Fixed #951

The problem was essentially the "specific path" which got invalid.
The solution is to establish a better criterion for "path validity"
and use for failsafes against invalid paths.

In addition, the path validation has been modified such that a
better choice is made about the remaining path after a cell gets
deleted.

src/laybasic/laybasic/layCellView.cc

@@ -501,13 +501,13 @@ CellView::is_valid () const
   }
 
   //  check, if the path references valid cell indices.
-  for (specific_cell_path_type::const_iterator pp = m_specific_path.begin (); pp != m_specific_path.end (); ++pp) {
-    if (! m_layout_href.get ()->layout ().is_valid_cell_index (pp->inst_ptr.cell_index ())) {
+  for (unspecific_cell_path_type::const_iterator pp = m_unspecific_path.begin (); pp != m_unspecific_path.end (); ++pp) {
+    if (! m_layout_href.get ()->layout ().is_valid_cell_index (*pp)) {
       return false;
     }
   }
-  for (unspecific_cell_path_type::const_iterator pp = m_unspecific_path.begin (); pp != m_unspecific_path.end (); ++pp) {
-    if (! m_layout_href.get ()->layout ().is_valid_cell_index (*pp)) {
+  for (specific_cell_path_type::const_iterator pp = m_specific_path.begin (); pp != m_specific_path.end (); ++pp) {
+    if (! pp->inst_ptr.instances () || ! pp->inst_ptr.instances ()->is_valid (pp->inst_ptr) || ! m_layout_href.get ()->layout ().is_valid_cell_index (pp->inst_ptr.cell_index ())) {
       return false;
     }
   }

src/laybasic/laybasic/layHierarchyControlPanel.cc

@@ -836,6 +836,8 @@ HierarchyControlPanel::do_update_content (int cv_index)
     if (&m_cellviews [i]->layout () != &mp_view->cellview (i)->layout ()) {
       m_needs_update [i] = true;
       m_force_close [i] = true;
+    } else if (! m_cellviews [i].is_valid ()) {
+      m_needs_update [i] = true;
     } else if (m_cellviews [i].combined_unspecific_path () != mp_view->cellview (i).combined_unspecific_path ()) {
       m_needs_update [i] = true;
     }

src/laybasic/laybasic/layLayoutView.cc

@@ -4896,6 +4896,7 @@ LayoutView::select_cell_fit (const cell_path_type &path, int index)
 
     set_min_hier_levels (0);
     cancel (); 
+    cellview_iter (index)->set_specific_path (lay::CellView::specific_cell_path_type ());
     cellview_iter (index)->set_unspecific_path (path);
     set_active_cellview_index (index);
     redraw ();
@@ -4985,6 +4986,7 @@ LayoutView::select_cell (const cell_path_type &path, int index)
 
     set_min_hier_levels (0);
     cancel (); 
+    cellview_iter (index)->set_specific_path (lay::CellView::specific_cell_path_type ());
     cellview_iter (index)->set_unspecific_path (path);
     set_active_cellview_index (index);
     redraw ();

src/laybasic/laybasic/layLayoutViewFunctions.cc

@@ -42,6 +42,41 @@
 namespace lay
 {
 
+static void
+collect_cells_to_delete (const db::Layout &layout, const db::Cell &cell, std::set<db::cell_index_type> &called)
+{
+  //  don't delete proxies - they are deleted later when the layout is cleaned
+  for (db::Cell::child_cell_iterator cc = cell.begin_child_cells (); ! cc.at_end (); ++cc) {
+    if (called.find (*cc) == called.end () && !layout.cell (*cc).is_proxy ()) {
+      called.insert (*cc);
+      collect_cells_to_delete (layout, layout.cell (*cc), called);
+    }
+  }
+}
+
+static bool
+validate_cell_path (const db::Layout &layout, lay::LayoutView::cell_path_type &path)
+{
+  for (size_t i = 0; i < path.size (); ++i) {
+
+    if (! layout.is_valid_cell_index (path [i])) {
+
+      if (layout.is_valid_cell_index (path.back ())) {
+        //  use a stub path
+        path.erase (path.begin (), --path.end ());
+      } else {
+        //  strip everything that is not valid
+        path.erase (path.begin () + i, path.end ());
+      }
+
+      return true;
+
+    }
+  }
+
+  return false;
+}
+
 LayoutViewFunctions::LayoutViewFunctions (db::Manager *manager, LayoutView *view)
   : lay::Plugin (view), mp_view (view), mp_manager (manager)
 {
@@ -493,18 +528,7 @@ LayoutViewFunctions::cm_cell_replace ()
 
         view ()->commit ();
 
-        //  If one of the cells in the path was deleted, establish a valid path
-
-        bool needs_update = false;
-        for (size_t i = cell_path.size (); i > 0; ) {
-          --i;
-          if (! layout.is_valid_cell_index (cell_path [i])) {
-            cell_path.erase (cell_path.begin () + i, cell_path.end ());
-            needs_update = true;
-          }
-        }
-
-        if (needs_update) {
+        if (validate_cell_path (layout, cell_path)) {
           view ()->select_cell (cell_path, cv_index);
         }
 
@@ -613,36 +637,13 @@ LayoutViewFunctions::cm_cell_convert_to_static ()
 
     view ()->commit ();
 
-    //  If one of the cells in the path was deleted, establish a valid path
-
-    bool needs_update = false;
-    for (size_t i = cell_path.size (); i > 0; ) {
-      --i;
-      if (! layout.is_valid_cell_index (cell_path [i])) {
-        cell_path.erase (cell_path.begin () + i, cell_path.end ());
-        needs_update = true;
-      }
-    }
-
-    if (needs_update) {
+    if (validate_cell_path (layout, cell_path)) {
       view ()->select_cell (cell_path, cv_index);
     }
 
   }
 }
 
-static void
-collect_cells_to_delete (const db::Layout &layout, const db::Cell &cell, std::set<db::cell_index_type> &called)
-{
-  //  don't delete proxies - they are deleted later when the layout is cleaned
-  for (db::Cell::child_cell_iterator cc = cell.begin_child_cells (); ! cc.at_end (); ++cc) {
-    if (called.find (*cc) == called.end () && !layout.cell (*cc).is_proxy ()) {
-      called.insert (*cc);
-      collect_cells_to_delete (layout, layout.cell (*cc), called);
-    }
-  }
-}
-
 void
 LayoutViewFunctions::cm_cell_delete ()
 {
@@ -704,18 +705,7 @@ LayoutViewFunctions::cm_cell_delete ()
 
       view ()->commit ();
 
-      //  If one of the cells in the path was deleted, establish a valid path
-
-      bool needs_update = false;
-      for (size_t i = cell_path.size (); i > 0; ) {
-        --i;
-        if (! layout.is_valid_cell_index (cell_path [i])) {
-          cell_path.erase (cell_path.begin () + i, cell_path.end ());
-          needs_update = true;
-        }
-      }
-
-      if (needs_update) {
+      if (validate_cell_path (layout, cell_path)) {
         view ()->select_cell (cell_path, cv_index);
       }