fix: load admin assets from stable paths

backend/bot/app/web/webapp/assets.py

@@ -1372,10 +1372,10 @@ def _resolve_webapp_js_asset_name() -> str:
 
 
 def _resolve_webapp_admin_js_asset_name() -> str:
-    return _resolve_hashed_js_asset_name(
+    # The admin bundle is lazy-loaded from the already running Mini App. In
-        kind="admin-js",
+    # deployments where nginx serves static files in front of aiohttp, stale
-        base_name="subscription_webapp_admin",
+    # hashed admin filenames can 404 even though the runtime build asset exists.
-    )
+    return _set_cached_asset_name("admin-js", "subscription_webapp_admin.js")
 
 
 def _resolve_hashed_js_asset_name(*, kind: str, base_name: str) -> str:
@@ -1405,10 +1405,9 @@ def _resolve_webapp_css_asset_name() -> str:
 
 
 def _resolve_webapp_admin_css_asset_name() -> str:
-    return _resolve_hashed_css_asset_name(
+    # Keep the lazy-loaded admin stylesheet on the stable build filename for
-        kind="admin-css",
+    # the same reason as the JS bundle above.
-        base_name="subscription_webapp_admin",
+    return _set_cached_asset_name("admin-css", "subscription_webapp_admin.css")
-    )
 
 
 def _resolve_hashed_css_asset_name(*, kind: str, base_name: str) -> str:

frontend/src/App.svelte

@@ -635,7 +635,10 @@
       link.rel = "stylesheet";
       link.href = href;
       link.onload = () => resolve();
-      link.onerror = () => reject(new Error(`stylesheet_load_failed:${href}`));
+      link.onerror = () => {
+        link.remove();
+        reject(new Error(`stylesheet_load_failed:${href}`));
+      };
       document.head.appendChild(link);
     });
   }
@@ -648,11 +651,34 @@
       script.src = src;
       script.async = true;
       script.onload = () => resolve();
-      script.onerror = () => reject(new Error(`script_load_failed:${src}`));
+      script.onerror = () => {
+        script.remove();
+        reject(new Error(`script_load_failed:${src}`));
+      };
       document.head.appendChild(script);
     });
   }
 
+  async function appendStylesheetWithFallback(id, href, fallbackName) {
+    const fallbackHref = resolveWebappAssetPath("", fallbackName);
+    try {
+      await appendStylesheetOnce(id, href);
+    } catch (error) {
+      if (!fallbackHref || href === fallbackHref) throw error;
+      await appendStylesheetOnce(id, fallbackHref);
+    }
+  }
+
+  async function appendScriptWithFallback(id, src, fallbackName) {
+    const fallbackSrc = resolveWebappAssetPath("", fallbackName);
+    try {
+      await appendScriptOnce(id, src);
+    } catch (error) {
+      if (!fallbackSrc || src === fallbackSrc) throw error;
+      await appendScriptOnce(id, fallbackSrc);
+    }
+  }
+
   function readAdminBundleApi() {
     const bundle = window.SubscriptionWebAppAdmin;
     return bundle?.mount ? bundle : null;
@@ -672,8 +698,16 @@
     adminBundlePromise = (async () => {
       const cssHref = resolveWebappAssetPath(CFG.adminCssAsset, "subscription_webapp_admin.css");
       const jsSrc = resolveWebappAssetPath(CFG.adminJsAsset, "subscription_webapp_admin.js");
-      await appendStylesheetOnce("subscription-webapp-admin-css", cssHref);
+      await appendStylesheetWithFallback(
-      await appendScriptOnce("subscription-webapp-admin-js", jsSrc);
+        "subscription-webapp-admin-css",
+        cssHref,
+        "subscription_webapp_admin.css",
+      );
+      await appendScriptWithFallback(
+        "subscription-webapp-admin-js",
+        jsSrc,
+        "subscription_webapp_admin.js",
+      );
       const loaded = readAdminBundleApi();
       if (!loaded) throw new Error("admin_bundle_missing_mount");
       adminBundleApi = loaded;

tests/test_webapp_assets.py

@@ -488,7 +488,7 @@ class WebAppAssetTests(unittest.IsolatedAsyncioTestCase):
                     "subscription_webapp.min.22222222.js",
                 )
 
-    def test_resolve_webapp_admin_asset_names_prefer_latest_minified_builds(self):
+    def test_resolve_webapp_admin_asset_names_use_stable_runtime_builds(self):
         with tempfile.TemporaryDirectory() as tmpdir:
             asset_dir = Path(tmpdir)
             (asset_dir / "subscription_webapp_admin.js").write_text(
@@ -513,11 +513,11 @@ class WebAppAssetTests(unittest.IsolatedAsyncioTestCase):
             with patch.object(webapp_assets, "ASSET_DIR", asset_dir):
                 self.assertEqual(
                     subscription_webapp._resolve_webapp_admin_js_asset_name(),
-                    "subscription_webapp_admin.min.22222222.js",
+                    "subscription_webapp_admin.js",
                 )
                 self.assertEqual(
                     subscription_webapp._resolve_webapp_admin_css_asset_name(),
-                    "subscription_webapp_admin.22222222.css",
+                    "subscription_webapp_admin.css",
                 )
 
     async def test_js_asset_route_sets_immutable_cache_control_for_minified_asset(self):