Coverity: Dereference after null check

src/Mod/TechDraw/Gui/QGIViewBalloon.cpp

@@ -366,7 +366,7 @@ void QGIViewBalloon::setViewPartFeature(TechDraw::DrawViewBalloon *balloon)
     DrawView* balloonParent = nullptr;
     double scale = 1.0;
     App::DocumentObject* docObj = balloon->SourceView.getValue();
-    if (docObj == nullptr) {
+    if (docObj) {
         balloonParent = dynamic_cast<DrawView*>(docObj);
         if (balloonParent)
             scale = balloonParent->getScale();

src/Mod/TechDraw/Gui/TaskCenterLine.cpp

@@ -97,8 +97,10 @@ TaskCenterLine::TaskCenterLine(TechDraw::DrawViewPart* partFeat,
     if (m_cl == nullptr) {         //checked by CommandAnnotate.  Should never happen.
         Base::Console().Message("TCL::TCL() - no centerline found\n");
     }
-    m_type = m_cl->m_type;
-    m_mode = m_cl->m_mode;
+    else {
+        m_type = m_cl->m_type;
+        m_mode = m_cl->m_mode;
+    }
 
     setUiEdit();
 }

src/Mod/TechDraw/Gui/TaskDetail.cpp

@@ -95,6 +95,7 @@ TaskDetail::TaskDetail(TechDraw::DrawViewPart* baseFeat):
     m_basePage = m_baseFeat->findParentPage();
     if (m_basePage == nullptr) {
         Base::Console().Error("TaskDetail - bad parameters - base page.  Can not proceed.\n");
+        return;
     }
 
     m_baseName = m_baseFeat->getNameInDocument();

src/Mod/TechDraw/Gui/TaskLeaderLine.cpp

@@ -421,7 +421,9 @@ void TaskLeaderLine::createLeaderFeature(std::vector<Base::Vector3d> converted)
     if (m_basePage != nullptr) {
         m_basePage->touch();
     }
-    m_lineFeat->requestPaint();
+    if (m_lineFeat != nullptr) {
+        m_lineFeat->requestPaint();
+    }
 }
 
 void TaskLeaderLine::updateLeaderFeature(void)