Guard against non-function exports in wrapServerFunction

Author: onurtemizkan

packages/react-router/src/server/rsc/wrapServerFunction.ts

@@ -41,6 +41,12 @@ export function wrapServerFunction<T extends (...args: any[]) => Promise<any>>(
   serverFunction: T,
   options: WrapServerFunctionOptions = {},
 ): T {
+  // Auto-instrumentation wraps all exports from "use server" files, including non-function values.
+  if (typeof serverFunction !== 'function') {
+    DEBUG_BUILD && debug.warn(`[RSC] Not wrapping non-function export: ${functionName}`);
+    return serverFunction;
+  }
+
   DEBUG_BUILD && debug.log(`[RSC] Wrapping server function: ${functionName}`);
 
   return new Proxy(serverFunction, {

packages/react-router/test/server/rsc/wrapServerFunction.test.ts

@@ -186,4 +186,16 @@ describe('wrapServerFunction', () => {
 
     await expect(wrappedFn()).rejects.toBe(mockError);
   });
+
+  describe('non-function exports', () => {
+    it('should return non-function values unchanged', () => {
+      expect(wrapServerFunction('foo', 3 as any)).toBe(3);
+      expect(wrapServerFunction('foo', null as any)).toBe(null);
+    });
+
+    it('should return object as-is', () => {
+      const obj = { key: 'value' };
+      expect(wrapServerFunction('foo', obj as any)).toBe(obj);
+    });
+  });
 });