[gtk/fix-can-focus] widget: Fix can-focus

[Matthias Clasen <matthiasc src gnome org>]

commit 8ef1d6a49ca2955d152e67012f79b9ad5cc73a37
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jan 26 23:43:11 2021 -0500

    widget: Fix can-focus
    
    Setting can-focus to FALSE on a widget is supposed
    to prevent focus from entering the entire subtree.
    So when we grab focus directly to a widget, we need
    to check the can-focus flag not just of the widget
    itself, but all its ancestors.
    
    Fixes: #3610

 gtk/gtkwidget.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 0daeef7a6d..0186968bd7 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -4390,13 +4390,27 @@ gtk_widget_can_activate (GtkWidget *self)
   return FALSE;
 }
 
+static gboolean
+get_effective_can_focus (GtkWidget *widget)
+{
+  GtkWidgetPrivate *priv = gtk_widget_get_instance_private (widget);
+
+  if (!priv->can_focus)
+    return FALSE;
+
+  if (priv->parent)
+    return get_effective_can_focus (priv->parent);
+
+  return TRUE;
+}
+
 static gboolean
 gtk_widget_real_mnemonic_activate (GtkWidget *widget,
                                    gboolean   group_cycling)
 {
   if (!group_cycling && gtk_widget_can_activate (widget))
     gtk_widget_activate (widget);
-  else if (gtk_widget_get_can_focus (widget))
+  else if (get_effective_can_focus (widget))
     return gtk_widget_grab_focus (widget);
   else
     {
@@ -4782,7 +4796,7 @@ gtk_widget_grab_focus (GtkWidget *widget)
   g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
 
   if (!gtk_widget_is_sensitive (widget) ||
-      !gtk_widget_get_can_focus (widget) ||
+      !get_effective_can_focus (widget) ||
       widget->priv->root == NULL)
     return FALSE;