♻️ Add a non-crypto fallback for crypto.randomUUID() (#2446)

Author: KATO-Hiro

src/lib/utils/auth_forms.ts

@@ -151,7 +151,7 @@ export const isDevelopmentMode = (): boolean => {
  * Contains constraints and shape definitions used across different form strategies
  */
 const createBaseAuthForm = () => ({
-  id: 'error-fallback-form-' + crypto.randomUUID(), // Generate unique form ID for fallback
+  id: getBaseAuthFormId(),
   data: { username: '', password: '' },
   constraints: {
     username: { minlength: 3, maxlength: 24, required: true, pattern: '[\\w]*' },
@@ -167,3 +167,25 @@ const createBaseAuthForm = () => ({
     password: { type: 'string' },
   },
 });
+
+/**
+ * Generates a unique identifier for authentication form elements.
+ *
+ * Uses Web Crypto API's randomUUID() when available, falling back to a
+ * timestamp-based random string for environments where crypto is unavailable.
+ *
+ * @returns A unique string identifier prefixed with 'error-fallback-form-'
+ *
+ * @example
+ * ```typescript
+ * const formId = getBaseAuthFormId();
+ * // Returns: "error-fallback-form-550e8400-e29b-41d4-a716-446655440000"
+ * // or: "error-fallback-form-1703875200000-abc123def"
+ * ```
+ */
+const getBaseAuthFormId = () => {
+  return (
+    'error-fallback-form-' +
+    (globalThis.crypto?.randomUUID?.() ?? `${Date.now()}-${Math.random().toString(36).slice(2)}`)
+  ); // Fallback when Web Crypto is unavailable
+};

src/test/lib/utils/auth_forms.test.ts

@@ -189,6 +189,19 @@ describe('auth_forms', () => {
       expect(crypto.randomUUID).toHaveBeenCalled();
     });
 
+    test('expect to use fallback ID generation when crypto.randomUUID is unavailable', async () => {
+      // Mock crypto.randomUUID to be undefined
+      vi.stubGlobal('crypto', {
+        randomUUID: undefined,
+      });
+
+      vi.mocked(superValidate).mockRejectedValueOnce(new Error('Primary strategy failed'));
+
+      const result = await createAuthFormWithFallback();
+
+      expect(result.form.id).toMatch(/^error-fallback-form-\d+-[a-z0-9]+$/);
+    });
+
     test('expect to use fallback strategy when primary strategy fails', async () => {
       // Mock superValidate to fail
       vi.mocked(superValidate).mockRejectedValueOnce(new Error('SuperValidate failed'));