[gtk/matthiasc/for-master: 4/4] print backend: Fix list model handling in dispose

[Matthias Clasen <matthiasc src gnome org>]

commit 843999265b89def9e85baabcf1ad93738fa7fa55
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Jun 1 07:43:54 2020 -0400

    print backend: Fix list model handling in dispose
    
    The print backends do some complicated dispose handling
    where the implementations call gtk_print_backend_destroy().
    
    Our tests (in particular, the templates test) trigger
    situations where we use print backends after dispose,
    and they can't handle the printers listmodel being
    NULL at that time. So just remove the printers in
    dispose, keep the empty liststore until finalize.

 gtk/gtkprintbackend.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkprintbackend.c b/gtk/gtkprintbackend.c
index eadd4125d5..2071379a1b 100644
--- a/gtk/gtkprintbackend.c
+++ b/gtk/gtkprintbackend.c
@@ -29,6 +29,7 @@
 #include "gtkprintbackendprivate.h"
 
 
+static void gtk_print_backend_finalize     (GObject      *object);
 static void gtk_print_backend_dispose      (GObject      *object);
 static void gtk_print_backend_set_property (GObject      *object,
                                             guint         prop_id,
@@ -251,6 +252,7 @@ gtk_print_backend_class_init (GtkPrintBackendClass *class)
 
   backend_parent_class = g_type_class_peek_parent (class);
   
+  object_class->finalize = gtk_print_backend_finalize;
   object_class->dispose = gtk_print_backend_dispose;
   object_class->set_property = gtk_print_backend_set_property;
   object_class->get_property = gtk_print_backend_get_property;
@@ -348,11 +350,21 @@ gtk_print_backend_dispose (GObject *object)
   /* We unref the printers in dispose, not in finalize so that
    * we can break refcount cycles with gtk_print_backend_destroy 
    */
-  g_clear_object (&priv->printers);
+  g_list_store_remove_all (priv->printers);
 
   backend_parent_class->dispose (object);
 }
 
+static void
+gtk_print_backend_finalize (GObject *object)
+{
+  GtkPrintBackend *backend = GTK_PRINT_BACKEND (object);
+  GtkPrintBackendPrivate *priv = backend->priv;
+
+  g_clear_object (&priv->printers);
+
+  backend_parent_class->finalize (object);
+}
 
 static void
 fallback_printer_request_details (GtkPrinter *printer)
@@ -361,7 +373,7 @@ fallback_printer_request_details (GtkPrinter *printer)
 
 static gboolean
 fallback_printer_mark_conflicts (GtkPrinter          *printer,
-                                GtkPrinterOptionSet *options)
+                                 GtkPrinterOptionSet *options)
 {
   return FALSE;
 }