Designer: Remember default of main container's object name.

as a default property value. Users can then safely reset it
to its original value. The default-generated name previously
led to the uic-generated file names to be different,
causing build errors in IDE's.

Task-number: QTBUG-18256

2 files changed, 15 insertions, 3 deletions

diff --git a/tools/designer/src/components/formeditor/qdesigner_resource.cpp b/tools/designer/src/components/formeditor/qdesigner_resource.cpp
index 714a556..005459b 100644
--- a/tools/designer/src/components/formeditor/qdesigner_resource.cpp
+++ b/tools/designer/src/components/formeditor/qdesigner_resource.cpp
@@ -741,7 +741,10 @@ QWidget *QDesignerResource::load(QIODevice *dev, QWidget *parentWidget)
     case LoadPreCheckOk:
         break;
     }
-    return QEditorFormBuilder::load(dev, parentWidget);
+    QWidget *w = QEditorFormBuilder::load(dev, parentWidget);
+    if (w) // Store the class name as 'reset' value for the main container's object name.
+        w->setProperty("_q_classname", w->objectName());
+    return w;
 }
 
 bool QDesignerResource::saveRelative() const
diff --git a/tools/designer/src/lib/shared/qdesigner_propertysheet.cpp b/tools/designer/src/lib/shared/qdesigner_propertysheet.cpp
index babe20e..27527da 100644
--- a/tools/designer/src/lib/shared/qdesigner_propertysheet.cpp
+++ b/tools/designer/src/lib/shared/qdesigner_propertysheet.cpp
@@ -1195,8 +1195,17 @@ bool QDesignerPropertySheet::reset(int index)
 {
     if (d->invalidIndex(Q_FUNC_INFO, index))
         return false;
-    if (d->isStringProperty(index))
-        setProperty(index, QVariant::fromValue(qdesigner_internal::PropertySheetStringValue()));
+    if (d->isStringProperty(index)) {
+        qdesigner_internal::PropertySheetStringValue value;
+        // Main container: Reset to stored class name as not to change the file names generated by uic.
+        if (propertyName(index) == QLatin1String("objectName")) {
+            const QVariant classNameDefaultV = d->m_object->property("_q_classname");
+            if (classNameDefaultV.isValid())
+                value.setValue(classNameDefaultV.toString());
+        }
+        setProperty(index, QVariant::fromValue(value));
+        return true;
+    }
     if (d->isKeySequenceProperty(index))
         setProperty(index, QVariant::fromValue(qdesigner_internal::PropertySheetKeySequenceValue()));
     if (d->isResourceProperty(index)) {