[Pkg-rust-maintainers] chromium and rustc in bookworm

[Adrian Bunk]

On Sun, Jan 21, 2024 at 06:55:31PM -0500, Andres Salomon wrote:
>...
> b) Backport the profiler patch to bookworm's rustc, and do a s-p-u update to
> Bookworm's rustc. Since this adds a new feature, I don't view it as too
> risky, but the release team or rust team may feel differently. The main
> downsides to this are the potential for breaking existing packages in
> stable, and the fact that Chromium will undoubtedly begin to rely on newer
> Rust language features (as they do with Clang) which may not work on
> bookworm's 1.63.0. Once that happens, we'll be right back here.
> 
> c) Much like the Firefox maintainer(s) created rustc-mozilla for
> (old)oldstable, we create a 'rustc-chromium' package for bookworm. It could
> even be used for Firefox if their ESR updates start needing newer Rust
> language features (in which case, maybe 'rustc-newer' or 'rustc-browsers' is
> a better name for it? Or like Clang, include the major version and call it
> 'rustc-1.70').
> 
> 
> As I'm still messing around with bookworm's rustc(+profiler) as well as
> trying to get Chromium 121.x to build in Sid, I don't have a strong opinion
> on this yet. However, I wanted to bring it to everyone's attention, and see
> if anyone else did have strong opinions either way. If one of the teams
> feels strongly against option (b) for example, I won't bother continuing to
> work on that option.

IMHO c) would be best, with one rustc-* package shared for both browsers.

AFAIK rustc 1.78 (to be released in May) will be required by the next 
Firefox ESR 128, and bookworm will switch to 128 in September/October.

The annual rustc upgrade for Firefox in *stable does also require an 
annual addition of a new LLVM version in *stable.

Short-term a version of the bookworm rustc with the profiler patch you 
need could then be uploaded as a first version of this rustc-browsers
(or however it is named) package.

The critical question is whether the annual LLVM+rustc upgrade cadence 
for Firefox in stable is compatible with what Chromium needs.

> Thanks,
> Andres

cu
Adrian

BTW:
I am not personally involved in any of the mentioned packages, just 
pointing out what seems to be the least work while avoiding even more
rustc and LLVM versions in stable releases.