src: add consistency check to node_platform.cc

We use the `Isolate*` pointer as the sole identifier for a V8 Isolate. In some environments (e.g. multi-threaded), Isolates may be destroyed and new ones created; then, it may happen that the memory that was previously used for one `Isolate` can be re-used for another `Isolate` after the first one has been disposed of. This check is a little guard against accidentally re-using the same per-Isolate platform data structure in such cases, i.e. making sure (to the degree to which that is possible) that the old `Isolate*` has been properly unregistered before one at the same memory address is added. (It’s not 100 % foolproof because the `uv_loop_t*` pointer value could theoretically be the same as well.) PR-URL: #21156 Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Colin Ihrig <[email protected]>

Author: addaleax

src/node_platform.cc

@@ -141,6 +141,7 @@ void NodePlatform::RegisterIsolate(IsolateData* isolate_data, uv_loop_t* loop){
  Mutex::ScopedLock lock(per_isolate_mutex_);
  std::shared_ptr<PerIsolatePlatformData> existing = per_isolate_[isolate];
 if (existing){
+CHECK_EQ(loop, existing->event_loop());
  existing->ref();
  } else{
  per_isolate_[isolate] =

src/node_platform.h

@@ -72,6 +72,8 @@ class PerIsolatePlatformData :
 boolFlushForegroundTasksInternal();
 voidCancelPendingDelayedTasks();
 
+constuv_loop_t* event_loop() const{return loop_}
+
 private:
 voidDeleteFromScheduledTasks(DelayedTask* task);