2 files changed, 32 insertions, 13 deletions
diff --git a/pkgs/top-level/release-cross.nix b/pkgs/top-level/release-cross.nix
index ef99dbd619e..0d15d817a66 100644
--- a/pkgs/top-level/release-cross.nix
+++ b/pkgs/top-level/release-cross.nix
@@ -88,7 +88,7 @@ in
         f (["buildPackages"] ++ path) { inherit system crossSystem; }
       );
 
-    testEqual = path: systems: forTheseSystems systems (testEqualOne path);
+    testEqual = path: systems: forMatchingSystems systems (testEqualOne path);
 
     mapTestEqual = lib.mapAttrsRecursive testEqual;
 
diff --git a/pkgs/top-level/release-lib.nix b/pkgs/top-level/release-lib.nix
index dbeb13d4bd3..b410348d1e8 100644
--- a/pkgs/top-level/release-lib.nix
+++ b/pkgs/top-level/release-lib.nix
@@ -48,33 +48,56 @@ rec {
   pkgs_x86_64_cygwin = allPackages { system = "x86_64-cygwin"; };
 
 
+  # Given a list of 'meta.platforms'-style patterns, return the sublist of
+  # `supportedSystems` containing systems that matches at least one of the given
+  # patterns.
+  #
+  # This is written in a funny way so that we only elaborate the systems once.
+  supportedMatches = let
+      supportedPlatforms = map
+        (system: lib.systems.elaborate { inherit system; })
+        supportedSystems;
+    in metaPatterns: let
+      anyMatch = platform:
+        lib.any (lib.meta.platformMatch platform) metaPatterns;
+      matchingPlatforms = lib.filter anyMatch supportedPlatforms;
+    in map ({ system, ...}: system) matchingPlatforms;
+
+
   assertTrue = bool:
     if bool
     then pkgs.runCommand "evaluated-to-true" {} "touch $out"
     else pkgs.runCommand "evaluated-to-false" {} "false";
 
+
   /* The working or failing mails for cross builds will be sent only to
      the following maintainers, as most package maintainers will not be
      interested in the result of cross building a package. */
   crossMaintainers = [ maintainers.viric ];
 
+
+  # Generate attributes for all supported systems.
   forAllSystems = genAttrs supportedSystems;
-  forTheseSystems = systems: f:
-    genAttrs (filter (x: elem x supportedSystems) systems) f;
+
+
+  # Generate attributes for all sytems matching at least one of the given
+  # patterns
+  forMatchingSystems = metaPatterns: genAttrs (supportedMatches metaPatterns);
+
 
   /* Build a package on the given set of platforms.  The function `f'
      is called for each supported platform with Nixpkgs for that
      platform as an argument .  We return an attribute set containing
      a derivation for each supported platform, i.e. ‘{ x86_64-linux =
      f pkgs_x86_64_linux; i686-linux = f pkgs_i686_linux; ... }’. */
-  testOn = systems: f: forTheseSystems systems
+  testOn = metaPatterns: f: forMatchingSystems metaPatterns
     (system: hydraJob' (f (pkgsFor system)));
 
 
   /* Similar to the testOn function, but with an additional
      'crossSystem' parameter for allPackages, defining the target
      platform for cross builds. */
-  testOnCross = crossSystem: systems: f: forTheseSystems systems
+  testOnCross = crossSystem: metaPatterns: f: forMatchingSystems metaPatterns
     (system: hydraJob' (f (allPackages { inherit system crossSystem; })));
 
 
@@ -82,14 +105,14 @@ rec {
      map each leaf node to `testOn [platforms...] (pkgs:
      pkgs.<attrPath>)'. */
   mapTestOn = mapAttrsRecursive
-    (path: systems: testOn systems (pkgs: getAttrFromPath path pkgs));
+    (path: metaPatterns: testOn metaPatterns (pkgs: getAttrFromPath path pkgs));
 
 
   /* Similar to the testOn function, but with an additional 'crossSystem'
    * parameter for allPackages, defining the target platform for cross builds,
    * and triggering the build of the host derivation (cross built - crossDrv). */
   mapTestOnCross = crossSystem: mapAttrsRecursive
-    (path: systems: testOnCross crossSystem systems
+    (path: metaPatterns: testOnCross crossSystem metaPatterns
       (pkgs: addMetaAttrs { maintainers = crossMaintainers; } (getAttrFromPath path pkgs)));
 
 
@@ -98,12 +121,8 @@ rec {
   packagePlatforms = mapAttrs (name: value:
     let res = builtins.tryEval (
       if isDerivation value then
-        value.meta.hydraPlatforms or (let
-            linuxDefaulted = value.meta.platforms or [ "x86_64-linux" ];
-            pred = system: lib.any
-              (lib.meta.platformMatch (lib.systems.elaborate { inherit system; }))
-              linuxDefaulted;
-          in lib.filter pred supportedSystems)
+        value.meta.hydraPlatforms
+          or supportedMatches (value.meta.platforms or [ "x86_64-linux" ])
       else if value.recurseForDerivations or false || value.recurseForRelease or false then
         packagePlatforms value
       else