From 4141be04fe0f3d76ab18268729eee09f070614e9 Mon Sep 17 00:00:00 2001
From: Adam Joseph <adam@westernsemico.com>
Date: Wed, 2 Aug 2023 12:05:18 -0700
Subject: [PATCH] stdenv: use shallow checking for meta.platforms (deep for
 bad*Platforms)

---
 lib/meta.nix                       | 12 ++++++------
 pkgs/stdenv/generic/check-meta.nix | 24 +++++++++++-------------
 2 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/lib/meta.nix b/lib/meta.nix
index 46f101db1e17c..e3a7faf568ff9 100644
--- a/lib/meta.nix
+++ b/lib/meta.nix
@@ -111,20 +111,20 @@ rec {
 
   /* Check a platform against an availability.
 
-     An availability is an attrset with two attributes:
-     - `bad`:  a list          of platform patterns accepted by platformMatch
-     - `only`: a list of lists of platform patterns accepted by platformMatch
+     An availability is an attrset with two attributes `bad` and
+     `only`; each is a list of platform patterns accepted by
+     platformMatch.
 
      To match the availability, both of the following must be true:
      - The platform must not match any element of `bad`
-     - For each sublist of `only`, the platform must match at least one element of the sublist.
+     - If `only` is nonempty, the platform must match at least one element of the sublist.
   */
   checkAvailability = platform: availability:
     # Must not match any of availability.bad
     !(lib.any                    (elem: platformMatch platform elem)          (availability.bad or []))
 
-    # For all sublists of availability.only, must match at least one sublist element
-    && lib.all (sublist: lib.any (elem: platformMatch platform elem) sublist) (availability.only or [])
+    # If availability.only is non-empty, must match at least one sublist element
+    && availability?only -> ((builtins.length availability.only != 0) -> lib.any (elem: platformMatch platform elem) availability.only)
   ;
 
   /* Get the corresponding attribute in lib.licenses
diff --git a/pkgs/stdenv/generic/check-meta.nix b/pkgs/stdenv/generic/check-meta.nix
index 84c5c32cc0bb7..7b25763a2c8d5 100644
--- a/pkgs/stdenv/generic/check-meta.nix
+++ b/pkgs/stdenv/generic/check-meta.nix
@@ -66,7 +66,7 @@ let
       };
       checkHostPlatform = checkAvailability hostPlatform {
         bad = (attrs.meta.badPlatforms or []) ++ (attrs.meta.badHostPlatforms or []);
-        only = lib.optionals (attrs?meta.platforms) [ attrs.meta.platforms ];
+        only = lib.optionals (attrs?meta.platforms && attrs.meta.platforms != lib.platforms.all) attrs.meta.platforms;
       };
       checkTargetPlatform = checkAvailability targetPlatform {
         bad = attrs.meta.badTargetPlatforms or [];
@@ -483,16 +483,17 @@ let
       availability = let meta = attrs.meta or {}; in {
         build = {
           bad = lexicographicUniques (
-            (map (pkg: pkg.meta.availability.host.bad or []) referencesOnBuild) ++
-            (map (pkg: pkg.meta.availability.build.bad or []) referencesOnHost) ++
-            [ (meta.badBuildPlatforms or []) ]
+            (meta.badBuildPlatforms or []) ++
+            (builtins.concatMap (pkg: pkg.meta.availability.build.bad or []) referencesOnHost) ++
+            (builtins.concatMap (pkg: pkg.meta.availability.host.bad or []) referencesOnBuild)
           );
         };
         host = {
           bad = lexicographicUniques (
-            (map (pkg: pkg.meta.availability.target.bad or []) referencesOnBuild) ++
-            (map (pkg: pkg.meta.availability.host.bad or []) referencesOnHost) ++
-            [ (meta.badPlatforms or []) ]
+            (meta.badPlatforms or []) ++
+            (meta.badHostPlatforms or []) ++
+            (builtins.concatMap (pkg: pkg.meta.availability.host.bad or []) referencesOnHost) ++
+            (builtins.concatMap (pkg: pkg.meta.availability.target.bad or []) referencesOnBuild)
           );
 
           # "host.only" is needed to represent the (deprecated,
@@ -504,14 +505,12 @@ let
           # There are no build.only or target.only attrsets because
           # we (thankfully) don't have meta.platforms equivalents
           # for those.
-          only = (
-            (lib.optionals (meta?platforms && meta.platforms != lib.platforms.all) [ meta.platforms ])
-          );
+          only = lib.optionals (meta?platforms && meta.platforms != lib.platforms.all) meta.platforms;
         };
         target = {
           bad = lexicographicUniques (
-            (map (pkg: pkg.meta.availability.target.bad or []) referencesOnHost) ++
-            [ (meta.badTargetPlatforms or []) ]
+            (meta.badTargetPlatforms or []) ++
+            (builtins.concatMap (pkg: pkg.meta.availability.target.bad or []) referencesOnHost)
           );
         };
       };
@@ -534,7 +533,6 @@ let
   # O(n log n)
   # TODO(amjoseph@): possibly move to /lib/
   lexicographicUniques = lists: lib.pipe lists [
-    builtins.concatLists                               # O(n)
     (map (x: assert (lib.isAttrs x || lib.isString x); x))
     (lib.sort (x: y: lexicographicCompare x y < 0))    # O(n log n)
     sortedUnique                                       # O(n)