#12558 Summary Plot: Fix crash when deleting sub plots.

The std::unique_ptr<RiuPlotWidget> would delete the widget when
RimSummaryPlot object was recreated. This would lead to a
double-delete since the RiuPlotWidget was already deleted by Qt
through the parent-child relationship.

Fixed by using QPointer, and leaving the cleanup to Qt.

Fixes #12558.

ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.cpp

@@ -1898,17 +1898,12 @@ void RimSummaryPlot::deletePlotCurvesAndPlotWidget()
     if ( isDeletable() )
     {
         detachAllPlotItems();
-
-        if ( plotWidget() )
-        {
-            plotWidget()->setParent( nullptr );
-        }
-
         deleteAllPlotCurves();
 
         if ( m_summaryPlot )
         {
-            m_summaryPlot.reset();
+            // The RiuPlotWidget is owned by Qt, and will be deleted when its parent is destructed.
+            m_summaryPlot.clear();
         }
     }
 }
@@ -2604,9 +2599,10 @@ void RimSummaryPlot::defineUiOrdering( QString uiConfigName, caf::PdmUiOrdering&
 //--------------------------------------------------------------------------------------------------
 RiuPlotWidget* RimSummaryPlot::doCreatePlotViewWidget( QWidget* mainWindowParent )
 {
+    CAF_ASSERT( mainWindowParent );
     if ( !plotWidget() )
     {
-        m_summaryPlot = std::make_unique<RiuSummaryQwtPlot>( this, mainWindowParent );
+        m_summaryPlot = new RiuSummaryQwtPlot( this, mainWindowParent );
 
         QObject::connect( plotWidget(), SIGNAL( curveOrderNeedsUpdate() ), this, SLOT( onUpdateCurveOrder() ) );
 
@@ -2640,8 +2636,6 @@ RiuPlotWidget* RimSummaryPlot::doCreatePlotViewWidget( QWidget* mainWindowParent
         updatePlotTitle();
     }
 
-    plotWidget()->setParent( mainWindowParent );
-
     return plotWidget();
 }
 

ApplicationLibCode/ProjectDataModel/Summary/RimSummaryPlot.h

@@ -338,7 +338,7 @@ private:
 
     caf::PdmChildArrayField<RimPlotAxisPropertiesInterface*> m_axisPropertiesArray;
 
-    std::unique_ptr<RiuSummaryPlot>   m_summaryPlot;
+    QPointer<RiuSummaryPlot>          m_summaryPlot;
     std::unique_ptr<QwtPlotTextLabel> m_plotInfoLabel;
 
     std::unique_ptr<RimSummaryPlotNameHelper>         m_nameHelperAllCurves;