SentryUserInteractionWidget checks if the Elements are mounted before comparing them (#1339)

Author: marandaneto

CHANGELOG.md

@@ -12,6 +12,10 @@
   - [changelog](https://github.com/getsentry/sentry-cocoa/blob/main/CHANGELOG.md#831)
   - [diff](https://github.com/getsentry/sentry-cocoa/compare/8.0.0...8.3.1)
 
+### Fixes
+
+- SentryUserInteractionWidget checks if the Elements are mounted before comparing them ([#1339](https://github.com/getsentry/sentry-dart/pull/1339))
+
 ## 7.0.0
 
 ### Features

flutter/lib/src/user_interaction/sentry_user_interaction_widget.dart

@@ -151,8 +151,11 @@ class _SentryUserInteractionWidgetState
     );
 
     final activeTransaction = _activeTransaction;
+    final lastElement = _lastTappedWidget?.element;
     if (activeTransaction != null) {
-      if (_lastTappedWidget?.element.widget == element.widget &&
+      if (_isElementMounted(lastElement) &&
+          _isElementMounted(element) &&
+          lastElement?.widget == element.widget &&
           _lastTappedWidget?.eventType == tappedWidget.eventType &&
           !activeTransaction.finished) {
         // ignore: invalid_use_of_internal_member
@@ -339,4 +342,26 @@ class _SentryUserInteractionWidgetState
 
     return null;
   }
+
+  bool _isElementMounted(Element? element) {
+    if (element == null) {
+      return false;
+    }
+    try {
+      // ignore: return_of_invalid_type
+      return (element as dynamic).mounted;
+    } on NoSuchMethodError catch (_) {
+      // mounted checks if the widget is not null.
+
+      try {
+        // Flutter 3.0.0 does `_widget!` and if `_widget` is null it throws.
+
+        // ignore: unnecessary_null_comparison
+        return element.widget != null;
+      } catch (_) {
+        // if it throws, the `_widget` is null and not mounted.
+        return false;
+      }
+    }
+  }
 }