lib: mkTypedMerge: fix to work with recursive attrsets

modules/lib/default.nix

@@ -20,9 +20,13 @@ sane-lib = rec {
   isPrefixOfList = p: l: (lib.sublist 0 (lib.length p) l) == p;
 
   # merges N attrsets
-  # Type: flattenAttrsList :: [AttrSet] -> AttrSet
+  # Type: joinAttrsets :: [AttrSet] -> AttrSet
   joinAttrsets = l: lib.foldl' lib.attrsets.unionOfDisjoint {} l;
 
+  # merges N attrsets, recursively
+  # Type: joinAttrsetsRecursive :: [AttrSet] -> AttrSet
+  joinAttrsetsRecursive = l: lib.foldl' (lib.attrsets.recursiveUpdateUntil (path: lhs: rhs: false)) {} l;
+
   # evaluate a `{ name, value }` pair in the same way that `listToAttrs` does.
   # Type: nameValueToAttrs :: { name :: String, value :: Any } -> Any
   nameValueToAttrs = { name, value }: {

modules/lib/merge.nix

@@ -17,7 +17,7 @@ rec {
       merged = builtins.map (p: lib.setAttrByPath p (mergeAtPath p discharged)) pathsToMerge;
     in
       assert builtins.all (assertNoExtraPaths pathsToMerge) discharged;
-      sane-lib.joinAttrsets merged;
+      sane-lib.joinAttrsetsRecursive merged;
 
   # `take` is as in mkTypedMerge. this function queries which items `take` is interested in.
   # for example: