Correct handling of unions of unions

Resolves #2469

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### Bug Fixes
 
 -   Fixed an issue where a namespace would not be created for merged function-namespaces only containing types, #2476.
+-   Fixed an infinite loop when converting a union type which directly contained another union type which refers to itself, #2469.
 
 ## v0.25.6 (2024-01-01)
 

src/lib/converter/types.ts

@@ -136,12 +136,7 @@ export function convertType(
     // We need to check it here, not just in the union checker, because typeToTypeNode
     // will use the origin when serializing
     // aliasSymbol check is important - #2468
-    if (
-        typeOrNode.isUnion() &&
-        typeOrNode.origin &&
-        !typeOrNode.origin.isUnion() &&
-        !typeOrNode.aliasSymbol
-    ) {
+    if (typeOrNode.isUnion() && typeOrNode.origin && !typeOrNode.aliasSymbol) {
         return convertType(context, typeOrNode.origin);
     }
 

src/test/TestLogger.ts

@@ -32,6 +32,17 @@ export class TestLogger extends Logger {
         this.messages.splice(index, 1);
     }
 
+    expectNoMessage(message: string) {
+        const regex = createRegex(message);
+        const index = this.messages.findIndex((m) => regex.test(m));
+        if (index !== -1) {
+            const messages = this.messages.join("\n\t");
+            fail(
+                `Expected "${message}" to not be logged. The logged messages were:\n\t${messages}`,
+            );
+        }
+    }
+
     expectNoOtherMessages({ ignoreDebug } = { ignoreDebug: true }) {
         const messages = ignoreDebug
             ? this.messages.filter((msg) => !msg.startsWith("debug"))

src/test/behavior.c2.test.ts

@@ -1086,12 +1086,15 @@ describe("Behavior Tests", () => {
         logger.expectNoOtherMessages();
     });
 
-    it("Should not produce warnings when processing an object type twice due to intersection", () => {
+    it("Should not warn about recursive types", () => {
         const project = convert("refusingToRecurse");
         const schemaTypeBased = query(project, "schemaTypeBased");
         equal(schemaTypeBased.type?.toString(), "Object & Object");
+        equal(
+            querySig(project, "Map.getFilter").type?.toString(),
+            "void | ExpressionSpecification",
+        );
 
-        logger.expectMessage("debug: Begin readme.md*");
-        logger.expectNoOtherMessages({ ignoreDebug: false });
+        logger.expectNoMessage("debug: Refusing to recurse*");
     });
 });

src/test/converter2/behavior/refusingToRecurse.ts

@@ -27,3 +27,17 @@ export const schema = {
 export type Schema = FromSchema<typeof schema>;
 
 export const schemaTypeBased = null! as Schema;
+
+export type ExpressionSpecification =
+    | ["array", unknown | ExpressionSpecification]
+    | [
+          "array",
+          string | ExpressionSpecification,
+          unknown | ExpressionSpecification,
+      ];
+
+export class Map {
+    getFilter(layerId: string): ExpressionSpecification | void {
+        return;
+    }
+}