fix: avoid incorrect additionalProperties for Pick<..., AliasLiteralUnion> (#2230)

Author: alexchexes

src/NodeParser/MappedTypeNodeParser.ts

@@ -158,7 +158,7 @@ export class MappedTypeNodeParser implements SubNodeParser {
         keyListType: UnionType,
         context: Context,
     ): BaseType | boolean {
-        const key = keyListType.getTypes().filter((type) => !(type instanceof LiteralType))[0];
+        const key = keyListType.getTypes().filter((type) => !(derefType(type) instanceof LiteralType))[0];
 
         if (key) {
             return (

test/valid-data-type.test.ts

@@ -88,6 +88,7 @@ describe("valid-data-type", () => {
     it("type-keyof-tuple", assertValidSchema("type-keyof-tuple", "MyType"));
     it("type-keyof-object", assertValidSchema("type-keyof-object", "MyType"));
     it("type-keyof-object-function", assertValidSchema("type-keyof-object-function", "MyType"));
+    it("type-mapped-pick-union-alias", assertValidSchema("type-mapped-pick-union-alias", "PickAliasedLiteralUnion"));
     it("type-mapped-simple", assertValidSchema("type-mapped-simple", "MyObject"));
     it("type-mapped-index", assertValidSchema("type-mapped-index", "MyObject"));
     it("type-mapped-index-as", assertValidSchema("type-mapped-index-as", "MyObject"));

test/valid-data/type-mapped-pick-union-alias/main.ts

@@ -0,0 +1,9 @@
+interface SomeInterface {
+    foo: string;
+    bar: number;
+}
+
+type KeyFoo = "foo";
+type KeyBar = "bar";
+
+export type PickAliasedLiteralUnion = Pick<SomeInterface, KeyFoo | KeyBar>;

test/valid-data/type-mapped-pick-union-alias/schema.json

@@ -0,0 +1,22 @@
+{
+  "$ref": "#/definitions/PickAliasedLiteralUnion",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "PickAliasedLiteralUnion": {
+      "additionalProperties": false,
+      "properties": {
+        "bar": {
+          "type": "number"
+        },
+        "foo": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "foo",
+        "bar"
+      ],
+      "type": "object"
+    }
+  }
+}