Measure distance from pad center, not pad hull.

Otherwise we think the wrong end of really short track segments is
connected to the pad, leaving the other end dangling.

Fixes https://gitlab.com/kicad/code/kicad/issues/8909

pcbnew/connectivity/connectivity_data.cpp

@@ -36,6 +36,7 @@
 #include <connectivity/from_to_cache.h>
 
 #include <ratsnest/ratsnest_data.h>
+#include <trigo.h>
 
 CONNECTIVITY_DATA::CONNECTIVITY_DATA()
 {
@@ -586,6 +587,25 @@ void CONNECTIVITY_DATA::GetUnconnectedEdges( std::vector<CN_EDGE>& aEdges) const
 }
 
 
+static int getMinDist( BOARD_CONNECTED_ITEM* aItem, const wxPoint& aPoint )
+{
+    switch( aItem->Type() )
+    {
+    case PCB_TRACE_T:
+    case PCB_ARC_T:
+    {
+        PCB_TRACK* track = static_cast<PCB_TRACK*>( aItem );
+
+        return std::min( GetLineLength( track->GetStart(), aPoint ),
+                         GetLineLength( track->GetEnd(), aPoint ) );
+    }
+
+    default:
+        return GetLineLength( aItem->GetPosition(), aPoint );
+    }
+}
+
+
 bool CONNECTIVITY_DATA::TestTrackEndpointDangling( PCB_TRACK* aTrack, wxPoint* aPos )
 {
     std::list<CN_ITEM*> items = GetConnectivityAlgo()->ItemEntry( aTrack ).GetItems();
@@ -623,14 +643,12 @@ bool CONNECTIVITY_DATA::TestTrackEndpointDangling( PCB_TRACK* aTrack, wxPoint* a
 
             std::shared_ptr<SHAPE> shape = item->GetEffectiveShape( layer );
 
-            int  startDist;
-            int  endDist;
-            bool hitStart = shape->Collide( aTrack->GetStart(), accuracy, &startDist );
-            bool hitEnd = shape->Collide( aTrack->GetEnd(), accuracy, &endDist );
+            bool hitStart = shape->Collide( aTrack->GetStart(), accuracy );
+            bool hitEnd = shape->Collide( aTrack->GetEnd(), accuracy );
 
             if( hitStart && hitEnd )
             {
-                if( startDist <= endDist )
+                if( getMinDist( item, aTrack->GetStart() ) < getMinDist( item, aTrack->GetEnd() ) )
                     start_count++;
                 else
                     end_count++;

pcbnew/connectivity/connectivity_items.cpp

@@ -147,7 +147,6 @@ const VECTOR2I CN_ITEM::GetAnchor( int n ) const
 
     default:
         assert( false );
-        break;
     }
 
     return pt0;

qa/data/issue6879.kicad_pro

@@ -88,12 +88,12 @@
         "silk_overlap": "error",
         "skew_out_of_range": "error",
         "too_many_vias": "error",
-        "track_dangling": "ignore",
+        "track_dangling": "warning",
         "track_width": "error",
         "tracks_crossing": "error",
         "unconnected_items": "error",
         "unresolved_variable": "error",
-        "via_dangling": "ignore",
+        "via_dangling": "warning",
         "zone_has_empty_net": "error",
         "zones_intersect": "error"
       },