Merge pull request #63701 from basvandijk/composable-mkshell-shellHook

Improve composability of mkShell

pkgs/build-support/mkshell/default.nix

@@ -11,13 +11,8 @@
   ...
 }@attrs:
 let
-  mergeInputs = name:
-    let
-      op = item: sum: sum ++ item."${name}" or [];
-      nul = [];
-      list = [attrs] ++ inputsFrom;
-    in
-      lib.foldr op nul list;
+  mergeInputs = name: lib.concatLists (lib.catAttrs name
+    ([attrs] ++ inputsFrom));
 
   rest = builtins.removeAttrs attrs [
     "inputsFrom"
@@ -25,6 +20,7 @@ let
     "nativeBuildInputs"
     "propagatedBuildInputs"
     "propagatedNativeBuildInputs"
+    "shellHook"
   ];
 in
 
@@ -37,6 +33,9 @@ stdenv.mkDerivation ({
   propagatedBuildInputs = mergeInputs "propagatedBuildInputs";
   propagatedNativeBuildInputs = mergeInputs "propagatedNativeBuildInputs";
 
+  shellHook = lib.concatStringsSep "\n" (lib.catAttrs "shellHook"
+    (lib.reverseList inputsFrom ++ [attrs]));
+
   nobuildPhase = ''
     echo
     echo "This derivation is not meant to be built, aborting";