From 5b0a01a02a82fd6b2c6e043f67330ac77b364f7f Mon Sep 17 00:00:00 2001
From: Cursor Agent <cursoragent@cursor.com>
Date: Wed, 17 Jun 2026 11:07:11 +0000
Subject: [PATCH] fix(cdn): reject manifests missing artifacts before cache
 wipe

Background CDN refresh called _rebuildFromRoot() which cleared all
in-memory definitions before checking for an artifacts section. A
transient or bad deploy returning parseable JSON without artifacts
(e.g. {}) wiped the working session and could persist the unusable
manifest via _saveCachedState.

Validate the artifacts section exists before mutating cache state so
failed refreshes keep the last good definitions.

Co-authored-by: Sharjeel Yunus <sharjeelyunus@users.noreply.github.com>
---
 .../definition_providers/cdn_provider.dart       | 11 +++++++++--
 modules/ensemble/test/cdn_provider_test.dart     | 16 ++++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/modules/ensemble/lib/framework/definition_providers/cdn_provider.dart b/modules/ensemble/lib/framework/definition_providers/cdn_provider.dart
index c55536fb7..7f9d43850 100644
--- a/modules/ensemble/lib/framework/definition_providers/cdn_provider.dart
+++ b/modules/ensemble/lib/framework/definition_providers/cdn_provider.dart
@@ -720,6 +720,14 @@ class CdnDefinitionProvider extends DefinitionProvider {
   // --------------------------------------------------------
 
   void _rebuildFromRoot(Map<String, dynamic> root) {
+    // Validate before mutating in-memory or persisted cache. A background
+    // refresh that clears first and then bails on missing artifacts would
+    // otherwise wipe a working session and persist an unusable manifest.
+    if (_asMap(root['artifacts']) == null) {
+      throw ConfigError(
+          'CDN manifest is missing a valid artifacts section.');
+    }
+
     // reset caches/state
     _artifactCache.clear();
     _screenNameMappings.clear();
@@ -729,8 +737,7 @@ class CdnDefinitionProvider extends DefinitionProvider {
     _appConfig = null;
     _applySecretsFromRoot(root);
 
-    final artifacts = _asMap(root['artifacts']);
-    if (artifacts == null) return;
+    final artifacts = _asMap(root['artifacts'])!;
 
     // 1) config
     final configMap = _asMap(artifacts['config']);
diff --git a/modules/ensemble/test/cdn_provider_test.dart b/modules/ensemble/test/cdn_provider_test.dart
index 3b855f166..f859bbcbc 100644
--- a/modules/ensemble/test/cdn_provider_test.dart
+++ b/modules/ensemble/test/cdn_provider_test.dart
@@ -3,6 +3,7 @@ import 'dart:ui';
 import 'package:ensemble/ensemble.dart';
 import 'package:ensemble/framework/definition_providers/cdn_provider.dart';
 import 'package:ensemble/framework/definition_providers/provider.dart';
+import 'package:ensemble/framework/error_handling.dart';
 import 'package:ensemble/util/utils.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_i18n/flutter_i18n.dart';
@@ -121,6 +122,21 @@ void main() {
       final prefs = await SharedPreferences.getInstance();
       expect(prefs.getStringList(cacheKey), isNull);
     });
+
+    test('rejects manifest without artifacts before mutating in-memory cache',
+        () async {
+      final provider = CdnDefinitionProvider('missing-artifacts-app');
+      await provider.applyRuntimeManifestForTesting(_manifestWithNewKey());
+
+      expect(provider.getSupportedLanguages(), isNotEmpty);
+
+      expect(
+        () => provider.rebuildManifestCacheForTesting({}),
+        throwsA(isA<ConfigError>()),
+      );
+
+      expect(provider.getSupportedLanguages(), isNotEmpty);
+    });
   });
 
   group('CDN translation runtime refresh', () {