From dc7589b2585f70dab3964c8edc9d1780178a1a22 Mon Sep 17 00:00:00 2001
From: diniamo <diniamo53@gmail.com>
Date: Tue, 9 Jul 2024 00:49:15 +0200
Subject: [PATCH] lib/types(custom): clarify anythingConcatLists code

---
 lib/types/custom.nix | 65 ++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 33 deletions(-)

diff --git a/lib/types/custom.nix b/lib/types/custom.nix
index e9973bfa..f4065155 100644
--- a/lib/types/custom.nix
+++ b/lib/types/custom.nix
@@ -2,12 +2,12 @@
   inherit (lib) isStringLike showOption showFiles getFiles mergeOneOption mergeEqualOption;
   inherit (lib.types) anything attrsOf;
   inherit (lib.nvim.types) anythingConcatLists;
-  inherit (builtins) isAttrs foldl' head concatLists;
+  inherit (builtins) typeOf isAttrs any head concatLists;
 in {
+  # HACK: Does this break anything in our case?
   # A modified version of the nixpkgs anything type that concatenates lists
   # This isn't the default because the order in which the lists are concatenated depends on the order in which the modules are imported,
   # which makes it non-deterministic
-  # HACK: Does this break anything in our case?
   anythingConcatLists =
     anything
     // {
@@ -15,40 +15,39 @@ in {
         getType = value:
           if isAttrs value && isStringLike value
           then "stringCoercibleSet"
-          else builtins.typeOf value;
+          else typeOf value;
 
-        # Returns the common type of all definitions, throws an error if they
-        # don't have the same type
+        # Throw an error if not all defs have the same type
+        checkType = getType (head defs).value;
         commonType =
-          foldl' (
-            type: def:
-              if getType def.value == type
-              then type
-              else throw "The option `${showOption loc}' has conflicting option types in ${showFiles (getFiles defs)}"
-          ) (getType (head defs).value)
-          defs;
+          if any (def: getType def.value != checkType) defs
+          then throw "The option `${showOption loc}' has conflicting option types in ${showFiles (getFiles defs)}"
+          else checkType;
 
-        mergeFunction =
-          {
-            # Recursively merge attribute sets
-            set = (attrsOf anythingConcatLists).merge;
-            # Overridden behavior for lists
-            list = _: defs: concatLists (map (e: e.value) defs);
-            # This is the type of packages, only accept a single definition
-            stringCoercibleSet = mergeOneOption;
-            lambda = loc: defs: arg:
-              anythingConcatLists.merge
-              (loc ++ ["<function body>"])
-              (map (def: {
-                  inherit (def) file;
-                  value = def.value arg;
-                })
-                defs);
-            # Otherwise fall back to only allowing all equal definitions
-          }
-          .${commonType}
-          or mergeEqualOption;
+        mergeFunctions = {
+          # Recursively merge attribute sets
+          set = (attrsOf anythingConcatLists).merge;
+
+          # Overridden behavior for lists, that concatenates lists
+          list = _: defs: concatLists (map (e: e.value) defs);
+
+          # This means it's a package, only accept a single definition
+          stringCoercibleSet = mergeOneOption;
+
+          # This works by passing the argument to the functions,
+          # and merging their returns values instead
+          lambda = loc: defs: arg:
+            anythingConcatLists.merge
+            (loc ++ ["<function body>"])
+            (map (def: {
+                inherit (def) file;
+                value = def.value arg;
+              })
+              defs);
+        };
       in
-        mergeFunction loc defs;
+        # Merge the defs with the correct function from above, if available
+        # otherwise only allow equal values
+        (mergeFunctions.${commonType} or mergeEqualOption) loc defs;
     };
 }