Measure: Fix TaskMeasure

Made several fixes to TaskMeasure:
* Move to correct namespace
* Handle possible exception in update() method
* Add null pointer checks for buttonBox
* Cannot use 'Measure::MeasurePython' as template argument in addObject<>
  because the macro PROPERTY_HEADER_WITH_OVERRIDE determines the invalid
  string 'App::FeaturePythonT<FeatureT>' so that an exception is raised

Note: The changes might fix issue 20304

src/App/Document.cpp

@@ -3065,7 +3065,7 @@ DocumentObject* Document::addObject(const char* sType,
         Base::Type::getTypeIfDerivedFrom(sType, DocumentObject::getClassTypeId(), true);
     if (type.isBad()) {
         std::stringstream str;
-        str << "'" << sType << "' is not a document object type";
+        str << "Document::addObject: '" << sType << "' is not a document object type";
         throw Base::TypeError(str.str());
     }
 

src/Mod/Measure/Gui/Command.cpp

@@ -62,7 +62,7 @@ void StdCmdMeasure::activated(int iMsg)
 {
     Q_UNUSED(iMsg);
 
-    Gui::TaskMeasure* task = new Gui::TaskMeasure();
+    MeasureGui::TaskMeasure* task = new MeasureGui::TaskMeasure();
     task->setDocumentName(this->getDocument()->getName());
     Gui::Control().showDialog(task);
 }

src/Mod/Measure/Gui/TaskMeasure.cpp

@@ -48,7 +48,7 @@
 #include <QMenu>
 #include <QToolTip>
 
-using namespace Gui;
+using namespace MeasureGui;
 
 namespace
 {
@@ -225,7 +225,9 @@ Measure::MeasureBase* TaskMeasure::createObject(const App::MeasureType* measureT
         auto pyMeasureClass = measureType->pythonClass;
 
         // Create a MeasurePython instance
-        // Measure::MeasurePython is an alias so we need to use the string based addObject for now.
+        // Note: writing addObject<Measure::MeasurePython>() is not yet supported because
+        // getClassName() will determine the string 'App::FeaturePythonT<FeatureT>' instead
+        // of 'Measure::MeasurePython'
         auto featurePython = doc->addObject("Measure::MeasurePython", measureType->label.c_str());
         _mMeasureObject = dynamic_cast<Measure::MeasureBase*>(featurePython);
 
@@ -245,8 +247,17 @@ Measure::MeasureBase* TaskMeasure::createObject(const App::MeasureType* measureT
     return _mMeasureObject;
 }
 
-
 void TaskMeasure::update()
+{
+    try {
+        tryUpdate();
+    }
+    catch (const Base::Exception& e) {
+        e.reportException();
+    }
+}
+
+void TaskMeasure::tryUpdate()
 {
     App::Document* doc = App::GetApplication().getActiveDocument();
 
@@ -274,7 +285,7 @@ void TaskMeasure::update()
     std::string mode = explicitMode ? modeSwitch->currentText().toStdString() : "";
 
     App::MeasureSelection selection;
-    for (auto s : Gui::Selection().getSelection(doc->getName(), ResolveMode::NoResolve)) {
+    for (auto s : Gui::Selection().getSelection(doc->getName(), Gui::ResolveMode::NoResolve)) {
         App::SubObjectT sub(s.pObject, s.SubName);
 
         App::MeasureSelectionItem item = {sub, Base::Vector3d(s.x, s.y, s.z)};
@@ -358,7 +369,7 @@ void TaskMeasure::initViewObject()
 
 void TaskMeasure::close()
 {
-    Control().closeDialog();
+    Gui::Control().closeDialog();
 }
 
 
@@ -460,9 +471,10 @@ void TaskMeasure::clearSelection()
 void TaskMeasure::onSelectionChanged(const Gui::SelectionChanges& msg)
 {
     // Skip non-relevant events
-    if (msg.Type != SelectionChanges::AddSelection && msg.Type != SelectionChanges::RmvSelection
-        && msg.Type != SelectionChanges::SetSelection
-        && msg.Type != SelectionChanges::ClrSelection) {
+    if (msg.Type != Gui::SelectionChanges::AddSelection
+        && msg.Type != Gui::SelectionChanges::RmvSelection
+        && msg.Type != Gui::SelectionChanges::SetSelection
+        && msg.Type != Gui::SelectionChanges::ClrSelection) {
 
         return;
     }
@@ -476,9 +488,9 @@ void TaskMeasure::onSelectionChanged(const Gui::SelectionChanges& msg)
     const bool shift = (modifier & Qt::ShiftModifier) > 0;
     // shift inverts the current state temporarily
     const auto autosave = (mAutoSave && !shift) || (!mAutoSave && shift);
-    if ((!ctrl && Selection().getSelectionStyle() == SelectionStyle::NormalSelection)
-        || (ctrl && Selection().getSelectionStyle() == SelectionStyle::GreedySelection)) {
-        if (autosave && this->buttonBox->button(QDialogButtonBox::Apply)->isEnabled()) {
+    if ((!ctrl && Gui::Selection().getSelectionStyle() == SelectionStyle::NormalSelection)
+        || (ctrl && Gui::Selection().getSelectionStyle() == SelectionStyle::GreedySelection)) {
+        if (autosave && buttonBox && buttonBox->button(QDialogButtonBox::Apply)->isEnabled()) {
             apply(false);
         }
     }
@@ -506,7 +518,9 @@ bool TaskMeasure::eventFilter(QObject* obj, QEvent* event)
         if (keyEvent->key() == Qt::Key_Return || keyEvent->key() == Qt::Key_Enter) {
             // Save object. Indirectly dependent on whether the apply button is enabled
             // enabled if valid measurement object.
-            this->buttonBox->button(QDialogButtonBox::Apply)->click();
+            if (buttonBox) {
+                buttonBox->button(QDialogButtonBox::Apply)->click();
+            }
             return true;
         }
     }

src/Mod/Measure/Gui/TaskMeasure.h

@@ -41,10 +41,10 @@
 #include <Gui/TaskView/TaskView.h>
 #include <Gui/Selection/Selection.h>
 
-namespace Gui
+namespace MeasureGui
 {
 
-class TaskMeasure: public TaskView::TaskDialog, public Gui::SelectionObserver
+class TaskMeasure: public Gui::TaskView::TaskDialog, public Gui::SelectionObserver
 {
 
 public:
@@ -70,6 +70,7 @@ public:
     bool eventFilter(QObject* obj, QEvent* event) override;
 
 private:
+    void tryUpdate();
     void onSelectionChanged(const Gui::SelectionChanges& msg) override;
 
     Measure::MeasureBase* _mMeasureObject = nullptr;
@@ -103,6 +104,6 @@ private:
     bool mAutoSave = false;
 };
 
-}  // namespace Gui
+}  // namespace MeasureGui
 
 #endif  // MEASURE_TASKMEASURE_H