Fix for bug 23484 (obscure error when a compilation error happens during Object::Init())

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
@@ skipping 1283 matching lines @@
 DART_EXPORT Dart_Isolate Dart_CreateIsolate(const char* script_uri,
                                             const char* main,
                                             const uint8_t* snapshot,
                                             void* callback_data,
                                             char** error) {
   CHECK_NO_ISOLATE(Isolate::Current());
   char* isolate_name = BuildIsolateName(script_uri, main);
   Thread::EnsureInit();
   Isolate* isolate = Dart::CreateIsolate(isolate_name);
   free(isolate_name);
-  {
-    StackZone zone(isolate);
-    HANDLESCOPE(isolate);
-    const Error& error_obj =
-        Error::Handle(isolate,
-                      Dart::InitializeIsolate(snapshot, callback_data));
-    if (error_obj.IsNull()) {
+  StackZone zone(isolate);
+  HANDLESCOPE(isolate);
+  // We enter an API scope here as InitializeIsolate could compile some
+  // bootstrap library files which call out to a tag handler that may create
+  // Api Handles when an error is encountered.
+  Dart_EnterScope();
+  const Error& error_obj =
+      Error::Handle(isolate, Dart::InitializeIsolate(snapshot, callback_data));
+  if (error_obj.IsNull()) {
 #if defined(DART_NO_SNAPSHOT)
-      if (FLAG_check_function_fingerprints) {
-        Library::CheckFunctionFingerprints();
-      }
+    if (FLAG_check_function_fingerprints) {
+      Library::CheckFunctionFingerprints();
+    }
 #endif  // defined(DART_NO_SNAPSHOT).
-      START_TIMER(isolate, time_total_runtime);
-      return Api::CastIsolate(isolate);
-    }
-    *error = strdup(error_obj.ToErrorCString());
+    // We exit the API scope entered above.
+    Dart_ExitScope();
+    START_TIMER(isolate, time_total_runtime);
+    return Api::CastIsolate(isolate);
   }
+  *error = strdup(error_obj.ToErrorCString());
+  // We exit the API scope entered above.
+  Dart_ExitScope();
   Dart::ShutdownIsolate();
   return DART_ILLEGAL_ISOLATE;
 }
 
 
 DART_EXPORT void Dart_ShutdownIsolate() {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
   {
     StackZone zone(isolate);
@@ skipping 4251 matching lines @@
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart