Only show/build a package on the platforms listed in meta.platforms

The function ‘mkDerivation’ now checks whether the current platform
type is included in a package's meta.platform field.  If not, it
throws an exception:

  $ nix-build -A linux --argstr system x86_64-darwin
  error: user-thrown exception: the package ‘linux-3.10.15’ is not supported on ‘x86_64-darwin’

These packages also no longer show up in ‘nix-env -qa’ output.  This
means, for instance, that the number of packages shown on
x86_64-freebsd has dropped from 9268 to 4764.

Since meta.platforms was also used to prevent Hydra from building some
packages, there now is a new attribute meta.hydraPlatforms listing the
platforms on which Hydra should build the package (which defaults to
meta.platforms).

1 files changed, 6 insertions, 3 deletions

diff --git a/pkgs/applications/version-management/darcs/default.nix b/pkgs/applications/version-management/darcs/default.nix
index f33e479b3ada..8ec65e50adf3 100644
--- a/pkgs/applications/version-management/darcs/default.nix
+++ b/pkgs/applications/version-management/darcs/default.nix
@@ -21,10 +21,13 @@ cabal.mkDerivation (self: {
     mv contrib/darcs_completion $out/etc/bash_completion.d/darcs
   '';
   meta = {
-    homepage = "http://darcs.net/";
-    description = "a distributed, interactive, smart revision control system";
+    homepage = http://darcs.net/;
+    description = "A distributed, interactive, smart revision control system";
     license = "GPL";
-    platforms = self.ghc.meta.platforms;
+    # FIXME: this gives an infinite recursion in the "darcs" attribute
+    # in all-packages.nix.
+    #platforms = self.ghc.meta.platforms;
+    platforms = [ "x86_64-linux" "i686-linux" "x86_64-darwin" ];
     maintainers = [ self.stdenv.lib.maintainers.andres ];
   };
 })