[aur-general] Are AUR VCS packages that depend on AUR VCS packages from other projects a good idea and who should decide on that ?

[Doug Newgard]

On Fri, 3 May 2019 10:04:39 -0400
Eli Schwartz via aur-general <aur-general at archlinux.org> wrote:

> On 5/1/19 10:53 AM, Doug Newgard via aur-general wrote:
> > On Wed, 1 May 2019 12:38:41 +0200
> > Lone_Wolf <lonewolf at xs4all.nl> wrote:  
> >> Assumptions :
> >>
> >> mesa-git depends on llvm and llvm-libs
> >>
> >> AUR only has one mesa-git package
> >>
> >> User builds in clean chroot with devtools
> >>
> >> User wants mesa feature X, finds they need to run mesa-git for that.
> >>
> >>
> >> User clones aur mesa-git and builds with extra-x86_64-build
> >>
> >> makepkg sees llvm / llvm-libs dependencies are satisfied by extra/llvm 
> >> and extra/llvm-libs.
> >>
> >> mesa-git is build against those versions
> >>
> >> user installs mesa-git, pacman sees llvm-libs is needed and finds 
> >> extra/llvm-libs installed.
> >>
> >>
> >> User runs mesa-git, realizes feature X is not working.
> >>
> >> Investigation reveals feature X is not supported by stable llvm, user 
> >> needs to built mesa-git against llvm-git.
> >>
> >> User builds llvm-git + llvm-libs-git in clean chroot.
> >>
> >> In order to use the llvm-git for mesa-git building they add the packages 
> >> manually to extra-x86_64-build.
> >>
> >> They now have a mesa-git build against llvm-git and install that.
> >>
> >> pacman sees mesa-git depends on llvm-libs , and that's satisfied by 
> >> extra/llvm-libs.
> >>
> >> user tries again , mesa-git crashes.
> >>
> >>
> >> User asks for help on forum.
> >>
> >> Someone that understands how mesa and llvm interact, suggests they try 
> >> installing llvm-libs-git .
> >>
> >> User installs that, mesa-git works and feature X also works .
> >>
> >> User is happy, tries to figure out how to avoid similar issues in future.
> >>
> >>
> >> Someone points out that the mesa-git crash was caused by pacman being 
> >> unaware which llvm-libs binary version was needed.
> >>
> >> Simple solution : edit depends in PKGBUILD to have mesa-git depend on 
> >> llvm-git / llvm-libs-git .  
> > 
> > Full stop. Solution is not to edit the PKGBUILD, solution is for the
> > theoretical user to not be replacing system libraries when they don't have a
> > clue what they're doing.
> > 
> > You're trying to overcomplicate the system to account for user stupidity. This
> > is Arch, stop doing that.  
> 
> I'm still not really seeing what the problem here is.
> 
> Lone Wolf's point here, is that mesa-git results in different codegen
> and different features, if the build-time compilation environment is
> llvm-git.
> 
> It's not unreasonable to want the resulting package to have technically
> correct dependency linkages when its compilation environment results in
> *different dependencies*.

No different than an soname bump.