From 812c56bdc74417545ff0a0567603c182ed3c593b Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Tue, 25 Jul 2023 11:05:56 -0700
Subject: [PATCH] Clarify NeighboringSegmentFilter

This doesn't affect behavior but makes the code more readable
---
 pcbnew/router/router_tool.cpp | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/pcbnew/router/router_tool.cpp b/pcbnew/router/router_tool.cpp
index aa5dbd7553..98c0a19733 100644
--- a/pcbnew/router/router_tool.cpp
+++ b/pcbnew/router/router_tool.cpp
@@ -2036,7 +2036,20 @@ void ROUTER_TOOL::NeighboringSegmentFilter( const VECTOR2I& aPt, GENERAL_COLLECT
     int traces = aCollector.CountType( PCB_TRACE_T );
     int arcs = aCollector.CountType( PCB_ARC_T );
 
-    if( arcs > 0 || vias > 1 || traces > 2 || vias + traces < 1 )
+    // We eliminate arcs because they are not supported in the inline drag code.
+    if( arcs > 0 )
+        return;
+
+    // We need to have at least 1 via or track
+    if( vias + traces == 0 )
+        return;
+
+    // We cannot drag more than one via at a time
+    if( vias > 1 )
+        return;
+
+    // We cannot drag more than two track segments at a time
+    if( traces > 2 )
         return;
 
     // Fetch first PCB_TRACK (via or trace) as our reference
@@ -2045,6 +2058,10 @@ void ROUTER_TOOL::NeighboringSegmentFilter( const VECTOR2I& aPt, GENERAL_COLLECT
     for( int i = 0; !reference && i < aCollector.GetCount(); i++ )
         reference = dynamic_cast<PCB_TRACK*>( aCollector[i] );
 
+    // This should never happen, but just in case...
+    if( !reference )
+        return;
+
     int refNet = reference->GetNetCode();
 
     VECTOR2I       refPoint( aPt.x, aPt.y );