Merge pull request #24970 from maxwxyz/cp_18075

src/App/Property.cpp

@@ -247,10 +247,28 @@ void Property::destroy(Property* p)
     }
 }
 
+bool Property::enableNotify(bool enable)
+{
+    bool isNotify = isNotifyEnabled();
+
+    if (enable) {
+        StatusBits.reset(DisableNotify);
+    }
+    else {
+        StatusBits.set(DisableNotify);
+    }
+    return isNotify;
+}
+
+bool Property::isNotifyEnabled() const
+{
+    return !StatusBits.test(DisableNotify);
+}
+
 void Property::touch()
 {
     PropertyCleaner guard(this);
-    if (father) {
+    if (father && isNotifyEnabled()) {
         father->onEarlyChange(this);
         father->onChanged(this);
     }
@@ -266,7 +284,9 @@ void Property::hasSetValue()
 {
     PropertyCleaner guard(this);
     if (father) {
-        father->onChanged(this);
+        if (isNotifyEnabled()) {
+            father->onChanged(this);
+        }
         if (!testStatus(Busy)) {
             Base::BitsetLocker<decltype(StatusBits)> guard(StatusBits, Busy);
             signalChanged(*this);

src/App/Property.h

@@ -108,6 +108,8 @@ public:
         CopyOnChange = 16,
         /// Whether the property editor should create a button for user defined editing.
         UserEdit = 17,
+        /// Do not propagate changes of the property to its container
+        DisableNotify = 18,
 
         // The following bits are corresponding to PropertyType set when the
         // property added. These types are meant to be static, and cannot be
@@ -354,11 +356,16 @@ public:
      */
     virtual void onContainerRestored() {}
 
-    /** @name Property status handling
-     * @{
+    /** Property status handling
      */
-
-    /// Set the property touched.
+    //@{
+    /// This method sets whether notification will be propagated on changing
+    /// the value of the property. The old value of the setting is returned.
+    bool enableNotify(bool on);
+    /// This method returns whether notification of changes to the property value
+    /// are propagated to the container.
+    bool isNotifyEnabled() const;
+    /// Set the property touched
     void touch();
 
     /**

src/Mod/PartDesign/Gui/ViewProviderBody.cpp

@@ -263,10 +263,23 @@ void ViewProviderBody::onChanged(const App::Property* prop) {
         // #0002559: Body becomes visible upon changing DisplayModeBody
         Visibility.touch();
     }
-    else
+    else {
         unifyVisualProperty(prop);
+    }
+
+    // When changing transparency then adjust the ShapeAppearance inside onChanged()
+    // of the base class but don't notify its container again. This breaks the chain of
+    // notification and avoids the call of onChanged() with the ShapeAppearance as argument
+    // This fixes issue https://github.com/FreeCAD/FreeCAD/issues/18075
+    if (prop == &Transparency) {
+        ShapeAppearance.enableNotify(false);
+    }
 
     PartGui::ViewProviderPartExt::onChanged(prop);
+
+    if (prop == &Transparency) {
+        ShapeAppearance.enableNotify(true);
+    }
 }