[Pkg-rust-maintainers] Bug#1124769: rustc: FTBFS rustc in Debian Bookworm because of conflict in build deps

[Sergei Semin]

Fabian, hi!

Thank you for such quick answer!

You wrote:

> that sounds like your repository setup is incomplete? did you maybe
forget to also add the corresponding main bookworm repository?

I think my repository setup is complete. As proof that main bookworm
repository added in my setup:
```
root at 9925b7386ff9:/# apt policy rustc
rustc:
  Installed: (none)
  Candidate: 1.63.0+dfsg1-2
  Version table:
     1.63.0+dfsg1-2 500
        500 http://deb.debian.org/debian bookworm/main arm64 Packages
root at 9925b7386ff9:/#
```

So, I can install binary rustc package. Binary rustc package is located
in main bookworm repository. So I think it's all ok with my repository
setup.

You wrote:

> because I cannot reproduce this at all

Do you tried all steps exactly as I described in first message in this
thread? I used only base tools like apt and nano (no advanced
complicated tools like sbuild), so, I think, there can be no mistakes
in described steps sequence to reproduce problem in Debian Bookworm
environment.
I use official Debian Bookworm image from these resource:
https://hub.docker.com/layers/library/debian/bookworm/images/sha256-409529ea1ed9728a9a5fb4960fdf9163e8b608c34db681a1273c617c056d325d

I event tried to pull image again, but it is up to date:
```

ubuntu at ubuntu:~$ sudo docker run --pull=always -it --rm debian:bookworm
bash
bookworm: Pulling from library/debian
Digest:
sha256:c66c66fac809bfb56a8001b12f08181a49b6db832d2c8ddabe22b6374264055f
Status: Image is up to date for debian:bookworm
root at 7c98c710cd67:/#
```

I tried again steps described at beginning of this thread with new
fresh container. Even I removed local apt lists before final apt
update. Please look at repository configuration and output of `apt
update`:
```
root at 7c98c710cd67:/# rm -rf /var/lib/apt/lists/*
root at 7c98c710cd67:/# cat /etc/apt/sources.list.d/debian.sources
Types: deb deb-src
# http://snapshot.debian.org/archive/debian/20251229T000000Z
URIs: http://deb.debian.org/debian
Suites: bookworm bookworm-updates
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg

Types: deb deb-src
# http://snapshot.debian.org/archive/debian-security/20251229T000000Z
URIs: http://deb.debian.org/debian-security
Suites: bookworm-security
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg
root at 7c98c710cd67:/# apt update
Get:1 http://deb.debian.org/debian bookworm InRelease [151 kB]
Get:2 http://deb.debian.org/debian bookworm-updates InRelease [55.4 kB]
Get:3 http://deb.debian.org/debian-security bookworm-security InRelease
[48.0 kB]
Get:4 http://deb.debian.org/debian bookworm/main Sources [9494 kB]
Get:5 http://deb.debian.org/debian bookworm/main arm64 Packages [8693
kB]
Get:6 http://deb.debian.org/debian bookworm-updates/main Sources [3288
B]                                                                    
Get:7 http://deb.debian.org/debian bookworm-updates/main arm64 Packages
[6936 B]                                                              
Get:8 http://deb.debian.org/debian-security bookworm-security/main
Sources [196 kB]                                                      
Get:9 http://deb.debian.org/debian-security bookworm-security/main
arm64 Packages [286 kB]                                               
Fetched 18.9 MB in 15s (1260 kB/s)                                    
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
root at 7c98c710cd67:/#
```

I think it's all ok with main bookworm repository in this setup. Do you
agree?

And problem is still here:
```
root at 7c98c710cd67:/# apt -s build-dep rustc
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libstd-rust-web-dev : Conflicts: libstd-rust-dev
 rustc-web : Conflicts: rustc
E: Error, pkgProblemResolver::Resolve generated breaks, this may be
caused by held packages.
root at 7c98c710cd67:/#
```

Described problem can be reproduced with described steps in Debian
Bookworm amd64 environment, I checked again.

And last info. I tried to reproduce described problem in Debian Trixie
docker image (arm64):
```
ubuntu at ubuntu:~$ sudo docker run --pull=always --rm -it debian:trixie
bash
trixie: Pulling from library/debian
5785abec2864: Pull complete 
Digest:
sha256:c71b05eac0b20adb4cdcc9f7b052227efd7da381ad10bb92f972e8eae7c6cdc9
Status: Downloaded newer image for debian:trixie
root at eae19363f5e9:/#
```

And it's all ok in Debian Trixie. `apt -s build-dep rustc` successfully
works. In amd64 too. So, I think, that way to reproduce problem in
Debian Bookworm is correct, but some problem in build deps of rustc in
Debian Bookworm exists (at least in amd64, arm64 - maybe in other archs
too).