The bash-completion and fish dependencies were already optional - the
shell completions for Bash and fish won't be generated and installed if
they are absent; and there's no dependency required for Z shell. So the
install_completions build option wasn't reducing the dependency burden.
The build option was a way to disable the generation and installation of
the shell completions, regardless of whether the necessary dependencies
are present or not. The only use-case for this is when installing to a
non-system-wide prefix while hacking on Toolbox as a non-root user,
because the locations for the completions advertised by the shells' APIs
might not be accessible. Being able to disable the completions prevents
the installation from failing.
A different way of ensuring a smooth developer experience for a Toolbx
hacker is to offer a way to change the locations where the shell
completions are installed, which is necessary and beneficial for other
use-cases.
Z shell, unlike Bash's bash-completion.pc and fish's fish.pc, doesn't
offer an API to detect the location for the shell completions. This
means that Debian and Fedora use different locations [1, 2]. Namely,
/usr/share/zsh/vendor-completions and /usr/share/zsh/site-functions.
An option to specify the locations for the shell completions can
optimize the build, if there's an alternate API for the location that
doesn't involve using bash-completion.pc and fish.pc as build
dependencies. eg., Fedora provides the _tmpfilesdir RPM macro to
specify the location for vendor-supplied tmpfiles.d(5) files, which
makes it possible to avoid having systemd.pc as a build dependency [3].
Fallout from bafbbe81c9
[1] Debian zsh commit bf0a44a8744469b5
https://salsa.debian.org/debian/zsh/-/commit/bf0a44a8744469b5https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=620452
[2] https://src.fedoraproject.org/rpms/zsh/blob/f37/f/zsh.spec
[3] Fedora toolbox commit 9bebde5bb60f36e3
https://src.fedoraproject.org/rpms/toolbox/c/9bebde5bb60f36e3https://github.com/containers/toolbox/pull/1123https://github.com/containers/toolbox/pull/840
5d26b9d71d