Bug#1104177: libc++-18-dev fails to coinstall

[Helmut Grohne]

Package: libc++-18-dev,libunwind-18-dev,libc++abi1-18,libc++abi-18-dev,libunwind-18
Version: 1:18.1.8-18
Severity: serious
User: debian-qa at lists.debian.org
Usertags: fileconflict

libc++-18-dev explicitly declares the ability to coinstall via
Multi-Arch: same. Attempting to do this practically fails though.

$ mmdebstrap --variant=essential --verbose unstable /dev/null --architectures=amd64,i386 --include=libc++-18-dev,libc++-18-dev:i386
...
Selecting previously unselected package libunwind-18:i386.
Preparing to unpack .../09-libunwind-18_1%3a18.1.8-18_i386.deb ...
Unpacking libunwind-18:i386 (1:18.1.8-18) ...
dpkg: error processing archive /tmp/apt-dpkg-install-869OWv/09-libunwind-18_1%3a18.1.8-18_i386.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-18/lib/libunwind.so.1.0', which is different from other instances of package libunwind-18:i386
Selecting previously unselected package libc++abi1-18:i386.
Preparing to unpack .../10-libc++abi1-18_1%3a18.1.8-18_i386.deb ...
Unpacking libc++abi1-18:i386 (1:18.1.8-18) ...
dpkg: error processing archive /tmp/apt-dpkg-install-869OWv/10-libc++abi1-18_1%3a18.1.8-18_i386.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-18/lib/libc++abi.so.1.0', which is different from other instances of package libc++abi1-18:i386
Selecting previously unselected package libc++1-18:i386.
Preparing to unpack .../11-libc++1-18_1%3a18.1.8-18_i386.deb ...
Unpacking libc++1-18:i386 (1:18.1.8-18) ...
dpkg: error processing archive /tmp/apt-dpkg-install-869OWv/11-libc++1-18_1%3a18.1.8-18_i386.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-18/lib/libc++.so.1.0', which is different from other instances of package libc++1-18:i386
Selecting previously unselected package libc++abi-18-dev:i386.
Preparing to unpack .../12-libc++abi-18-dev_1%3a18.1.8-18_i386.deb ...
Unpacking libc++abi-18-dev:i386 (1:18.1.8-18) ...
dpkg: error processing archive /tmp/apt-dpkg-install-869OWv/12-libc++abi-18-dev_1%3a18.1.8-18_i386.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-18/lib/libc++abi.a', which is different from other instances of package libc++abi-18-dev:i386
Selecting previously unselected package libunwind-18-dev:i386.
Preparing to unpack .../13-libunwind-18-dev_1%3a18.1.8-18_i386.deb ...
Unpacking libunwind-18-dev:i386 (1:18.1.8-18) ...
dpkg: error processing archive /tmp/apt-dpkg-install-869OWv/13-libunwind-18-dev_1%3a18.1.8-18_i386.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-18/lib/libunwind.a', which is different from other instances of package libunwind-18-dev:i386
Selecting previously unselected package libc++-18-dev:i386.
Preparing to unpack .../14-libc++-18-dev_1%3a18.1.8-18_i386.deb ...
Unpacking libc++-18-dev:i386 (1:18.1.8-18) ...
dpkg: error processing archive /tmp/apt-dpkg-install-869OWv/14-libc++-18-dev_1%3a18.1.8-18_i386.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-18/lib/libc++.a', which is different from other instances of package libc++-18-dev:i386
Errors were encountered while processing:
 /tmp/apt-dpkg-install-869OWv/09-libunwind-18_1%3a18.1.8-18_i386.deb
 /tmp/apt-dpkg-install-869OWv/10-libc++abi1-18_1%3a18.1.8-18_i386.deb
 /tmp/apt-dpkg-install-869OWv/11-libc++1-18_1%3a18.1.8-18_i386.deb
 /tmp/apt-dpkg-install-869OWv/12-libc++abi-18-dev_1%3a18.1.8-18_i386.deb
 /tmp/apt-dpkg-install-869OWv/13-libunwind-18-dev_1%3a18.1.8-18_i386.deb
 /tmp/apt-dpkg-install-869OWv/14-libc++-18-dev_1%3a18.1.8-18_i386.deb
E: Sub-process env returned an error code (1)
...
$

Given the freeze timing, I recommend dropping the Multi-Arch
declaration instead of attempting to move files around.

Helmut