[Nix-dev] Almost 50% of all Hydra jobs for Nixpgks/master don't compile

[Peter Simons]

Hi guys,

a large number of Nixpkgs/master builds scheduled on Hydra fail -- mostly
builds on little-used platforms such as FreeBSD. That is an undesirable
situation. There is little point in having Hydra attempt thousands of builds
every day that are known to fail anyway!

Personally, I blame Eelco for all of this, but that doesn't seem to help
remedy the issue. So I'd like to call on all package maintainers to please
double-check the values of

               meta.platforms     and     meta.hydraPlatforms

that you've configured for those packages that you care about.

 * "meta.platforms" can be used to prohibit any and all attempts to build
   that package on platforms you haven't listed. Linux kernel packages, for
   instance, should set "platforms" to student.lib.platforms.linux, because
   it makes no sense to try to build those packages anywhere else. However,
   the majority of packages should specify no "platforms" at all!

 * "meta.hydraPlatforms", on the other hand, specifies the list of platforms
   for which Hydra will build that particular package. Obviously, that list
   should be a subset of "meta.platforms". If your attribute configures a
   large list of Hydra platforms, then please check that those builds
   actually succeed at <http://hydra.nixos.org/jobset/nixpkgs/trunk>. If
   they don't, then you should either (a) fix the build or (b) remove the
   broken platform from the list.

Packages that don't build on any platform at all, should be marked with
'meta.broken = true' (and their hydraPlatforms should probably be empty,
too).

Take care,
Peter