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 93037822cf3553ca0b60b62b736430b96770520d..d84f2718b41f94e2388054ec6adf0a500daa8c5b 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -2377,6 +2377,9 @@ 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();
@@ -2563,6 +2566,30 @@ 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>();
+  }
+
+  EXCEPTION_PREAMBLE();
+
+  PropertyAttributes attributes;
+  i::MaybeObject* value =
+      receiver->GetProperty(*receiver, lookup, *name, &attributes);
+
+  // If the property being looked up is a callback, it can throw
+  // an exception.
+  has_pending_exception = value->IsFailure();

[Mads Ager (chromium), 2011/01/28 11:39:18]

Should you test for value->IsException instead and assert that it cannot be
OutOfMemory or RetryAfterGC?

[antonm, 2011/01/28 13:37:25]

I can, but not sure if it's a good idea.  Plus technically we can probably have
OOM here if callback is JS thing which exhausts the memory.  I hope that
EXCEPTION_ macros should cope with any kind of failure.

Am I missing something?

+  EXCEPTION_BAILOUT_CHECK(Local<Value>());
+
+  i::Handle<i::Object> result(value->ToObjectUnchecked());
+  return Utils::ToLocal(result);
+}
+
+
 Local<Value> v8::Object::GetRealNamedPropertyInPrototypeChain(
       Handle<String> key) {
   ON_BAILOUT("v8::Object::GetRealNamedPropertyInPrototypeChain()",
@@ -2572,17 +2599,7 @@ 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);
 }
 
 
@@ -2593,17 +2610,7 @@ 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);
 }