Object: Introduce set and setIndexed

These names are what the ES6 spec uses for this operation. We also
introduce a bool to allow throwing unconditionally if a set fails (which
the spec requires the Set operation to do in a number of places). This
requirement was also present in ES5, but we ignored it, and thus far got
away with it.

Long term, put and putIndexed should go away, but I don't feel
comfortable porting everything over blindly, as some operations do
require throwing, namely:

* Various Array & TypedArray methods that alter 'length'
* Various RegExp methods that alter 'lastIndex'

This change also ports the new Object.assign to use the must-throw
version of set(), which coincidentally fixes the one test failure in
non-strict mode.

Change-Id: Ida641a552d805af0fd9de3333eb62cc6adb3713c
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

3 files changed, 40 insertions, 1 deletions

diff --git a/src/qml/jsruntime/qv4object.cpp b/src/qml/jsruntime/qv4object.cpp
index 0ef53d5703..b95bfb85a7 100644
--- a/src/qml/jsruntime/qv4object.cpp
+++ b/src/qml/jsruntime/qv4object.cpp
@@ -790,6 +790,7 @@ bool Object::internalPut(String *name, const Value &value)
     return true;
 
   reject:
+    // ### this should be removed once everything is ported to use Object::set()
     if (engine()->current->strictMode) {
         QString message = QLatin1String("Cannot assign to read-only property \"") +
                 name->toQString() + QLatin1Char('\"');
@@ -861,6 +862,7 @@ bool Object::internalPutIndexed(uint index, const Value &value)
     return true;
 
   reject:
+    // ### this should be removed once everything is ported to use Object::setIndexed()
     if (engine()->current->strictMode)
         engine()->throwTypeError();
     return false;
diff --git a/src/qml/jsruntime/qv4object_p.h b/src/qml/jsruntime/qv4object_p.h
index d321df2451..0d17afbf41 100644
--- a/src/qml/jsruntime/qv4object_p.h
+++ b/src/qml/jsruntime/qv4object_p.h
@@ -336,10 +336,47 @@ public:
     { return vtable()->get(this, name, hasProperty); }
     inline ReturnedValue getIndexed(uint idx, bool *hasProperty = 0) const
     { return vtable()->getIndexed(this, idx, hasProperty); }
+
+    // use the set variants instead, to customize throw behavior
     inline bool put(String *name, const Value &v)
     { return vtable()->put(this, name, v); }
     inline bool putIndexed(uint idx, const Value &v)
     { return vtable()->putIndexed(this, idx, v); }
+
+    enum ThrowOnFailure {
+        DoThrowOnRejection,
+        DoNotThrow
+    };
+
+    // ES6: 7.3.3 Set (O, P, V, Throw)
+    inline bool set(String *name, const Value &v, ThrowOnFailure shouldThrow)
+    {
+        bool ret = vtable()->put(this, name, v);
+        // ES6: 7.3.3, 6: If success is false and Throw is true, throw a TypeError exception.
+        if (!ret && shouldThrow == ThrowOnFailure::DoThrowOnRejection) {
+            ExecutionEngine *e = engine();
+            if (!e->hasException) { // allow a custom set impl to throw itself
+                QString message = QLatin1String("Cannot assign to read-only property \"") +
+                        name->toQString() + QLatin1Char('\"');
+                e->throwTypeError(message);
+            }
+        }
+        return ret;
+    }
+
+    inline bool setIndexed(uint idx, const Value &v, ThrowOnFailure shouldThrow)
+    {
+        bool ret = vtable()->putIndexed(this, idx, v);
+        if (!ret && shouldThrow == ThrowOnFailure::DoThrowOnRejection) {
+            ExecutionEngine *e = engine();
+            if (!e->hasException) { // allow a custom set impl to throw itself
+                e->throwTypeError();
+            }
+        }
+        return ret;
+    }
+
+
     PropertyAttributes query(String *name) const
     { return vtable()->query(this, name); }
     PropertyAttributes queryIndexed(uint index) const
diff --git a/src/qml/jsruntime/qv4objectproto.cpp b/src/qml/jsruntime/qv4objectproto.cpp
index d8063c64de..f650ffc7b1 100644
--- a/src/qml/jsruntime/qv4objectproto.cpp
+++ b/src/qml/jsruntime/qv4objectproto.cpp
@@ -194,7 +194,7 @@ void ObjectPrototype::method_assign(const BuiltinFunction *, Scope &scope, CallD
                 continue;
 
             propValue = from->get(nextKey);
-            to->put(nextKey, propValue);
+            to->set(nextKey, propValue, Object::DoThrowOnRejection);
             CHECK_EXCEPTION();
         }
     }