eeschema: fix use-after-free crash in GetScreen()/GetCurrentSheet()

eeschema/files-io.cpp

@@ -239,7 +239,9 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
     {
         SetScreen( nullptr );
         delete g_RootSheet;
-        g_RootSheet = NULL;
+        if( g_CurrentSheet )
+            g_CurrentSheet->clear();
+        g_RootSheet = nullptr;
 
         CreateScreens();
     }

eeschema/sch_edit_frame.cpp

@@ -489,12 +489,18 @@ void SCH_EDIT_FRAME::SetSheetNumberAndCount()
 
 SCH_SCREEN* SCH_EDIT_FRAME::GetScreen() const
 {
+    if( !g_CurrentSheet )
+        return nullptr;
+
     return g_CurrentSheet->LastScreen();
 }
 
 
 wxString SCH_EDIT_FRAME::GetScreenDesc() const
 {
+    if(! g_CurrentSheet )
+        return wxT("<unknown>");
+
     wxString s = g_CurrentSheet->PathHumanReadable();
 
     return s;
@@ -748,8 +754,12 @@ void SCH_EDIT_FRAME::OnUpdateRemapSymbols( wxUpdateUIEvent& aEvent )
 
 void SCH_EDIT_FRAME::OnUpdateSaveSheet( wxUpdateUIEvent& aEvent )
 {
-    aEvent.Enable( GetScreen()->IsModify() );
+    auto screen = GetScreen();
+
+    if( !screen )
+        return;
 
+    aEvent.Enable( screen->IsModify() );
 }
 
 

eeschema/tools/sch_move_tool.cpp

@@ -125,9 +125,9 @@ int SCH_MOVE_TOOL::Main( const TOOL_EVENT& aEvent )
     };
 
     KIGFX::VIEW_CONTROLS* controls = getViewControls();
-
     controls->SetSnapping( true );
     VECTOR2I originalCursorPos = controls->GetCursorPosition();
+    bool moveMode;
 
     // 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).
@@ -463,7 +463,6 @@ void SCH_MOVE_TOOL::getConnectedDragItems( SCH_ITEM* aOriginalItem, wxPoint aPoi
 
         switch( test->Type() )
         {
-        default:
         case SCH_LINE_T:
         {
             // Select the connected end of wires/bus connections.