fix: "Unexpected code branch" error when type is a union that includes 'symbol' (#2282)

Author: alexchexes

src/TypeFormatter/PrimitiveUnionTypeFormatter.ts

@@ -6,7 +6,6 @@ import type { BaseType } from "../Type/BaseType.js";
 import { BooleanType } from "../Type/BooleanType.js";
 import { NullType } from "../Type/NullType.js";
 import { NumberType } from "../Type/NumberType.js";
-import { PrimitiveType } from "../Type/PrimitiveType.js";
 import { StringType } from "../Type/StringType.js";
 import { UnionType } from "../Type/UnionType.js";
 import { uniqueArray } from "../Utils/uniqueArray.js";
@@ -25,7 +24,15 @@ export class PrimitiveUnionTypeFormatter implements SubTypeFormatter {
     }
 
     protected isPrimitiveUnion(type: UnionType): boolean {
-        return type.getTypes().every((item) => item instanceof PrimitiveType);
+        return type
+            .getTypes()
+            .every(
+                (item) =>
+                    item instanceof StringType ||
+                    item instanceof NumberType ||
+                    item instanceof BooleanType ||
+                    item instanceof NullType,
+            );
     }
 
     protected getPrimitiveType(item: BaseType): RawTypeName {

test/valid-data-other.test.ts

@@ -76,6 +76,7 @@ describe("valid-data-other", () => {
 
     it("symbol", assertValidSchema("symbol", "MyObject"));
     it("unique-symbol", assertValidSchema("unique-symbol", "MyObject"));
+    it("symbol-union", assertValidSchema("symbol-union", "MyType"));
 
     it("array-min-items-1", assertValidSchema("array-min-items-1", "MyType"));
     it("array-min-items-2", assertValidSchema("array-min-items-2", "MyType"));

test/valid-data/symbol-union/main.ts

@@ -0,0 +1 @@
+export type MyType = string | symbol;

test/valid-data/symbol-union/schema.json

@@ -0,0 +1,14 @@
+{
+  "$ref": "#/definitions/MyType",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "MyType": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {}
+      ]
+    }
+  }
+}