Back out "Do not hold raw RuntimeScheduler pointer in BufferedRuntime…

…Executor"

Summary:
A crash we are getting in the wild suggests that destruction on weak ref count going away may be delaying RuntimeExecutor task destruction to a point where jsi::Function is invalid. Let's try backing D62748768 out and seeing if the crash goes away.

Changelog:
[General][Fixed] - Attempt to fix crash from delayed RuntimeExecutor task destruction

#bypass-github-export-checks

Reviewed By: mdvacca

Differential Revision: D63568504

fbshipit-source-id: 6152e7293902d0eb67a14c5840bea56561c35b08

packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp

@@ -137,7 +137,7 @@ ReactInstance::ReactInstance(
       PerformanceEntryReporter::getInstance().get());
 
   bufferedRuntimeExecutor_ = std::make_shared<BufferedRuntimeExecutor>(
-      [runtimeScheduler = runtimeScheduler_](
+      [runtimeScheduler = runtimeScheduler_.get()](
           std::function<void(jsi::Runtime & runtime)>&& callback) {
         runtimeScheduler->scheduleWork(std::move(callback));
       });
@@ -156,7 +156,7 @@ void ReactInstance::unregisterFromInspector() {
 }
 
 RuntimeExecutor ReactInstance::getUnbufferedRuntimeExecutor() noexcept {
-  return [runtimeScheduler = runtimeScheduler_](
+  return [runtimeScheduler = runtimeScheduler_.get()](
              std::function<void(jsi::Runtime & runtime)>&& callback) {
     runtimeScheduler->scheduleWork(std::move(callback));
   };
@@ -167,14 +167,12 @@ RuntimeExecutor ReactInstance::getUnbufferedRuntimeExecutor() noexcept {
 // getUnbufferedRuntimeExecutor() instead if you do not need the main JS bundle
 // to have finished. e.g. setting global variables into JS runtime.
 RuntimeExecutor ReactInstance::getBufferedRuntimeExecutor() noexcept {
-  // FIXME: we don't really need a weak reference here, bufferedRuntimeExecutor
-  // retains a strong reference to runtimeScheduler, which in turns retains weak
-  // references to the runtime
-  return [weakBufferedRuntimeExecutor =
+  return [weakBufferedRuntimeExecutor_ =
               std::weak_ptr<BufferedRuntimeExecutor>(bufferedRuntimeExecutor_)](
              std::function<void(jsi::Runtime & runtime)>&& callback) {
-    if (auto bufferedRuntimeExecutor = weakBufferedRuntimeExecutor.lock()) {
-      bufferedRuntimeExecutor->execute(std::move(callback));
+    if (auto strongBufferedRuntimeExecutor_ =
+            weakBufferedRuntimeExecutor_.lock()) {
+      strongBufferedRuntimeExecutor_->execute(std::move(callback));
     }
   };
 }
@@ -211,8 +209,12 @@ void ReactInstance::loadScript(
   std::string scriptName = simpleBasename(sourceURL);
 
   runtimeScheduler_->scheduleWork(
-      [this, scriptName, sourceURL, buffer = std::move(buffer)](
-          jsi::Runtime& runtime) {
+      [this,
+       scriptName,
+       sourceURL,
+       buffer = std::move(buffer),
+       weakBufferedRuntimeExecuter = std::weak_ptr<BufferedRuntimeExecutor>(
+           bufferedRuntimeExecutor_)](jsi::Runtime& runtime) {
         SystraceSection s("ReactInstance::loadScript");
         bool hasLogger(ReactMarker::logTaggedMarkerBridgelessImpl);
         if (hasLogger) {
@@ -238,8 +240,10 @@ void ReactInstance::loadScript(
               ReactMarker::INIT_REACT_RUNTIME_STOP);
           ReactMarker::logMarkerBridgeless(ReactMarker::APP_STARTUP_STOP);
         }
-
-        bufferedRuntimeExecutor_->flush();
+        if (auto strongBufferedRuntimeExecuter =
+                weakBufferedRuntimeExecuter.lock()) {
+          strongBufferedRuntimeExecuter->flush();
+        }
       });
 }