proposal for ghc-pkg to use a directory of .conf files

[Isaac Jones]

"Simon Marlow" <simonmar at microsoft.com> writes:

> On 08 November 2004 18:47, Duncan Coutts wrote:
>
>> We can use ghc-pkg at the build / install-into-temp phase to create
>> the $(package).conf files under
>> $TMP_INSTALL_ROOT/usr/lib/ghc-$VER/package.conf.d/ and then final
>> installation is jsut merging files without any post-install calls to
>> ghc-pkg to modify installed files (ie the global ghc package.conf
>> file) 
>> 
>> So we can still keep the abstraction of $HC-pkg and gain simpler
>> packaging stuff.
>
> Ok, sounds reasonable.
>
> I'm going to be working on the package support in ghc and ghc-pkg to
> improve support for Cabal, so let's do this at the same time.

As a Debian packager, I like the idea of changing the way HC-PKG
handles individual packages.

The question in my mind is whether we want to execute any code on the
install target.  Previously, I have thought of "./setup register" as
being a step that happens on the target, no matter what.  So if Marcus
Makefile wants to do something specifically for the target at install
time, this is where he could do it.

If we go this route and have the package registration happen at
install-in-temp time, then we don't have any standard way to run a
post-install script.  Some people may prefer that we never execute
anything from Cabal on the target, but I would prefer to leave that
ability.

One solution would be to move the registration step into
install-into-temp time, as above, but to add another standard command
to Cabal like "./setup postinstall" and maybe some others "preinst,
prerm, postrm" as in Debian.

This would solve both problems; haskell packages installed with a
packaging system like Debian would usually just be moving files into
place, but if Marcus or Angela really needed to run something on the
target, this is how they'd do it.

Thoughts?

peace,

  isaac