-aware resolvers would pick up the right dependency. Those compatibility changes (zune-jpeg@0.5.9, zune-core@0.5.1) could again be reverted for the next release (0.5.10 and 0.5.2 respectively), there just needs to be one selectable version of those packages for 1.85 that has the right field indicated in Cargo.toml.

[197g]

@etemesi254 Also not the first time, we previously had this pop up with ravif (iirc) that also bumped their MSRV. And before 1.65 where rust-version was introduced it was much even worse. That's not too long ago, ecosystem is still figuring out how to best do this on all sides of tooling.