Fix TryCatch.ReThrow() to not clobber Message.

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
===================================================================
--- test/cctest/test-api.cc	(revision 14909)
+++ test/cctest/test-api.cc	(working copy)
@@ -4322,6 +4322,37 @@
 }
 
 
+v8::Handle<Value> TryCatchNestedSyntaxHelper(const v8::Arguments& args) {
+  ApiTestFuzzer::Fuzz();
+  v8::TryCatch try_catch;
+  v8::ScriptOrigin origin(v8::String::New("inner"),
+                          v8::Integer::New(1), v8::Integer::New(1));
+  v8::Script::Compile(v8::String::New("invalid ?= 1;\n"), &origin);
+  CHECK(try_catch.HasCaught());
+  return try_catch.ReThrow();
+}
+
+
+// This test ensures that an outer TryCatch in the following situation:
+//   C++/TryCatch -> JS -> C++/TryCatch -> JS w/ SyntaxError
+// does clobber the Message object generated for the inner TryCatch.
+// This exercises the ability of TryCatch.ReThrow() to restore the
+// inner pending Message before throwing the exception again.
+TEST(TryCatchNestedSyntax) {
+  v8::HandleScope scope(v8::Isolate::GetCurrent());
+  v8::V8::Initialize();
+  v8::TryCatch try_catch;
+  Local<ObjectTemplate> templ = ObjectTemplate::New();
+  templ->Set(v8_str("TryCatchNestedSyntaxHelper"),
+             v8::FunctionTemplate::New(TryCatchNestedSyntaxHelper));
+  LocalContext context(0, templ);
+  CompileRunWithOrigin("TryCatchNestedSyntaxHelper();\n", "outer", 1, 1);
+  CHECK(try_catch.HasCaught());
+  Handle<Value> resource = try_catch.Message()->GetScriptResourceName();
+  CHECK_EQ(0, strcmp(*v8::String::Utf8Value(resource), "inner"));
+}
+
+
 THREADED_TEST(Equality) {
   LocalContext context;
   v8::Isolate* isolate = context->GetIsolate();