stylix: check whether maintainers list is sorted (#1014)

Link: https://github.com/danth/stylix/pull/1014

Reviewed-by: NAHO <90870942+trueNAHO@users.noreply.github.com>

flake.nix

@@ -148,6 +148,8 @@
 
             src = ./.;
           };
+
+          maintainers-sorted = (import ./stylix/check-maintainers-sorted.nix) pkgs;
         } self.packages.${system};
 
         devShells = {

stylix/check-maintainers-sorted.nix

@@ -0,0 +1,87 @@
+# slight modification from nixpkgs's script: https://github.com/NixOS/nixpkgs/commit/4a694fc50007076566a204d6ea623fd5fc7ddbfa
+pkgs:
+let
+  inherit (pkgs.lib)
+    add
+    attrNames
+    attrValues
+    elemAt
+    foldl'
+    genList
+    length
+    replaceStrings
+    sort
+    toLower
+    trace
+    ;
+
+  maintainers = import ./maintainers.nix;
+  simplify = replaceStrings [ "-" "_" ] [ "" "" ];
+  namesSorted = sort (a: b: a.key < b.key) (
+    map (
+      n:
+      let
+        pos = builtins.unsafeGetAttrPos n maintainers;
+      in
+      assert pos == null -> throw "maintainers entry ${n} is malformed";
+      {
+        name = n;
+        inherit (pos) line;
+        key = toLower (simplify n);
+      }
+    ) (attrNames maintainers)
+  );
+  before =
+    {
+      key,
+      ...
+    }:
+    foldl' (
+      acc: n: if n.key < key && (acc == null || n.key > acc.key) then n else acc
+    ) null namesSorted;
+  errors = foldl' add 0 (
+    map (
+      i:
+      let
+        a = elemAt namesSorted i;
+        b = elemAt namesSorted (i + 1);
+        lim =
+          let
+            t = before a;
+          in
+          if t == null then "the initial {" else t.name;
+      in
+      if a.line >= b.line then
+        trace (
+          "maintainer ${a.name} (line ${toString a.line}) should be listed "
+          + "after ${lim}, not after ${b.name} (line ${toString b.line})"
+        ) 1
+      else
+        0
+    ) (genList (i: i) (length namesSorted - 1))
+  );
+in
+assert length (attrValues maintainers) < 1 || errors == 0;
+pkgs.runCommandLocal "maintainers-sorted" { } "mkdir $out"
+
+# generate edit commands to sort the list.
+# may everything following the last current entry (closing } ff) in the wrong place
+# with lib;
+# concatStringsSep
+#   "\n"
+#   (let first = foldl' (acc: n: if n.line < acc then n.line else acc) 999999999 namesSorted;
+#        commands = map
+#          (i: let e = elemAt namesSorted i;
+#                  begin = foldl'
+#                    (acc: n: if n.line < e.line && n.line > acc then n.line else acc)
+#                    1
+#                    namesSorted;
+#                  end =
+#                    foldl' (acc: n: if n.line > e.line && n.line < acc then n.line else acc)
+#                      999999999
+#                      namesSorted;
+#              in "${toString e.line},${toString (end - 1)} p")
+#          (genList (i: i) (length namesSorted));
+#    in map
+#      (c: "sed -ne '${c}' maintainers/maintainer-list.nix")
+#      ([ "1,${toString (first - 1)} p" ] ++ commands))