Fix BreakWire tool

Adds ability to start new commit to eeschema, allowing all
AddItemsToUndoList to always append without foreknowledge.  Keeps newly
split wires on the tool until placed

Fixes https://gitlab.com/kicad/code/kicad/issues/7512

eeschema/bus-wire-junction.cpp

@@ -295,12 +295,6 @@ bool SCH_EDIT_FRAME::SchematicCleanUp( SCH_SCREEN* aScreen )
 bool SCH_EDIT_FRAME::BreakSegment( SCH_LINE* aSegment, const wxPoint& aPoint,
                                    SCH_LINE** aNewSegment, SCH_SCREEN* aScreen )
 {
-    if( !IsPointOnSegment( aSegment->GetStartPoint(), aSegment->GetEndPoint(), aPoint )
-            || aSegment->IsEndPoint( aPoint ) )
-    {
-        return false;
-    }
-
     if( aScreen == nullptr )
         aScreen = GetScreen();
 
@@ -331,7 +325,6 @@ bool SCH_EDIT_FRAME::BreakSegments( const wxPoint& aPoint, SCH_SCREEN* aScreen )
 
     bool                   brokenSegments = false;
     std::vector<SCH_LINE*> wires;
-    EDA_RECT               bbox( aPoint, wxSize( 2, 2 ) );
 
     for( auto item : aScreen->Items().Overlapping( SCH_LINE_T, aPoint ) )
     {

eeschema/ee_collectors.cpp

@@ -71,6 +71,33 @@ const KICAD_T EE_COLLECTOR::SheetsOnly[] = {
 };
 
 
+const KICAD_T EE_COLLECTOR::MovableItems[] =
+{
+    SCH_MARKER_T,
+    SCH_JUNCTION_T,
+    SCH_NO_CONNECT_T,
+    SCH_BUS_BUS_ENTRY_T,
+    SCH_BUS_WIRE_ENTRY_T,
+    SCH_LINE_T,
+    SCH_BITMAP_T,
+    SCH_TEXT_T,
+    SCH_LABEL_T,
+    SCH_GLOBAL_LABEL_T,
+    SCH_HIER_LABEL_T,
+    SCH_FIELD_T,
+    SCH_COMPONENT_T,
+    SCH_SHEET_PIN_T,
+    SCH_SHEET_T,
+    EOT
+};
+
+
+const KICAD_T EE_COLLECTOR::WiresOnly[] = {
+    SCH_LINE_T,
+    EOT
+};
+
+
 const KICAD_T EE_COLLECTOR::FieldOwners[] = {
     SCH_COMPONENT_T,
     SCH_SHEET_T,

eeschema/ee_collectors.h

@@ -44,8 +44,10 @@ class EE_COLLECTOR : public COLLECTOR
 public:
     static const KICAD_T AllItems[];
     static const KICAD_T EditableItems[];
+    static const KICAD_T MovableItems[];
     static const KICAD_T ComponentsOnly[];
     static const KICAD_T SheetsOnly[];
+    static const KICAD_T WiresOnly[];
     static const KICAD_T FieldOwners[];
 
     EE_COLLECTOR( const KICAD_T* aScanTypes = EE_COLLECTOR::AllItems ) :

eeschema/sch_edit_frame.h

@@ -756,6 +756,11 @@ public:
 
     /* Undo - redo */
 
+    /**
+     * Create a new, blank stack for future Undo commands to be pushed to
+     */
+    void StartNewUndo();
+
     /**
      * Create a copy of the current schematic item, and put it in the undo list.
      *

eeschema/schematic_undo_redo.cpp

@@ -95,6 +95,13 @@
  * swapped data is data modified by editing, so not all values are swapped
  */
 
+void SCH_EDIT_FRAME::StartNewUndo()
+{
+	PICKED_ITEMS_LIST* blank = new PICKED_ITEMS_LIST();
+	PushCommandToUndoList( blank );
+}
+
+
 void SCH_EDIT_FRAME::SaveCopyInUndoList( SCH_SCREEN*    aScreen,
                                          SCH_ITEM*      aItem,
                                          UNDO_REDO      aCommandType,
@@ -107,8 +114,13 @@ void SCH_EDIT_FRAME::SaveCopyInUndoList( SCH_SCREEN*    aScreen,
     // Connectivity may change
     aItem->SetConnectivityDirty();
 
-    if( aAppend )
-        commandToUndo = PopCommandFromUndoList();
+	PICKED_ITEMS_LIST* lastUndo = PopCommandFromUndoList();
+
+	// If the last stack was empty, use that one instead of creating a new stack
+    if( aAppend || !lastUndo->GetCount() )
+        commandToUndo = lastUndo;
+    else
+    	PushCommandToUndoList( lastUndo );
 
     if( !commandToUndo )
     {

eeschema/tools/sch_edit_tool.cpp

@@ -66,6 +66,8 @@
 #include <dialogs/dialog_edit_label.h>
 #include <core/kicad_algo.h>
 
+#include <limits>
+
 class SYMBOL_UNIT_MENU : public ACTION_MENU
 {
 public:
@@ -1685,10 +1687,28 @@ int SCH_EDIT_TOOL::ChangeTextType( const TOOL_EVENT& aEvent )
 
 int SCH_EDIT_TOOL::BreakWire( const TOOL_EVENT& aEvent )
 {
-    auto cursorPos = wxPoint( getViewControls()->GetCursorPosition( !aEvent.Modifier( MD_ALT ) ) );
+    wxPoint cursorPos = wxPoint( getViewControls()->GetCursorPosition( !aEvent.Modifier( MD_ALT ) ) );
+    EE_SELECTION& selection = m_selectionTool->RequestSelection( EE_COLLECTOR::WiresOnly );
 
-    if( m_frame->BreakSegments( cursorPos ) )
+    std::vector<SCH_LINE*> lines;
+
+    for( auto& item : selection )
     {
+    	if( SCH_LINE* line = dyn_cast<SCH_LINE*>( item ) )
+		{
+    		if( !line->IsEndPoint( cursorPos ) )
+    		lines.push_back( line );
+		}
+    }
+
+    m_selectionTool->ClearSelection();
+	m_frame->StartNewUndo();
+
+	for( SCH_LINE* line : lines )
+		m_frame->BreakSegment( line,  cursorPos );
+
+	if( !lines.empty() )
+	{
         if( m_frame->GetScreen()->IsJunctionNeeded( cursorPos, true ) )
             m_frame->AddJunction( m_frame->GetScreen(), cursorPos, true, false );
 
@@ -1696,6 +1716,8 @@ int SCH_EDIT_TOOL::BreakWire( const TOOL_EVENT& aEvent )
 
         m_frame->OnModify();
         m_frame->GetCanvas()->Refresh();
+
+        m_toolMgr->RunAction( EE_ACTIONS::drag );
     }
 
     return 0;

eeschema/tools/sch_move_tool.cpp

@@ -81,27 +81,6 @@ bool SCH_MOVE_TOOL::Init()
 }
 
 
-static const KICAD_T movableItems[] =
-{
-    SCH_MARKER_T,
-    SCH_JUNCTION_T,
-    SCH_NO_CONNECT_T,
-    SCH_BUS_BUS_ENTRY_T,
-    SCH_BUS_WIRE_ENTRY_T,
-    SCH_LINE_T,
-    SCH_BITMAP_T,
-    SCH_TEXT_T,
-    SCH_LABEL_T,
-    SCH_GLOBAL_LABEL_T,
-    SCH_HIER_LABEL_T,
-    SCH_FIELD_T,
-    SCH_COMPONENT_T,
-    SCH_SHEET_PIN_T,
-    SCH_SHEET_T,
-    EOT
-};
-
-
 /* TODO - Tom/Jeff
   - add preferences option "Move origin: always cursor / item origin"
   - add preferences option "Default drag action: drag items / move"
@@ -150,7 +129,7 @@ int SCH_MOVE_TOOL::Main( const TOOL_EVENT& aEvent )
 
     // Be sure that there is at least one item that we can move. If there's no selection try
     // looking for the stuff under mouse cursor (i.e. Kicad old-style hover selection).
-    EE_SELECTION& selection = m_selectionTool->RequestSelection( movableItems );
+    EE_SELECTION& selection = m_selectionTool->RequestSelection( EE_COLLECTOR::MovableItems );
     bool          unselect = selection.IsHover();
 
     // Keep an original copy of the starting points for cleanup after the move
@@ -751,7 +730,7 @@ void SCH_MOVE_TOOL::moveItem( EDA_ITEM* aItem, const VECTOR2I& aDelta )
 int SCH_MOVE_TOOL::AlignElements( const TOOL_EVENT& aEvent )
 {
     EE_GRID_HELPER grid( m_toolMgr);
-    EE_SELECTION& selection = m_selectionTool->RequestSelection( movableItems );
+    EE_SELECTION& selection = m_selectionTool->RequestSelection( EE_COLLECTOR::MovableItems );
     bool append_undo = false;
 
     for( SCH_ITEM* it : m_frame->GetScreen()->Items() )