[gtk/teardown-cleanup-2: 29/30] treeview: Break reference cycles on unroot

[Matthias Clasen <matthiasc src gnome org>]

commit d061bcad52d392664b4291eeebc4b42e9b8116d7
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon May 11 10:00:12 2020 -0400

    treeview: Break reference cycles on unroot
    
    It is a bad idea to have such cycles in the first place,
    and there is no need to let them linger past unroot.
    
    This stop the treeview depending on run_dispose to get
    freed, a simple unparent will work now.

 gtk/gtktreeview.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index bd5cde291a..efa2c9d712 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -644,6 +644,7 @@ static void     gtk_tree_view_get_property         (GObject         *object,
 /* gtkwidget signals */
 static void     gtk_tree_view_realize              (GtkWidget        *widget);
 static void     gtk_tree_view_unrealize            (GtkWidget        *widget);
+static void     gtk_tree_view_unroot               (GtkWidget        *widget);
 static void     gtk_tree_view_map                  (GtkWidget        *widget);
 static void     gtk_tree_view_measure              (GtkWidget        *widget,
                                                     GtkOrientation  orientation,
@@ -1021,6 +1022,7 @@ gtk_tree_view_class_init (GtkTreeViewClass *class)
   widget_class->map = gtk_tree_view_map;
   widget_class->realize = gtk_tree_view_realize;
   widget_class->unrealize = gtk_tree_view_unrealize;
+  widget_class->unroot = gtk_tree_view_unroot;
   widget_class->measure = gtk_tree_view_measure;
   widget_class->size_allocate = gtk_tree_view_size_allocate;
   widget_class->snapshot = gtk_tree_view_snapshot;
@@ -2311,6 +2313,19 @@ gtk_tree_view_unrealize (GtkWidget *widget)
   GTK_WIDGET_CLASS (gtk_tree_view_parent_class)->unrealize (widget);
 }
 
+static void
+gtk_tree_view_unroot (GtkWidget *widget)
+{
+  GtkTreeView *tree_view = GTK_TREE_VIEW (widget);
+
+  /* break ref cycles */
+  g_clear_pointer (&tree_view->scroll_to_path, gtk_tree_row_reference_free);
+  g_clear_pointer (&tree_view->drag_dest_row, gtk_tree_row_reference_free);
+  g_clear_pointer (&tree_view->top_row, gtk_tree_row_reference_free);
+
+  GTK_WIDGET_CLASS (gtk_tree_view_parent_class)->unroot (widget);
+}
+
 /* GtkWidget::get_preferred_height helper */
 static void
 gtk_tree_view_update_height (GtkTreeView *tree_view)