How to use @preexec to test for installed packages

[Adam Weinberger]

On Sat, Apr 6, 2019 at 12:49 PM Miroslav Lachman <000.fbsd at quip.cz> wrote:
>
> Matthew Seaman wrote on 2019/04/06 19:00:
> > On 06/04/2019 14:58, Matthias Fechner wrote:
> >
> >> as pkg cannot handle CONFLICTS_INSTALL I tried now to implement this as
> >> a preinstall command using @preexec in pkg-plist.
> >>
> >> The command should check if a package is installed and stop the
> >> installation or continue if the package is not installed.
> >>
> >> I tried it with the following command:
> >> @preexec `/usr/sbin/pkg -N info -e gogs`; if [ $? -eq 0 ]; then echo
> >> "Gitlab cannot be installed together with gogs as both of them modify
> >> .ssh/authorized_keys" && exit 1; else echo "Gogs not installed,
> >> continue."; fi
> >>
> >> But it does not work.
> >> Now matter if gogs is installed or not.
> >> If I execute the same line in a shell script, it works fine.
> >>
> >> Anyone an idea?
> >
> > pkg(8) does handle the most common reason for packages conflicting at
> > install time -- file name clashes.  Indeed, it does this automatically
> > with no need of input from porters or maintainers, although it is usual
> > to add CONFLICTS_INSTALL lines to port Makefiles to document clashes
> > discovered this way.
> >
> > However, where there are other reasons for packages to conflict at
> > install time, then you are correct that pkg doesn't handle this.
> > There's simply no mechanism to include information about package
> > conflicts into pkg metadata.
>
> Then you can add some fake (empty) file to the plist of package A which
> will conflict with package B and then pkg conflict will work as expected.
> But I am not sure we should prevent installation of some package just
> because it uses authorized_keys too.

Especially since www/gitea does the same thing (and probably a number
of others as well).

# Adam


-- 
Adam Weinberger
adamw at adamw.org
https://www.adamw.org