[Pkg-rust-maintainers] Bug#1126584: rustc: build stage0 orig tarball from Debian builds

[Emilio Pozuelo Monfort]

Package: rustc
Version: 1.91.1+dfsg1-1
Severity: normal

Hi,

rustc includes a script, debian/make_orig-stage0_tarball.sh, to create a
stage0.orig.tar.xz that can be used to bootstrap rustc. I don't think that's
used much, since new updates in Debian sid will use X-1 from sid to build.
However, when uploading a (much newer) version to (old)stable, we don't have
X-1, so we need to create and use a -stage0 tarball.

The issue I find is that upstream doesn't support some of our release
architectures, so when doing these backports, we lack a way to bootstrap the
new version on those architectures. See for example [1].

One possibility would be to create the -stage0 tarballs using Debian sid packages
for X-1. I haven't looked in detail, but perhaps we would need statically linked
binaries, which could be done in an extra build and placed in a rust-static .deb.
Then make_orig-stage0_tarball could look for those .debs from snapshot.debian.org.

Thoughts?

Cheers,
Emilio

[1] https://buildd.debian.org/status/fetch.php?pkg=rustc-web&arch=mipsel&ver=1.85.0%2Bdfsg3-1%7Edeb12u3&stamp=1754252552&raw=0