From ac4978cf8ad97f31e5b15f6c26efc7451a64a18c Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Wed, 23 Sep 2020 18:42:35 +0100
Subject: [PATCH] Some defensive code which may prevent a freed-memory-access.

Fixes https://gitlab.com/kicad/code/kicad/issues/5747
---
 common/rc_item.cpp | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/common/rc_item.cpp b/common/rc_item.cpp
index 6cceac68af..9b43141a00 100644
--- a/common/rc_item.cpp
+++ b/common/rc_item.cpp
@@ -432,18 +432,32 @@ void RC_TREE_MODEL::DeleteItems( bool aCurrentOnly, bool aIncludeExclusions, boo
         return;
     }
 
+    int  lastGood = -1;
+    bool found = false;
+
+    if( m_view )
+        m_view->UnselectAll();
+
     for( int i = m_rcItemsProvider->GetCount() - 1; i >= 0; --i )
     {
-        std::shared_ptr<RC_ITEM>     rcItem = m_rcItemsProvider->GetItem( i );
-        MARKER_BASE* marker = rcItem->GetParent();
-        bool         excluded = marker ? marker->IsExcluded() : false;
+        std::shared_ptr<RC_ITEM> rcItem = m_rcItemsProvider->GetItem( i );
+        MARKER_BASE*             marker = rcItem->GetParent();
+        bool                     excluded = marker ? marker->IsExcluded() : false;
 
         if( aCurrentOnly && rcItem != current_item )
+        {
+            if( found && lastGood >= 0 )
+                break;
+
+            lastGood = i;
             continue;
+        }
 
         if( excluded && !aIncludeExclusions )
             continue;
 
+        found = true;
+
         wxDataViewItem      markerItem = ToItem( m_tree[i] );
         wxDataViewItemArray childItems;
         wxDataViewItem      parentItem = ToItem( m_tree[i]->m_Parent );
@@ -466,6 +480,9 @@ void RC_TREE_MODEL::DeleteItems( bool aCurrentOnly, bool aIncludeExclusions, boo
         m_rcItemsProvider->DeleteItem( i, aDeep && aCurrentOnly );
     }
 
+    if( m_view && aCurrentOnly && lastGood >= 0 )
+        m_view->Select( ToItem( m_tree[ lastGood ] ) );
+
     if( !aCurrentOnly )
     {
         m_rcItemsProvider->DeleteAllItems( aIncludeExclusions, aDeep );