Bug#1029010: llvm-toolchain-15: autopkgtest regression

[Faidon Liambotis]

On Wed, Mar 08, 2023 at 09:41:21AM +0000, Simon McVittie wrote:
> > there is a metapackage, libc++-dev-wasm32, which Depends on the
> > default implementation, which is libc++-14-dev-wasm32 right now. That
> > metapackage has at least one notable reverse B-D, firefox, using it to
> > build certain security/sandboxing features (RLBox[1], AIUI). That is to
> > say, this feature works (w/ 14) and does very useful things today. it
> > (seemingly) broke when it was ported to llvm-toolchain-15, which
> > src:firefox does not depend on directly.
> 
> If I understand correctly, that doesn't *necessarily* have to be RC for
> bookworm, because llvm-toolchain-15 is not (yet!) the default version
> of LLVM provided by the metapackage, and is only used by Mesa? But it
> would be a blocker for either moving the default forward from 14 to 15
> (as has already been done in experimental), or making Firefox use the
> non-default 15 toolchain like Mesa does, presumably to get some new
> feature or optimization that isn't in 14?

At least as I also understand it, that's right. 

I think it'd be a pity to revert this for 15 and we should aim for
feature parity between the two branches, but disabling it is, and can
remain an option as a plan B given where we are in the bookworm release
cycle. That's IMHO, with a biased view, as the wasm patches author, but
ultimately up to the maintainer (which is definitely not me ;).

I'm hopeful we can address the underlying issue quickly though, and I
propose to put a hold to this conversation for the time being and see
where we get with a proper resolution first. I just posted a patch in
the other bug report. Fingers crossed.

Faidon