From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH] build-system: Add haskell-build-system.
Date: Mon, 30 Mar 2015 10:16:49 +0200
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	(Federico Beffa's message of "Sun, 29 Mar 2015 16:45:38 +0200")
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To: Federico Beffa <beffa@ieee.org>
Cc: Guix-devel <guix-devel@gnu.org>

Federico Beffa <beffa@ieee.org> skribis:

> Having never used nixpkgs, I'm not sure how they handle the database
> in profiles. Would you have a pointer to a "standard" mechanism (like
> how they handle 'dir' files, icon caches, ...).

AFAIK there=E2=80=99s no general mechanism for that.  For GHC, this is hand=
led
by adding a wrapper for the =E2=80=98ghc=E2=80=99 binary:

  https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/compilers/g=
hc/wrapper.nix
  https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/compilers/g=
hcjs/wrapper.nix

Handling it during profile creation, as you suggest, and avoiding the
use of a wrapper sounds preferable to me.

If you look under
<https://github.com/NixOS/nixpkgs/tree/master/pkgs/desktops/gnome-3/3.12/co=
re>,
many packages have an additional phase that does:

  rm $out/share/icons/hicolor/icon-theme.cache

Some also explicitly wrap executables to set XDG_DATA_DIRS etc. like our
=E2=80=98glib-or-gtk-build-system=E2=80=99 does:

  wrapProgram $f \
    --prefix XDG_DATA_DIRS : "$XDG_ICON_DIRS:$GSETTINGS_SCHEMAS_PATH"

Thanks,
Ludo=E2=80=99.