From 3c1970434993eb8d09b0190a218a17c79da75e14 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Mon, 2 Mar 2020 07:26:46 -0800
Subject: [PATCH] PNS: Don't add null items to drag

Not all footprint pad items are connected to elements in the PNS, so if
we don't find the parent element, we avoid later crashes/assertions by
skipping their addition

Fixes #3972 | https://gitlab.com/kicad/code/kicad/issues/3972
---
 pcbnew/router/router_tool.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/pcbnew/router/router_tool.cpp b/pcbnew/router/router_tool.cpp
index f9ec861f9a..5f0217b649 100644
--- a/pcbnew/router/router_tool.cpp
+++ b/pcbnew/router/router_tool.cpp
@@ -1205,13 +1205,17 @@ int ROUTER_TOOL::InlineDrag( const TOOL_EVENT& aEvent )
         for ( const auto p : mod->Pads() )
         {
             auto solid = m_router->GetWorld()->FindItemByParent( p );
-            itemsToDrag.Add( solid );
+
+            if( solid )
+                itemsToDrag.Add( solid );
         }
     }
     else
     {
         startItem = m_router->GetWorld()->FindItemByParent( static_cast<const BOARD_CONNECTED_ITEM*>( item ) );
-        itemsToDrag.Add( startItem );
+
+        if( startItem)
+            itemsToDrag.Add( startItem );
     }
 
     if( startItem && startItem->IsLocked() )