src: guard slightly costly check in MakeCallback more strongly

PR-URL: #41331
Reviewed-By: Gerhard Stöbich <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>
Reviewed-By: Darshan Sen <[email protected]>

Author: addaleax

src/api/callback.cc

@@ -64,10 +64,17 @@ InternalCallbackScope::InternalCallbackScope(Environment* env,
   Isolate* isolate = env->isolate();
 
   HandleScope handle_scope(isolate);
-  // If you hit this assertion, you forgot to enter the v8::Context first.
-  CHECK_EQ(Environment::GetCurrent(isolate), env);
+  Local<Context> current_context = isolate->GetCurrentContext();
+  // If you hit this assertion, the caller forgot to enter the right Node.js
+  // Environment's v8::Context first.
+  // We first check `env->context() != current_context` because the contexts
+  // likely *are* the same, in which case we can skip the slightly more
+  // expensive Environment::GetCurrent() call.
+  if (UNLIKELY(env->context() != current_context)) {
+    CHECK_EQ(Environment::GetCurrent(isolate), env);
+  }
 
-  env->isolate()->SetIdle(false);
+  isolate->SetIdle(false);
 
   env->async_hooks()->push_async_context(
     async_context_.async_id, async_context_.trigger_async_id, object);