FunctionObject: Mark name/length property configurable

In ES5, these were not configurable, but ES6 changed the behavior.

For length, refer to:
    9.2.4 (FunctionInitialize)
    17 (ECMAScript Standard Built-in Objects):
        Unless otherwise specified, the length property of a built-in Function
        object has the attributes { [[Writable]]: false, [[Enumerable]]: false,
        [[Configurable]]: true }.
    19.2.2.1 Function.length
    19.2.3.2 (Function.prototype.bind)
    19.2.4.1 (Function instances, length)

For name, refer to:
    9.2.11 (SetFunctionName)

This does regress test262 for ES5 for me a little, but improves our es6 test
coverage a bit (~682 more tests pass, +1.5%).

Change-Id: Icda7c9068dc3e6e4e4aebbb0d359868a30343013
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 17 insertions, 4 deletions

diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index 2f664c6398..59195fc11e 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -162,7 +162,7 @@ void Object::defineDefaultProperty(const QString &name, ReturnedValue (*code)(Ca
     ScopedString s(scope, e->newIdentifier(name));
     ExecutionContext *global = e->rootContext();
     ScopedFunctionObject function(scope, BuiltinFunction::create(global, s, code));
-    function->defineReadonlyProperty(e->id_length(), Primitive::fromInt32(argumentCount));
+    function->defineReadonlyConfigurableProperty(e->id_length(), Primitive::fromInt32(argumentCount));
     defineDefaultProperty(s, function);
 }
 
@@ -173,7 +173,7 @@ void Object::defineDefaultProperty(const QString &name, void (*code)(const Built
     ScopedString s(scope, e->newIdentifier(name));
     ExecutionContext *global = e->rootContext();
     ScopedFunctionObject function(scope, BuiltinFunction::create(global, s, code));
-    function->defineReadonlyProperty(e->id_length(), Primitive::fromInt32(argumentCount));
+    function->defineReadonlyConfigurableProperty(e->id_length(), Primitive::fromInt32(argumentCount));
     defineDefaultProperty(s, function);
 }
 
@@ -183,7 +183,7 @@ void Object::defineDefaultProperty(String *name, ReturnedValue (*code)(CallConte
     Scope scope(e);
     ExecutionContext *global = e->rootContext();
     ScopedFunctionObject function(scope, BuiltinFunction::create(global, name, code));
-    function->defineReadonlyProperty(e->id_length(), Primitive::fromInt32(argumentCount));
+    function->defineReadonlyConfigurableProperty(e->id_length(), Primitive::fromInt32(argumentCount));
     defineDefaultProperty(name, function);
 }
 
@@ -193,7 +193,7 @@ void Object::defineDefaultProperty(String *name, void (*code)(const BuiltinFunct
     Scope scope(e);
     ExecutionContext *global = e->rootContext();
     ScopedFunctionObject function(scope, BuiltinFunction::create(global, name, code));
-    function->defineReadonlyProperty(e->id_length(), Primitive::fromInt32(argumentCount));
+    function->defineReadonlyConfigurableProperty(e->id_length(), Primitive::fromInt32(argumentCount));
     defineDefaultProperty(name, function);
 }
 
@@ -250,6 +250,19 @@ void Object::defineReadonlyProperty(String *name, const Value &value)
     insertMember(name, value, Attr_ReadOnly);
 }
 
+void Object::defineReadonlyConfigurableProperty(const QString &name, const Value &value)
+{
+    QV4::ExecutionEngine *e = engine();
+    Scope scope(e);
+    ScopedString s(scope, e->newIdentifier(name));
+    defineReadonlyConfigurableProperty(s, value);
+}
+
+void Object::defineReadonlyConfigurableProperty(String *name, const Value &value)
+{
+    insertMember(name, value, Attr_ReadOnly_ButConfigurable);
+}
+
 void Object::markObjects(Heap::Base *that, ExecutionEngine *e)
 {
     Heap::Object *o = static_cast<Heap::Object *>(that);