Bug#1139451: trixie-pu: package llvm-toolchain-22/1:22.1.7-1~deb13u1

[Andres Salomon]

On 6/9/26 07:54, Adrian Bunk wrote:
> Control: tags -1 moreinfo
> 
> On Tue, Jun 09, 2026 at 03:20:25AM -0400, Andres Salomon wrote:
>> ...
>> [ Impact ]
>> Minimal, as this only impacts packages which intentionally choose to build
>> against llvm-toolchain-22.
>>
>> Note that this version of llvm-toolchain-$VERSION (unlike past versions)
>> builds libc++1, libc++abi1, and llvm-libunwind1 packages *without* the major
>> version in the package name. This could cause problems in future backports
>> of llvm-toolchain-$VERSION, but won't be a problem for trixie since it was
>> released with an older version of llvm-toolchain-19 that included libc++1-19
>> (and friends).
> 
> This is a problem for trixie, where these unversioned packages are built
> from src:llvm-defaults.
> 
> # apt-get install starpu-examples/trixie libomp5/sid
> ...
> The following packages have unmet dependencies:
>   libomp5 : Conflicts: libomp-x.y
>   libomp5-19 : Conflicts: libomp-x.y
> E: Unable to correct problems, you have held broken packages.
> E: The following information from --solver 3.0 may provide additional context:
>     Unable to satisfy dependencies. Reached two conflicting decisions:
>     1. libomp5-19:amd64 is selected for install because:
>        1. starpu-examples:amd64=1.4.7+dfsg-2 is selected for install
>        2. starpu-examples:amd64=1.4.7+dfsg-2 Depends libomp5-19 (>= 0.20130412)
>     2. libomp5-19:amd64 is not selected for install because:
>        1. libomp5:amd64=1:22.1.7-1 is selected for install
>        2. libomp5-19:amd64 Conflicts libomp-x.y
>           [selected libomp5:amd64=1:22.1.7-1]
> #
> 
> In practice this might mean that when both starpu-examples/trixie and
> libomp5/trixie are installed, then llvm-toolchain-22/1:22.1.7-1~deb13u1
> in trixie might result in a dist-upgrade removing starpu-examples.

Thanks! You're right, I didn't look at libomp. For right now, I think 
what I'll do is simply drop the unversioned lib packages (libc++1, 
libc++abi1, llvm-libunwind1, and libomp5) until I come up with a better 
solution. Chromium (and rust) can continue statically linking against 
the various libraries.

I'm having the -22 dev packages depend upon -19 libs. Despite having a 
stable ABI, this is not really supported; the llvm-toolchain packages 
support that kind of thing in the other direction (-22 dev packages can 
be made to depend on -23 libs). However, at least for trixie (and 
potentially bookworm, but I haven't tested it yet), this will be fine 
for rust & chromium since they're building statically against those dev 
packages. Simply dropping the library deps in those dev packages results 
in llvm build failures, as internally llvm appears to link to them 
dynamically, and I didn't feel like spending too long investigating why.

Please see the attached patch for the updated diff. I tested this by 
build chromium (statically) with it on trixie.


> 
>> ...
>> +  * Change build-dep from sid's llvm-spirv-22 to trixie's llvm-spirv-19.
>> ...
> 
> I assume that didn't run into #1128822, adding trixie to SPIRV_DISABLE_DISTRO
> would be an alternative.

I didn't hit that, no. Hopefully I don't hit it for bookworm, either!

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