Avoid crash from storage of potentially removed map layer storage in canvas

nyalldawson · nyalldawson · commit 56b6ebd91ce5 · 2018-08-17T12:01:54.000+10:00
diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
@@ -285,6 +285,9 @@ QgsMapLayer *QgsMapCanvas::layer( int index )
 
 void QgsMapCanvas::setCurrentLayer( QgsMapLayer *layer )
 {
+  if ( mCurrentLayer == layer )
+    return;
+
   mCurrentLayer = layer;
   emit currentLayerChanged( layer );
 }
diff --git a/src/gui/qgsmapcanvas.h b/src/gui/qgsmapcanvas.h
@@ -928,7 +928,7 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     bool mRenderFlag = true;
 
     //! current layer in legend
-    QgsMapLayer *mCurrentLayer = nullptr;
+    QPointer< QgsMapLayer > mCurrentLayer;
 
     //! graphics scene manages canvas items
     QGraphicsScene *mScene = nullptr;

Original file line number	Diff line number	Diff line change
`@@ -285,6 +285,9 @@ QgsMapLayer *QgsMapCanvas::layer( int index )`
`285`	`285`
`286`	`286`	`void QgsMapCanvas::setCurrentLayer( QgsMapLayer *layer )`
`287`	`287`	`{`
	`288`	`+ if ( mCurrentLayer == layer )`
	`289`	`+ return;`
	`290`	`+`
`288`	`291`	`mCurrentLayer = layer;`
`289`	`292`	`emit currentLayerChanged( layer );`
`290`	`293`	`}`