Fix broken select connection behavior.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/19790

(cherry picked from commit 93cac7d0a5c6c94896b5f10c960ac9db4f58a436)

eeschema/sch_item.h

@@ -451,6 +451,20 @@ public:
         return false;
     }
 
+    /**
+     * Test if \a aPt is an end point of this schematic object.
+     *
+     * @note The end point test doe **not** imply electrical connectivity.  See IsConnectable().
+     *       In other words all connection points are end points but not all end points are
+     *       connection points such as graphical lines and arcs.  Override this method for all
+     *       objects that have end points.
+     *
+     * @param aPt is the coordinate to test for an end point.
+     * @retval true if \a aPt is an end point.
+     * @retval false if \a aPt is not an end point.
+     */
+    virtual bool IsEndPoint( const VECTOR2I& aPt ) const { return false; }
+
     virtual bool IsDangling() const { return false; }
 
     virtual bool CanConnect( const SCH_ITEM* aItem ) const { return m_layer == aItem->GetLayer(); }

eeschema/sch_line.h

@@ -87,7 +87,7 @@ public:
         return false;
     }
 
-    bool IsEndPoint( const VECTOR2I& aPoint ) const
+    bool IsEndPoint( const VECTOR2I& aPoint ) const override
     {
         return aPoint == m_start || aPoint == m_end;
     }

eeschema/sch_screen.cpp

@@ -439,33 +439,21 @@ std::set<SCH_ITEM*> SCH_SCREEN::MarkConnections( SCH_LINE* aSegment, bool aSecon
             if( item->GetLayer() != line->GetLayer() )
                 continue;
 
+            // SCH_RTREE::Overlapping() included crossing lines.
+            if( !item->IsEndPoint( line->GetStartPoint() ) && !item->IsEndPoint( line->GetEndPoint() ) )
+                continue;
+
+            to_search.push( line );
+            retval.insert( line );
+
             for( VECTOR2I pt : { line->GetStartPoint(), line->GetEndPoint() } )
             {
                 if( item->IsConnected( pt ) )
                 {
                     SCH_ITEM* junction = GetItem( pt, 0, SCH_JUNCTION_T );
-                    SCH_ITEM*      pin = GetItem( pt, 0, SCH_PIN_T );
 
-                    if( item->IsSelected() && aSecondPass )
+                    if( aSecondPass && junction )
-                    {
+                        retval.insert( junction );
-                        if( junction )
-                            retval.insert( junction );
-
-                        retval.insert( line );
-                        to_search.push( line );
-                    }
-                    else if( !junction && !pin )
-                    {
-                        retval.insert( line );
-                        to_search.push( line );
-                    }
-
-                    break;
-                }
-                else if( line->GetLayer() == LAYER_NOTES && item->GetLayer() == LAYER_NOTES )
-                {
-                    retval.insert( line );
-                    to_search.push( line );
                 }
             }
         }

eeschema/sch_screen.h

@@ -299,9 +299,13 @@ public:
 
     /**
      * Return all wires and junctions connected to \a aSegment which are not connected any
-     * symbol pin.
+     * symbol pin or all graphical lines connected to \a aSegement.
+     *
+     * @note This only works for line segments.  It will need to be modified for connected arcs and/or
+     *       Bezier curves.
      *
      * @param aSegment The segment to test for connections.
+     * @return a set of all #SCH_ITEM objects connected to \a aSegment.
      */
     std::set<SCH_ITEM*> MarkConnections( SCH_LINE* aSegment, bool aSecondPass );
 

eeschema/sch_shape.cpp

@@ -137,6 +137,17 @@ bool SCH_SHAPE::HitTest( const BOX2I& aRect, bool aContained, int aAccuracy ) co
 }
 
 
+bool SCH_SHAPE::IsEndPoint( const VECTOR2I& aPt ) const
+{
+    SHAPE_T shape = GetShape();
+
+    if( ( shape == SHAPE_T::ARC ) || ( shape == SHAPE_T::BEZIER ) )
+        return ( aPt == GetStart() ) || ( aPt == GetEnd() );
+
+    return false;
+}
+
+
 void SCH_SHAPE::Plot( PLOTTER* aPlotter, bool aBackground, const SCH_PLOT_OPTS& aPlotOpts,
                       int aUnit, int aBodyStyle, const VECTOR2I& aOffset, bool aDimmed )
 {

eeschema/sch_shape.h

@@ -50,6 +50,8 @@ public:
     bool HitTest( const VECTOR2I& aPosition, int aAccuracy = 0 ) const override;
     bool HitTest( const BOX2I& aRect, bool aContained, int aAccuracy = 0 ) const override;
 
+    bool IsEndPoint( const VECTOR2I& aPoint ) const override;
+
     int GetPenWidth() const override                  { return GetStroke().GetWidth(); }
 
     bool HasLineStroke() const override               { return true; }

eeschema/tools/sch_selection_tool.cpp

@@ -2260,8 +2260,6 @@ int SCH_SELECTION_TOOL::SelectConnection( const TOOL_EVENT& aEvent )
     if( m_selection.Empty() )
         return 0;
 
-    unsigned  done = false;
-
     m_frame->GetScreen()->ClearDrawingState();
 
     for( EDA_ITEM* selItem : m_selection.GetItems() )
@@ -2271,26 +2269,10 @@ int SCH_SELECTION_TOOL::SelectConnection( const TOOL_EVENT& aEvent )
 
         SCH_LINE* line = static_cast<SCH_LINE*>( selItem );
 
-        std::set<SCH_ITEM*> conns = m_frame->GetScreen()->MarkConnections( line, false );
+        std::set<SCH_ITEM*> conns = m_frame->GetScreen()->MarkConnections( line, line->IsConnectable() );
+
         for( SCH_ITEM* item : conns )
-        {
-            if( item->IsType( { SCH_ITEM_LOCATE_WIRE_T, SCH_ITEM_LOCATE_BUS_T,
-                                SCH_ITEM_LOCATE_GRAPHIC_LINE_T } )
-                && !item->IsSelected() )
-            {
-                done = true;
-            }
-
             select( item );
-        }
-
-        if( !done )
-        {
-            conns = m_frame->GetScreen()->MarkConnections( line, true );
-
-            for( SCH_ITEM* item : conns )
-                select( item );
-        }
     }
 
     if( m_selection.GetSize() > 1 )
@@ -2869,5 +2851,3 @@ void SCH_SELECTION_TOOL::setTransitions()
 
     Go( &SCH_SELECTION_TOOL::disambiguateCursor,  EVENTS::DisambiguatePoint );
 }
-
-