v8::String::Concat must not throw.

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 724 matching lines @@
     CcTest::heap()->CollectGarbage(i::NEW_SPACE);  // in old gen now
     i::Handle<i::String> isymbol =
         factory->InternalizeString(istring);
     CHECK(isymbol->IsInternalizedString());
   }
   CcTest::heap()->CollectAllGarbage(i::Heap::kNoGCFlags);
   CcTest::heap()->CollectAllGarbage(i::Heap::kNoGCFlags);
 }
 
 
-class DummyResource : public v8::String::ExternalStringResource {
+class RandomLengthResource : public v8::String::ExternalStringResource {
  public:
+  explicit RandomLengthResource(int length) : length_(length) {}
   virtual const uint16_t* data() const { return string_; }
-  virtual size_t length() const { return 1 << 30; }
+  virtual size_t length() const { return length_; }
 
  private:
   uint16_t string_[10];
+  int length_;
 };
 
 
-class DummyOneByteResource : public v8::String::ExternalOneByteStringResource {
+class RandomLengthOneByteResource
+    : public v8::String::ExternalOneByteStringResource {
  public:
+  explicit RandomLengthOneByteResource(int length) : length_(length) {}
   virtual const char* data() const { return string_; }
-  virtual size_t length() const { return 1 << 30; }
+  virtual size_t length() const { return length_; }
 
  private:
   char string_[10];
+  int length_;
 };
 
 
 THREADED_TEST(NewExternalForVeryLongString) {
   {
     LocalContext env;
     v8::HandleScope scope(env->GetIsolate());
     v8::TryCatch try_catch;
-    DummyOneByteResource r;
+    RandomLengthOneByteResource r(1 << 30);
     v8::Local<v8::String> str = v8::String::NewExternal(CcTest::isolate(), &r);
     CHECK(str.IsEmpty());
     CHECK(try_catch.HasCaught());
     String::Utf8Value exception_value(try_catch.Exception());
     CHECK_EQ("RangeError: Invalid string length", *exception_value);
   }
 
   {
     LocalContext env;
     v8::HandleScope scope(env->GetIsolate());
     v8::TryCatch try_catch;
-    DummyResource r;
+    RandomLengthResource r(1 << 30);
     v8::Local<v8::String> str = v8::String::NewExternal(CcTest::isolate(), &r);
     CHECK(str.IsEmpty());
     CHECK(try_catch.HasCaught());
     String::Utf8Value exception_value(try_catch.Exception());
     CHECK_EQ("RangeError: Invalid string length", *exception_value);
   }
 }
 
 
 THREADED_TEST(ScavengeExternalString) {
@@ skipping 23432 matching lines @@
 }
 
 
 TEST(InvalidCacheData) {
   v8::V8::Initialize();
   v8::HandleScope scope(CcTest::isolate());
   LocalContext context;
   TestInvalidCacheData(v8::ScriptCompiler::kConsumeParserCache);
   TestInvalidCacheData(v8::ScriptCompiler::kConsumeCodeCache);
 }
+
+
+TEST(StringConcatOverflow) {
+  v8::V8::Initialize();
+  v8::HandleScope scope(CcTest::isolate());
+  RandomLengthOneByteResource* r =
+      new RandomLengthOneByteResource(i::String::kMaxLength);
+  v8::Local<v8::String> str = v8::String::NewExternal(CcTest::isolate(), r);
+  CHECK(!str.IsEmpty());
+  v8::TryCatch try_catch;
+  v8::Local<v8::String> result = v8::String::Concat(str, str);
+  CHECK(result.IsEmpty());
+  CHECK(!try_catch.HasCaught());
+}