apt.llvm.org: libllvm22 Debian package depends on non existent libxml2 package

[shmerl]

I noticed that on a fresh Debian system which doesn't have libxml2 package installed, libllvm22 fails to be installed from apt.llvm.org repo with such error:

sudo apt install libllvm22:amd64

Solving dependencies... Error!  
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:

Unsatisfied dependencies:
 libllvm22 : Depends: libxml2 (>= 2.7.4) but it is not installable
Error: Unable to correct problems, you have held broken packages.
Error: The following information from --solver 3.0 may provide additional context:
   Unable to satisfy dependencies. Reached two conflicting decisions:
   1. libllvm22:amd64=1:22~++20250812100635+8710571aba2b-1~exp1~20250812220820.3025 is selected for install
   2. libllvm22:amd64 Depends libxml2 (>= 2.7.4)
      but none of the choices are installable:
      [no choices]

Package currently has this in dependencies:

Depends: libc6 (>= 2.38), libedit2 (>= 2.11-20080614-0), libffi8 (>= 3.4), libgcc-s1 (>= 4.3), libstdc++6 (>= 12), libxml2 (>= 2.7.4), libz3-4 (>= 4.13.3), libzstd1 (>= 1.5.5), zlib1g (>= 1:1.2.0)

However recent Debian has no libxml2 as separate package anymore (it used to have it as a metapackage, but it's now gone):

https://tracker.debian.org/pkg/libxml2

Can you please correct this.

[shmerl]

cc @sylvestre

[davidfiala]

It might be something deeper: While trixie is stable now, it appears that in the last week or two clang-21 is depending on unstable or testing debian packages now, such as libstdc++-15-dev.

For quite some time, clang21 installed via llvm.sh perfectly fine on trixie and only recently broke, as the proof-of-concept below shows.

Dockerfile.clangtest

# cat Dockerfile.clangtest | docker build --progress=plain -
FROM public.ecr.aws/docker/library/debian:trixie-slim

USER root
WORKDIR /root

RUN apt-get update && \
    apt-get dist-upgrade -y && \
    apt-get install -y curl gnupg lsb-release

ADD --checksum=sha256:70f8080fd855cb10cd79b140b8589a83f8a1f83d25b0bbf4436f55525425ac05 \
    --chmod=555 \
    https://apt.llvm.org/llvm.sh \
    /root/llvm.sh
RUN /root/llvm.sh 21 all && apt-get install -y clang-21-doc libomp-21-doc llvm-21-doc
RUN apt-get autoremove -y gcc g++
ENV PATH="/usr/lib/llvm-21/bin:$PATH"

#9 1.401 The following packages have unmet dependencies:
#9 1.401  clang-21 : Depends: libstdc++-15-dev but it is not installable
#9 1.401             Depends: libgcc-15-dev but it is not installable
#9 1.401             Depends: libobjc-15-dev but it is not installable
#9 1.401  clang-tools-21 : Depends: libxml2-16 (>= 2.14.1) but it is not installable
#9 1.401  libclang-21-dev : Depends: libstdc++-15-dev but it is not installable
#9 1.401                    Depends: libgcc-15-dev but it is not installable
#9 1.401                    Depends: libobjc-15-dev but it is not installable
#9 1.401  libclang-cpp21-dev : Depends: libstdc++-15-dev but it is not installable
#9 1.401                       Depends: libgcc-15-dev but it is not installable
#9 1.401  libllvm21 : Depends: libxml2-16 (>= 2.14.1) but it is not installable
#9 1.401  lldb-21 : Depends: liblldb-21 but it is not going to be installed
#9 1.401            Depends: libxml2-16 (>= 2.14.1) but it is not installable
#9 1.401            Depends: python3-lldb-21 but it is not going to be installed
#9 1.402 E: Unable to correct problems, you have held broken packages.
#9 1.402 E: The following information from --solver 3.0 may provide additional context:
#9 1.402    Unable to satisfy dependencies. Reached two conflicting decisions:
#9 1.402    1. libclang-21-dev:amd64=1:21.1.3~++20251015093208+bd9bc536b4ac-1~exp1~20251015093339.49 is selected for install
#9 1.402    2. libclang-21-dev:amd64 Depends libstdc++-15-dev
#9 1.402       but none of the choices are installable:
#9 1.402       [no choices]
#9 ERROR: process "/bin/sh -c /root/llvm.sh 21 all && apt-get install -y clang-21-doc libomp-21-doc llvm-21-doc" did not complete successfully: exit code: 100
------
 > [5/6] RUN /root/llvm.sh 21 all && apt-get install -y clang-21-doc libomp-21-doc llvm-21-doc:
1.401  lldb-21 : Depends: liblldb-21 but it is not going to be installed
1.401            Depends: libxml2-16 (>= 2.14.1) but it is not installable
1.401            Depends: python3-lldb-21 but it is not going to be installed

cat Dockerfile.clangtest | docker build --progress=plain - more detailed log in the expander:

Full llvm.sh execution with error

#9 [5/6] RUN /root/llvm.sh 21 all && apt-get install -y clang-21-doc libomp-21-doc llvm-21-doc
#9 0.140 + CURRENT_LLVM_STABLE=20
#9 0.140 + BASE_URL=http://apt.llvm.org
#9 0.140 + NEW_DEBIAN_DISTROS=("trixie" "unstable")
#9 0.140 + LLVM_VERSION=20
#9 0.140 + ALL=0
#9 0.140 ++ lsb_release -is
#9 0.144 + DISTRO=Debian
#9 0.144 ++ lsb_release -cs
#9 0.147 + VERSION_CODENAME=trixie
#9 0.147 ++ lsb_release -sr
#9 0.150 + VERSION=13
#9 0.150 + UBUNTU_CODENAME=
#9 0.150 + CODENAME_FROM_ARGUMENTS=
#9 0.150 + source /etc/os-release
#9 0.150 ++ PRETTY_NAME='Debian GNU/Linux 13 (trixie)'
#9 0.150 ++ NAME='Debian GNU/Linux'
#9 0.150 ++ VERSION_ID=13
#9 0.150 ++ VERSION='13 (trixie)'
#9 0.150 ++ VERSION_CODENAME=trixie
#9 0.150 ++ DEBIAN_VERSION_FULL=13.1
#9 0.150 ++ ID=debian
#9 0.150 ++ HOME_URL=https://www.debian.org/
#9 0.150 ++ SUPPORT_URL=https://www.debian.org/support
#9 0.150 ++ BUG_REPORT_URL=https://bugs.debian.org/
#9 0.150 + DISTRO=debian
#9 0.150 + is_new_debian=0
#9 0.150 + [[ debian == \d\e\b\i\a\n ]]
#9 0.150 + for new_distro in "${NEW_DEBIAN_DISTROS[@]}"
#9 0.150 + [[ trixie == \t\r\i\x\i\e ]]
#9 0.150 + is_new_debian=1
#9 0.150 + break
#9 0.150 + needed_binaries=(lsb_release wget gpg)
#9 0.150 + [[ 1 -eq 0 ]]
#9 0.150 + missing_binaries=()
#9 0.150 + using_curl=
#9 0.150 + for binary in "${needed_binaries[@]}"
#9 0.150 + command -v lsb_release
#9 0.150 + for binary in "${needed_binaries[@]}"
#9 0.150 + command -v wget
#9 0.150 + [[ wget == \w\g\e\t ]]
#9 0.150 + command -v curl
#9 0.150 + using_curl=1
#9 0.150 + continue
#9 0.150 + for binary in "${needed_binaries[@]}"
#9 0.150 + command -v gpg
#9 0.150 + [[ 0 -gt 0 ]]
#9 0.151 + case ${DISTRO} in
#9 0.151 + [[ 13 (trixie) == \u\n\s\t\a\b\l\e ]]
#9 0.151 + [[ 13 (trixie) == \t\e\s\t\i\n\g ]]
#9 0.151 + [[ trixie == \t\r\i\x\i\e ]]
#9 0.151 + CODENAME=unstable
#9 0.151 + LINKNAME=
#9 0.151 + '[' 2 -ge 1 ']'
#9 0.151 + '[' 2 '!=' - ']'
#9 0.151 + '[' 21 '!=' all ']'
#9 0.151 + LLVM_VERSION=21
#9 0.151 + OPTIND=2
#9 0.151 + '[' 2 -ge 2 ']'
#9 0.151 + '[' all == all ']'
#9 0.151 + ALL=1
#9 0.151 + OPTIND=3
#9 0.151 + getopts :hm:n: arg
#9 0.151 + [[ 0 -ne 0 ]]
#9 0.151 + declare -A LLVM_VERSION_PATTERNS
#9 0.151 + LLVM_VERSION_PATTERNS[9]=-9
#9 0.151 + LLVM_VERSION_PATTERNS[10]=-10
#9 0.151 + LLVM_VERSION_PATTERNS[11]=-11
#9 0.151 + LLVM_VERSION_PATTERNS[12]=-12
#9 0.151 + LLVM_VERSION_PATTERNS[13]=-13
#9 0.151 + LLVM_VERSION_PATTERNS[14]=-14
#9 0.151 + LLVM_VERSION_PATTERNS[15]=-15
#9 0.151 + LLVM_VERSION_PATTERNS[16]=-16
#9 0.151 + LLVM_VERSION_PATTERNS[17]=-17
#9 0.151 + LLVM_VERSION_PATTERNS[18]=-18
#9 0.151 + LLVM_VERSION_PATTERNS[19]=-19
#9 0.151 + LLVM_VERSION_PATTERNS[20]=-20
#9 0.151 + LLVM_VERSION_PATTERNS[21]=-21
#9 0.151 + LLVM_VERSION_PATTERNS[22]=
#9 0.151 + '[' '!' _ ']'
#9 0.151 + LLVM_VERSION_STRING=-21
#9 0.151 + [[ -n unstable ]]
#9 0.151 + REPO_NAME='deb http://apt.llvm.org/unstable/  llvm-toolchain-21 main'
#9 0.151 + wget -q --method=HEAD http://apt.llvm.org/unstable
#9 0.151 + curl -sSLI -XHEAD http://apt.llvm.org/unstable
#9 0.322 + [[ ! -f /etc/apt/trusted.gpg.d/apt.llvm.org.asc ]]
#9 0.322 + [[ -z 1 ]]
#9 0.323 + curl -sSL https://apt.llvm.org/llvm-snapshot.gpg.key
#9 0.323 + tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
#9 0.416 -----BEGIN PGP PUBLIC KEY BLOCK-----
#9 0.416 Version: GnuPG v1.4.12 (GNU/Linux)
#9 0.416
#9 0.416 mQINBFE9lCwBEADi0WUAApM/mgHJRU8lVkkw0CHsZNpqaQDNaHefD6Rw3S4LxNmM
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#9 0.416 zOr431/VfWq4S+VhMDhs15j9lyml0y4ok215VRFwrAREDg6UPMr7ajLmBQGau0Fc
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#9 0.416 21inIl2TbGo3Yn1JQLnA1YCoGwC34g8QZTJhElEQBN0X29ayWW6OdFx8MDvllbBV
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#9 0.416 M9udl+qW9wu+LyePbW6HX90LmkhNkkY2ZzUPRPDHZANU5btaPXc2H7edX4y4maQa
#9 0.416 xenqD0lGh9LGz/mps4HEZtCI5CY8o0uCMF3lT0XfXhuLksr7Pxv57yue8LLTItOJ
#9 0.416 d9Hmzp9G97SRYYeqU+8lyNXtU2PdrLLq7QHkzrsloG78lCpQcalHGACJzrlUWVP/
#9 0.416 fN3Ht3kAEQEAAYkCHwQYAQIACQUCUT2ULAIbDAAKCRAVz00Yr090IbhWEADbr50X
#9 0.416 OEXMIMGRLe+YMjeMX9NG4jxs0jZaWHc/WrGR+CCSUb9r6aPXeLo+45949uEfdSsB
#9 0.416 pbaEdNWxF5Vr1CSjuO5siIlgDjmT655voXo67xVpEN4HhMrxugDJfCa6z97P0+ML
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#9 0.416 5VPEgIAVhJ6RTZ26i/G+4J8neKyRs4vz+57UGwY6zI4AB1ZcWGEE3Bf+CDEDgmnP
#9 0.416 LSwbnHefK9IljT9XU98PelSryUO/5UPw7leE0akXKB4DtekToO226px1VnGp3Bov
#9 0.416 1GBGvpHvL2WizEwdk+nfk8LtrLzej+9FtIcq3uIrYnsac47Pf7p0otcFeTJTjSq3
#9 0.416 krCaoG4Hx0zGQG2ZFpHrSrZTVy6lxvIdfi0beMgY6h78p6M9eYZHQHc02DjFkQXN
#9 0.416 bXb5c6gCHESH5PXwPU4jQEE7Ib9J6sbk7ZT2Mw==
#9 0.416 =j+4q
#9 0.416 -----END PGP PUBLIC KEY BLOCK-----
#9 0.422 ++ apt-key list
#9 0.422 ++ grep -i llvm
#9 0.425 + [[ -z '' ]]
#9 0.425 + apt-key del AF4F7421
#9 0.425 /root/llvm.sh: line 199: apt-key: command not found
#9 0.425 + true
#9 0.426 + [[ trixie == \b\o\o\k\w\o\r\m ]]
#9 0.426 + [[ 1 -eq 1 ]]
#9 0.426 + SOURCES_FILE=/etc/apt/sources.list.d/http_apt_llvm_org_unstable_-trixie.sources
#9 0.426 + TEXT_TO_ADD='Types: deb
#9 0.426 Architectures: amd64 arm64
#9 0.426 Signed-By: /etc/apt/trusted.gpg.d/apt.llvm.org.asc
#9 0.426 URIs: http://apt.llvm.org/unstable/
#9 0.426 Suites: llvm-toolchain-21
#9 0.426 Components: main'
#9 0.426 + echo 'Types: deb
#9 0.426 Architectures: amd64 arm64
#9 0.426 Signed-By: /etc/apt/trusted.gpg.d/apt.llvm.org.asc
#9 0.426 URIs: http://apt.llvm.org/unstable/
#9 0.426 Suites: llvm-toolchain-21
#9 0.426 Components: main'
#9 0.426 + tee -a /etc/apt/sources.list.d/http_apt_llvm_org_unstable_-trixie.sources
#9 0.431 + apt-get update
#9 0.529 Hit:1 http://deb.debian.org/debian trixie InRelease
#9 0.534 Hit:3 http://deb.debian.org/debian trixie-updates InRelease
#9 0.560 Hit:4 http://deb.debian.org/debian-security trixie-security InRelease
#9 0.642 Get:2 https://apt.llvm.org/unstable llvm-toolchain-21 InRelease [6827 B]
#9 0.670 Get:5 https://apt.llvm.org/unstable llvm-toolchain-21/main amd64 Packages [21.8 kB]
#9 0.704 Get:6 https://apt.llvm.org/unstable llvm-toolchain-21/main arm64 Packages [21.6 kB]
#9 0.713 Fetched 50.3 kB in 0s (207 kB/s)
#9 0.713 Reading package lists...
#9 0.974 W: http://apt.llvm.org/unstable/dists/llvm-toolchain-21/InRelease: Policy will reject signature within a year, see --audit for details
#9 0.975 + PKG='clang-21 lldb-21 lld-21 clangd-21'
#9 0.975 + [[ 1 -eq 1 ]]
#9 0.975 + PKG='clang-21 lldb-21 lld-21 clangd-21 clang-tidy-21 clang-format-21 clang-tools-21 llvm-21-dev lld-21 lldb-21 llvm-21-tools libomp-21-dev libc++-21-dev libc++abi-21-dev libclang-common-21-dev libclang-21-dev libclang-cpp21-dev liblldb-21-dev libunwind-21-dev'
#9 0.975 + test 21 -gt 14
#9 0.975 + PKG='clang-21 lldb-21 lld-21 clangd-21 clang-tidy-21 clang-format-21 clang-tools-21 llvm-21-dev lld-21 lldb-21 llvm-21-tools libomp-21-dev libc++-21-dev libc++abi-21-dev libclang-common-21-dev libclang-21-dev libclang-cpp21-dev liblldb-21-dev libunwind-21-dev libclang-rt-21-dev libpolly-21-dev'
#9 0.975 + apt-get install -y clang-21 lldb-21 lld-21 clangd-21 clang-tidy-21 clang-format-21 clang-tools-21 llvm-21-dev lld-21 lldb-21 llvm-21-tools libomp-21-dev libc++-21-dev libc++abi-21-dev libclang-common-21-dev libclang-21-dev libclang-cpp21-dev liblldb-21-dev libunwind-21-dev libclang-rt-21-dev libpolly-21-dev
#9 0.993 Reading package lists...
#9 1.248 Building dependency tree...
#9 1.303 Reading state information...
#9 1.386 Solving dependencies...
#9 1.401 Some packages could not be installed. This may mean that you have
#9 1.401 requested an impossible situation or if you are using the unstable
#9 1.401 distribution that some required packages have not yet been created
#9 1.401 or been moved out of Incoming.
#9 1.401 The following information may help to resolve the situation:
#9 1.401
#9 1.401 The following packages have unmet dependencies:
#9 1.401  clang-21 : Depends: libstdc++-15-dev but it is not installable
#9 1.401             Depends: libgcc-15-dev but it is not installable
#9 1.401             Depends: libobjc-15-dev but it is not installable
#9 1.401  clang-tools-21 : Depends: libxml2-16 (>= 2.14.1) but it is not installable
#9 1.401  libclang-21-dev : Depends: libstdc++-15-dev but it is not installable
#9 1.401                    Depends: libgcc-15-dev but it is not installable
#9 1.401                    Depends: libobjc-15-dev but it is not installable
#9 1.401  libclang-cpp21-dev : Depends: libstdc++-15-dev but it is not installable
#9 1.401                       Depends: libgcc-15-dev but it is not installable
#9 1.401  libllvm21 : Depends: libxml2-16 (>= 2.14.1) but it is not installable
#9 1.401  lldb-21 : Depends: liblldb-21 but it is not going to be installed
#9 1.401            Depends: libxml2-16 (>= 2.14.1) but it is not installable
#9 1.401            Depends: python3-lldb-21 but it is not going to be installed
#9 1.402 E: Unable to correct problems, you have held broken packages.
#9 1.402 E: The following information from --solver 3.0 may provide additional context:
#9 1.402    Unable to satisfy dependencies. Reached two conflicting decisions:
#9 1.402    1. libclang-21-dev:amd64=1:21.1.3~++20251015093208+bd9bc536b4ac-1~exp1~20251015093339.49 is selected for install
#9 1.402    2. libclang-21-dev:amd64 Depends libstdc++-15-dev
#9 1.402       but none of the choices are installable:
#9 1.402       [no choices]
#9 ERROR: process "/bin/sh -c /root/llvm.sh 21 all && apt-get install -y clang-21-doc libomp-21-doc llvm-21-doc" did not complete successfully: exit code: 100
------
 > [5/6] RUN /root/llvm.sh 21 all && apt-get install -y clang-21-doc libomp-21-doc llvm-21-doc:
1.401  lldb-21 : Depends: liblldb-21 but it is not going to be installed
1.401            Depends: libxml2-16 (>= 2.14.1) but it is not installable
1.401            Depends: python3-lldb-21 but it is not going to be installed
1.402 E: Unable to correct problems, you have held broken packages.
1.402 E: The following information from --solver 3.0 may provide additional context:
1.402    Unable to satisfy dependencies. Reached two conflicting decisions:
1.402    1. libclang-21-dev:amd64=1:21.1.3~++20251015093208+bd9bc536b4ac-1~exp1~20251015093339.49 is selected for install
1.402    2. libclang-21-dev:amd64 Depends libstdc++-15-dev
1.402       but none of the choices are installable:
1.402       [no choices]
------
Dockerfile:15

[shmerl]

The problem that I'm describing is with unstable itself. I.e. it should not depend on libxml2 which simply doesn't exist anymore (in unstable and testing). I.e. it's not about trixie / stable which still has it:
https://packages.debian.org/trixie/libxml2