QMetaProperty::write should reset the property if an empty QVariant is given

[ChangeLog][QtCore][QMetaProperty] write() now resets the property if an
empty QVariant is given, or set a default constructed object if the
property is not resettable

Change-Id: I9f9b57114e740f03ec4db6f223c1e8280a3d5209
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/src/corelib/kernel/qmetaobject.cpp b/src/corelib/kernel/qmetaobject.cpp
index 6abec27684..820af298c0 100644
--- a/src/corelib/kernel/qmetaobject.cpp
+++ b/src/corelib/kernel/qmetaobject.cpp
@@ -3028,6 +3028,11 @@ QVariant QMetaProperty::read(const QObject *object) const
     Writes \a value as the property's value to the given \a object. Returns
     true if the write succeeded; otherwise returns \c false.
 
+    If \a value is not of the same type type as the property, a conversion
+    is attempted. An empty QVariant() is equivalent to a call to reset()
+    if this property is resetable, or setting a default-constructed object
+    otherwise.
+
     \sa read(), reset(), isWritable()
 */
 bool QMetaProperty::write(QObject *object, const QVariant &value) const
@@ -3068,8 +3073,15 @@ bool QMetaProperty::write(QObject *object, const QVariant &value) const
             if (t == QMetaType::UnknownType)
                 return false;
         }
-        if (t != QMetaType::QVariant && int(t) != value.userType() && !v.convert(t))
-            return false;
+        if (t != QMetaType::QVariant && int(t) != value.userType()) {
+            if (!value.isValid()) {
+                if (isResettable())
+                    return reset(object);
+                v = QVariant(t, 0);
+            } else if (!v.convert(t)) {
+                return false;
+            }
+        }
     }
 
     // the status variable is changed by qt_metacall to indicate what it did