From cd0031be470328b8d33c38894de590addfce851a Mon Sep 17 00:00:00 2001
From: Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
Date: Mon, 12 Oct 2015 10:02:03 +0200
Subject: [PATCH] router: fix segfault when placing a via with failed shove of
 head trace

---
 pcbnew/router/pns_line_placer.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/pcbnew/router/pns_line_placer.cpp b/pcbnew/router/pns_line_placer.cpp
index aa864e149d..bdc29706f5 100644
--- a/pcbnew/router/pns_line_placer.cpp
+++ b/pcbnew/router/pns_line_placer.cpp
@@ -454,6 +454,12 @@ bool PNS_LINE_PLACER::rhShoveOnly( const VECTOR2I& aP, PNS_LINE& aNewHead )
     l.Line().Append( l2.CLine() );
     l.Line().Simplify();
 
+    if( l.PointCount() == 0 || l2.PointCount() == 0 )
+    {
+        aNewHead = m_head;
+        return false;
+    }
+
     if( m_placingVia && viaOk )
     {
         PNS_VIA v1( makeVia( l.CPoint( -1 ) ) );
@@ -1037,6 +1043,8 @@ bool PNS_LINE_PLACER::buildInitialLine( const VECTOR2I& aP, PNS_LINE& aHead )
 {
     SHAPE_LINE_CHAIN l;
 
+    printf("H-net %d\n", aHead.Net());
+
     if( m_p_start == aP )
     {
         l.Clear();