Fix for #4150: crash when closing Electron app with custom sync error…

… handler (#4237)

This follows the pattern from d4d6eab to prevent destruction of the functor

CHANGELOG.md

@@ -7,6 +7,7 @@ x.x.x Release notes (yyyy-MM-dd)
 ### Fixed
 * Opening a Realm with a schema that has an orphaned embedded object type performed an extra empty write transaction. ([realm/realm-core#5115](https://github.com/realm/realm-core/pull/5115), since v10.5.0)
 * Schema validation was missing for embedded objects in sets, resulting in an unhelpful error being thrown if the user attempted to define one. ([realm/realm-core#5115](https://github.com/realm/realm-core/pull/5115))
+* Fixed a crash when closing an Electron app with a custom sync error handler ([#4150](https://github.com/realm/realm-js/issues/4150)
 
 ### Compatibility
 * Removed `deprecated-react-native-listview` from root package.json

src/js_sync.hpp

@@ -242,6 +242,11 @@ class SyncSessionErrorHandlerFunctor {
         : m_ctx(Context<T>::get_global_context(ctx))
         , m_func(ctx, error_func)
     {
+#if defined(REALM_PLATFORM_NODE)
+        // Suppressing destruct prevents a crash when closing an Electron app with a
+        // custom sync error handler: https://github.com/realm/realm-js/issues/4150
+        m_func.SuppressDestruct();
+#endif
     }
 
     typename T::Function func() const
@@ -289,7 +294,7 @@ class SyncSessionErrorHandlerFunctor {
 
 private:
     const Protected<typename T::GlobalContext> m_ctx;
-    const Protected<typename T::Function> m_func;
+    Protected<typename T::Function> m_func;
 };