lib/utils: add mkWarnings

lib/default.nix

@@ -86,6 +86,7 @@ lib.makeExtensible (
       mkIfNonNull'
       mkRaw
       mkRawKey
+      mkWarnings
       nestedLiteral
       nestedLiteralLua
       override

lib/utils.nix

@@ -158,6 +158,7 @@ rec {
     ```
 
     # Type
+
     ```
     literalLua :: String -> AttrSet
     ```
@@ -172,6 +173,34 @@ rec {
     in
     lib.literalExpression exp;
 
+  /**
+    Convert one or several conditional warnings to a final warning list.
+    The second argument can either be a list of _conditional warnings_ or a single one.
+
+    # Example
+
+    ```nix
+    warnings = mkWarnings "plugins.foo" {
+      when = plugins.foo.settings.barIntegration && (!plugins.bar.enable);
+      message = "`barIntegration` is enabled but the `bar` plugin is not."
+    }
+    ```
+
+    # Type
+
+    ```
+    mkWarnings :: String -> List -> List
+    ```
+  */
+  mkWarnings =
+    scope: warnings:
+    let
+      processWarning =
+        warning:
+        lib.optional (warning.when or true) "Nixvim (${scope}): ${lib.trim (warning.message or warning)}";
+    in
+    builtins.concatMap processWarning (lib.toList warnings);
+
   /**
     Convert the given string into a `__pretty` printed mkRaw expression.
 
@@ -190,6 +219,7 @@ rec {
     ```
 
     # Type
+
     ```
     nestedLiteralLua :: String -> AttrSet
     ```
@@ -221,6 +251,7 @@ rec {
     ```
 
     # Type
+
     ```
     nestedLiteral :: (String | literalExpression) -> AttrSet
     ```

tests/lib-tests.nix

@@ -490,6 +490,30 @@ let
         "mkAfter list".foo.bar = lib.mkAfter "Hello!";
       };
     };
+
+    testMkWarnings = {
+      expr =
+        (lib.nixvim.mkWarnings "foo-bar" [
+          {
+            when = true;
+            message = "This is the message";
+          }
+          {
+            when = false;
+            message = "This should not be included";
+          }
+          "This is an unconditional warning"
+        ])
+        ++ (lib.nixvim.mkWarnings "single-element") {
+          when = true;
+          message = "Hello";
+        };
+      expected = [
+        "Nixvim (foo-bar): This is the message"
+        "Nixvim (foo-bar): This is an unconditional warning"
+        "Nixvim (single-element): Hello"
+      ];
+    };
   };
 in
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