bash-completion.pc doesn't allow to redefine prefix variable

[Enrique]

On Ubuntu 19.10 the file /usr/share/pkgconfig/bash-completion.pc has hard-coded values for completionsdir and helpersdir:

# cat /usr/share/pkgconfig/bash-completion.pc
prefix=/usr
compatdir=/etc/bash_completion.d
completionsdir=/usr/share/bash-completion/completions
helpersdir=/usr/share/bash-completion/helpers

 whereas in Ubuntu 19.04 it looks like this:

# cat /usr/share/pkgconfig/bash-completion.pc
prefix=/usr
compatdir=/etc/bash_completion.d
completionsdir=${prefix}/share/bash-completion/completions
helpersdir=${prefix}/share/bash-completion/helpers

 the problem with the first one is that one cannot override the prefix variable:

Ubuntu 19.10:
# pkg-config --variable=completionsdir --define-variable=prefix=/other_dir bash-completion
/usr/share/bash-completion/completions

Ubuntu 19.04:
# pkg-config --variable=completionsdir --define-variable=prefix=/other_dir bash-completion
/other_dir/share/bash-completion/completions

 This is a problem for software that tries to install as a non-root user software in non-system directories.

 The problem is known upstream and has been fixed:
https://github.com/scop/bash-completion/commit/8c5302581ad20954cfa164dcae26f1ed6277dd90#diff-42e567633e7af054a0d01d8f2b93ddf1

Updating the version of bash-completion to 2.10 (https://github.com/scop/bash-completion/releases/tag/2.10) will help to fix the issue. In the new version completionsdir is defined in terms of datadir, so a way to verify that the bug is fixed and one gets the same thing in Ubuntu 19.06 and Ubuntu 19.10 would be:

# pkg-config --variable=completionsdir --define-variable=datadir=/other_dir/share --define-variable=prefix=/other_dir bash-completion
/other_dir/share/bash-completion/completions

 The currently installed package in my system:

# apt-cache policy bash-completion
bash-completion:
  Installed: 1:2.9-1ubuntu1
  Candidate: 1:2.9-1ubuntu1
  Version table:
 *** 1:2.9-1ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu eoan/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: bash-completion 1:2.9-1ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-65.74-generic 4.15.18
Uname: Linux 4.15.0-65-generic x86_64
ApportVersion: 2.20.11-0ubuntu8.2
Architecture: amd64
Date: Wed Dec 18 11:44:40 2019
Dependencies:

PackageArchitecture: all
SourcePackage: bash-completion
UpgradeStatus: No upgrade log present (probably fresh install)

[Enrique (enrique-garcia)]

Hi,

this bug seems to be have a well defined patch upstream. Would it be possible to apply it to Ubuntu 19.10?
Also, it would be good that a patched version of bash-completion is included in 20.04.