Fix a crash when trying to removeMapLayer a null pointer

Author: Hugo Mercier

src/core/qgsmaplayerregistry.cpp

@@ -131,14 +131,18 @@ void QgsMapLayerRegistry::removeMapLayers( const QList<QgsMapLayer*>& layers )
 
   Q_FOREACH ( QgsMapLayer* layer, layers )
   {
-    layerIds << layer->id();
+    if ( layer )
+      layerIds << layer->id();
   }
 
   emit layersWillBeRemoved( layerIds );
   emit layersWillBeRemoved( layers );
 
   Q_FOREACH ( QgsMapLayer* lyr, layers )
   {
+    if ( !lyr )
+      continue;
+
     QString myId( lyr->id() );
     if ( mOwnedLayers.contains( lyr ) )
     {

src/core/qgsmaplayerregistry.h

@@ -129,7 +129,7 @@ class CORE_EXPORT QgsMapLayerRegistry : public QObject
      * The layers being removed are deleted as well as the registry
      * table entries.
      *
-     * @param layers  The layers to remove
+     * @param layers  The layers to remove. Null pointers are ignored
      *
      * @note As a side-effect QgsProject is made dirty.
      */
@@ -159,7 +159,7 @@ class CORE_EXPORT QgsMapLayerRegistry : public QObject
      * The layer being removed is deleted as well as the registry
      * table entry.
      *
-     * @param layer   The layer to remove
+     * @param layer   The layer to remove. Nothing happens if the pointer is null
      *
      * @note As a side-effect QgsProject is made dirty.
      */