Make exception thrown via v8 public API propagate to v8::TryCatch as JS thrown exceptions do.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index abc48ba1a0c160b76147b824de3a61c107dfb52f..0ca1b1af54bd073ca0c37479d3a62cbd19b1c978 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -2383,6 +2383,9 @@ bool v8::Object::SetPrototype(Handle<Value> value) {
   ENTER_V8;
   i::Handle<i::JSObject> self = Utils::OpenHandle(this);
   i::Handle<i::Object> value_obj = Utils::OpenHandle(*value);
+  // We do not allow exceptions thrown while setting the prototype
+  // propagate outside.
+  TryCatch try_catch;
   EXCEPTION_PREAMBLE();
   i::Handle<i::Object> result = i::SetPrototype(self, value_obj);
   has_pending_exception = result.is_null();
@@ -2569,6 +2572,25 @@ bool v8::Object::HasIndexedLookupInterceptor() {
 }
 
 
+static Local<Value> GetPropertyByLookup(i::Handle<i::JSObject> receiver,
+                                        i::Handle<i::String> name,
+                                        i::LookupResult* lookup) {
+  if (!lookup->IsProperty()) {
+    // No real property was found.
+    return Local<Value>();
+  }
+
+  // If the property being looked up is a callback, it can throw
+  // an exception.
+  EXCEPTION_PREAMBLE();
+  i::Handle<i::Object> result = i::GetProperty(receiver, name, lookup);
+  has_pending_exception = result.is_null();
+  EXCEPTION_BAILOUT_CHECK(Local<Value>());
+
+  return Utils::ToLocal(result);
+}
+
+
 Local<Value> v8::Object::GetRealNamedPropertyInPrototypeChain(
       Handle<String> key) {
   ON_BAILOUT("v8::Object::GetRealNamedPropertyInPrototypeChain()",
@@ -2578,17 +2600,7 @@ Local<Value> v8::Object::GetRealNamedPropertyInPrototypeChain(
   i::Handle<i::String> key_obj = Utils::OpenHandle(*key);
   i::LookupResult lookup;
   self_obj->LookupRealNamedPropertyInPrototypes(*key_obj, &lookup);
-  if (lookup.IsProperty()) {
-    PropertyAttributes attributes;
-    i::Object* property =
-        self_obj->GetProperty(*self_obj,
-                              &lookup,
-                              *key_obj,
-                              &attributes)->ToObjectUnchecked();
-    i::Handle<i::Object> result(property);
-    return Utils::ToLocal(result);
-  }
-  return Local<Value>();  // No real property was found in prototype chain.
+  return GetPropertyByLookup(self_obj, key_obj, &lookup);
 }
 
 
@@ -2599,17 +2611,7 @@ Local<Value> v8::Object::GetRealNamedProperty(Handle<String> key) {
   i::Handle<i::String> key_obj = Utils::OpenHandle(*key);
   i::LookupResult lookup;
   self_obj->LookupRealNamedProperty(*key_obj, &lookup);
-  if (lookup.IsProperty()) {
-    PropertyAttributes attributes;
-    i::Object* property =
-        self_obj->GetProperty(*self_obj,
-                              &lookup,
-                              *key_obj,
-                              &attributes)->ToObjectUnchecked();
-    i::Handle<i::Object> result(property);
-    return Utils::ToLocal(result);
-  }
-  return Local<Value>();  // No real property was found in prototype chain.
+  return GetPropertyByLookup(self_obj, key_obj, &lookup);
 }