LibJS: Throw if the trap result of OwnPropertyKeys contains duplicates

4 files changed, 21 insertions, 11 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/AbstractOperations.cpp b/Userland/Libraries/LibJS/Runtime/AbstractOperations.cpp
index cfa0d90eaf..e5671eadef 100644
--- a/Userland/Libraries/LibJS/Runtime/AbstractOperations.cpp
+++ b/Userland/Libraries/LibJS/Runtime/AbstractOperations.cpp
@@ -57,7 +57,7 @@ size_t length_of_array_like(GlobalObject& global_object, Object const& object)
 }
 
 // 7.3.19 CreateListFromArrayLike ( obj [ , elementTypes ] ), https://tc39.es/ecma262/#sec-createlistfromarraylike
-MarkedValueList create_list_from_array_like(GlobalObject& global_object, Value value, Function<Result<void, ErrorType>(Value)> check_value)
+MarkedValueList create_list_from_array_like(GlobalObject& global_object, Value value, Function<void(Value)> check_value)
 {
     auto& vm = global_object.vm();
     auto& heap = global_object.heap();
@@ -76,11 +76,9 @@ MarkedValueList create_list_from_array_like(GlobalObject& global_object, Value v
         if (vm.exception())
             return MarkedValueList { heap };
         if (check_value) {
-            auto result = check_value(next);
-            if (result.is_error()) {
-                vm.throw_exception<TypeError>(global_object, result.release_error());
+            check_value(next);
+            if (vm.exception())
                 return MarkedValueList { heap };
-            }
         }
         list.append(next);
     }
diff --git a/Userland/Libraries/LibJS/Runtime/AbstractOperations.h b/Userland/Libraries/LibJS/Runtime/AbstractOperations.h
index f70f51654b..1be5683d3e 100644
--- a/Userland/Libraries/LibJS/Runtime/AbstractOperations.h
+++ b/Userland/Libraries/LibJS/Runtime/AbstractOperations.h
@@ -21,7 +21,7 @@ Object* get_super_constructor(VM&);
 Reference make_super_property_reference(GlobalObject&, Value actual_this, StringOrSymbol const& property_key, bool strict);
 Value require_object_coercible(GlobalObject&, Value);
 size_t length_of_array_like(GlobalObject&, Object const&);
-MarkedValueList create_list_from_array_like(GlobalObject&, Value, Function<Result<void, ErrorType>(Value)> = {});
+MarkedValueList create_list_from_array_like(GlobalObject&, Value, Function<void(Value)> = {});
 FunctionObject* species_constructor(GlobalObject&, Object const&, FunctionObject& default_constructor);
 GlobalObject* get_function_realm(GlobalObject&, FunctionObject const&);
 bool is_compatible_property_descriptor(bool extensible, PropertyDescriptor const&, Optional<PropertyDescriptor> const& current);
diff --git a/Userland/Libraries/LibJS/Runtime/ErrorTypes.h b/Userland/Libraries/LibJS/Runtime/ErrorTypes.h
index 12acdf9988..fb374a8f13 100644
--- a/Userland/Libraries/LibJS/Runtime/ErrorTypes.h
+++ b/Userland/Libraries/LibJS/Runtime/ErrorTypes.h
@@ -132,6 +132,8 @@
                                "return value must match the target's extensibility")                                                    \
     M(ProxyOwnPropertyKeysNotStringOrSymbol, "Proxy handler's ownKeys trap violates invariant: "                                        \
                                              "the type of each result list element is either String or Symbol")                         \
+    M(ProxyOwnPropertyKeysDuplicates, "Proxy handler's ownKeys trap violates invariant: "                                               \
+                                      "the result list may not contain duplicate elements")                                             \
     M(ProxyPreventExtensionsReturn, "Proxy handler's preventExtensions trap violates "                                                  \
                                     "invariant: cannot return true if the target object is extensible")                                 \
     M(ProxyRevoked, "An operation was performed on a revoked Proxy object")                                                             \
diff --git a/Userland/Libraries/LibJS/Runtime/ProxyObject.cpp b/Userland/Libraries/LibJS/Runtime/ProxyObject.cpp
index 8216918fd8..803ba3dd74 100644
--- a/Userland/Libraries/LibJS/Runtime/ProxyObject.cpp
+++ b/Userland/Libraries/LibJS/Runtime/ProxyObject.cpp
@@ -798,13 +798,23 @@ MarkedValueList ProxyObject::internal_own_property_keys() const
         return MarkedValueList { heap() };
 
     // 8. Let trapResult be ? CreateListFromArrayLike(trapResultArray, « String, Symbol »).
-    auto trap_result = create_list_from_array_like(global_object, trap_result_array, [](auto value) -> Result<void, ErrorType> {
-        if (!value.is_string() && !value.is_symbol())
-            return ErrorType::ProxyOwnPropertyKeysNotStringOrSymbol;
-        return {};
+    HashTable<StringOrSymbol> unique_keys;
+    auto trap_result = create_list_from_array_like(global_object, trap_result_array, [&](auto value) {
+        auto& vm = global_object.vm();
+        if (!value.is_string() && !value.is_symbol()) {
+            vm.throw_exception<TypeError>(global_object, ErrorType::ProxyOwnPropertyKeysNotStringOrSymbol);
+            return;
+        }
+        auto property_key = value.to_property_key(global_object);
+        VERIFY(!vm.exception());
+        unique_keys.set(property_key, AK::HashSetExistingEntryBehavior::Keep);
     });
 
-    // FIXME: 9. If trapResult contains any duplicate entries, throw a TypeError exception.
+    // 9. If trapResult contains any duplicate entries, throw a TypeError exception.
+    if (unique_keys.size() != trap_result.size()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::ProxyOwnPropertyKeysDuplicates);
+        return MarkedValueList { heap() };
+    }
 
     // 10. Let extensibleTarget be ? IsExtensible(target).
     auto extensible_target = m_target.is_extensible();