fix(performance): Missing frames measurements when active span is trimmed (#3684)

Author: krystofwoldrich

CHANGELOG.md

@@ -42,6 +42,7 @@
 ### Fixes
 
 - Allow custom `sentryUrl` for Expo updates source maps uploads ([#3664](https://github.com/getsentry/sentry-react-native/pull/3664))
+- Missing Mobile Vitals (slow, frozen frames) when ActiveSpan (Transaction) is trimmed at the end ([#3684](https://github.com/getsentry/sentry-react-native/pull/3684))
 
 ## 5.19.3
 

src/js/tracing/utils.ts

@@ -78,6 +78,15 @@ export function instrumentChildSpanFinish(
 
         callback(span, endTimestamp);
       };
+
+      // eslint-disable-next-line @typescript-eslint/unbound-method
+      const originalSpanEnd = span.end;
+
+      span.end = (endTimestamp?: number) => {
+        originalSpanEnd.apply(span, [endTimestamp]);
+
+        callback(span, endTimestamp);
+      };
     };
   }
 }