V8 API: Add a missing NULL check into Isolate::GetCurrentContext().

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 14297 matching lines @@
 static v8::Handle<Value> GetCallingContextCallback(const v8::Arguments& args) {
   ApiTestFuzzer::Fuzz();
   CHECK(Context::GetCurrent() == calling_context0);
   CHECK(args.GetIsolate()->GetCurrentContext() == calling_context0);
   CHECK(Context::GetCalling() == calling_context1);
   CHECK(Context::GetEntered() == calling_context2);
   return v8::Integer::New(42);
 }
 
 
+THREADED_TEST(GetCurrentContextWhenNotInContext) {
+  i::Isolate* isolate = i::Isolate::Current();
+  CHECK(isolate != NULL);
+  CHECK(isolate->context() == NULL);
+  v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
+  v8::HandleScope scope(v8_isolate);
+  // The following should not crash, but return an empty handle.
+  v8::Local<v8::Context> current = v8_isolate->GetCurrentContext();
+  CHECK(current.IsEmpty());
+}
+
+
 THREADED_TEST(GetCallingContext) {
   v8::Isolate* isolate = v8::Isolate::GetCurrent();
   v8::HandleScope scope(isolate);
 
   Local<Context> calling_context0(Context::New(isolate));
   Local<Context> calling_context1(Context::New(isolate));
   Local<Context> calling_context2(Context::New(isolate));
   ::calling_context0 = calling_context0;
   ::calling_context1 = calling_context1;
   ::calling_context2 = calling_context2;
@@ skipping 5125 matching lines @@
   i::Semaphore* sem_;
   volatile int sem_value_;
 };
 
 
 THREADED_TEST(SemaphoreInterruption) {
   ThreadInterruptTest().RunTest();
 }
 
 #endif  // WIN32