[gimp] app: check if an item was already inserted by actually looking it up in…

[Jehan <jehanp src gnome org>]

commit 367901875f8847b3bbadae654eb3bc805b15a39d
Author: Jehan <jehan girinstud io>
Date:   Thu Jun 10 17:44:08 2021 +0200

    app: check if an item was already inserted by actually looking it up in…
    
    … the container.
    
    There was this weird case which we somehow could only reproduce on
    Aryeom's computer/build, not mine, with the same code and reproduction
    steps (reproducible at will on her build only). Basically when drag'n
    dropping a duplicated layer inside a collapsed layer group, the
    row-expanded handler would try to select the moved layer before it is
    actually inserted. This would end up into crash-happy code.
    
    I'm still unsure of why the order of operation is different here, but
    anyway what is for sure is that the `inserting_item` boolean flag was
    not protecting much. It's not like it's an actual mutex and anyway this
    is not multi-threaded code either so this flag was mostly useless (which
    is why we were crashing). Instead let's actually look if the item is in
    the container or not.

 app/widgets/gimpitemtreeview.c | 29 ++++++++++++-----------------
 1 file changed, 12 insertions(+), 17 deletions(-)
---
diff --git a/app/widgets/gimpitemtreeview.c b/app/widgets/gimpitemtreeview.c
index 5bdf19b8b1..7d254646bc 100644
--- a/app/widgets/gimpitemtreeview.c
+++ b/app/widgets/gimpitemtreeview.c
@@ -95,8 +95,6 @@ struct _GimpItemTreeViewPrivate
 
   GimpTreeHandler *visible_changed_handler;
   GimpTreeHandler *color_tag_changed_handler;
-
-  gboolean         inserting_item; /* EEK */
 };
 
 typedef struct
@@ -1136,13 +1134,9 @@ gimp_item_tree_view_insert_item (GimpContainerView *view,
   const gchar           *icon_name;
   gint                   n_locks;
 
-  item_view->priv->inserting_item = TRUE;
-
   iter = parent_view_iface->insert_item (view, viewable,
                                          parent_insert_data, index);
 
-  item_view->priv->inserting_item = FALSE;
-
   has_color = gimp_get_color_tag_color (gimp_item_get_merged_color_tag (item),
                                         &color,
                                         gimp_item_get_color_tag (item) ==
@@ -2041,13 +2035,19 @@ gimp_item_tree_view_row_expanded (GtkTreeView      *tree_view,
                                   GtkTreePath      *path,
                                   GimpItemTreeView *item_view)
 {
+  GimpItemTreeViewClass *item_view_class;
+  GimpItem              *active_item;
+
+  item_view_class = GIMP_ITEM_TREE_VIEW_GET_CLASS (item_view);
+  active_item = item_view_class->get_active_item (item_view->priv->image);
+
   /*  don't select the item while it is being inserted  */
-  if (! item_view->priv->inserting_item)
+  if (active_item &&
+      gimp_container_view_lookup (GIMP_CONTAINER_VIEW (item_view),
+                                  GIMP_VIEWABLE (active_item)))
     {
-      GimpItemTreeViewClass *item_view_class;
-      GimpViewRenderer      *renderer;
-      GimpItem              *expanded_item;
-      GimpItem              *active_item;
+      GimpViewRenderer *renderer;
+      GimpItem         *expanded_item;
 
       gtk_tree_model_get (GIMP_CONTAINER_TREE_VIEW (item_view)->model, iter,
                           GIMP_CONTAINER_TREE_STORE_COLUMN_RENDERER, &renderer,
@@ -2055,15 +2055,10 @@ gimp_item_tree_view_row_expanded (GtkTreeView      *tree_view,
       expanded_item = GIMP_ITEM (renderer->viewable);
       g_object_unref (renderer);
 
-      item_view_class = GIMP_ITEM_TREE_VIEW_GET_CLASS (item_view);
-
-      active_item = item_view_class->get_active_item (item_view->priv->image);
-
       /*  select the active item only if it was made visible by expanding
        *  its immediate parent. See bug #666561.
        */
-      if (active_item &&
-          gimp_item_get_parent (active_item) == expanded_item)
+      if (gimp_item_get_parent (active_item) == expanded_item)
         {
           gimp_container_view_select_item (GIMP_CONTAINER_VIEW (item_view),
                                            GIMP_VIEWABLE (active_item));