[evolution] Bug 770494 - Accessing freed widget in e_alert_run_dialog()

[Milan Crha <mcrha src gnome org>]

commit 5894ee993a5e83808c9f1bf8bcbc70fe77a1cd1b
Author: Hans Petter Jansson <hpj cl no>
Date:   Mon Aug 29 14:04:45 2016 +0200

    Bug 770494 - Accessing freed widget in e_alert_run_dialog()

 e-util/e-alert-dialog.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)
---
diff --git a/e-util/e-alert-dialog.c b/e-util/e-alert-dialog.c
index 3225827..d972c2b 100644
--- a/e-util/e-alert-dialog.c
+++ b/e-util/e-alert-dialog.c
@@ -344,12 +344,19 @@ e_alert_run_dialog (GtkWindow *parent,
        GtkWidget *dialog;
        gint response;
        gulong signal_id = 0;
+       gulong parent_destroyed_signal_id = 0;
 
        g_return_val_if_fail (E_IS_ALERT (alert), 0);
 
        dialog = e_alert_dialog_new (parent, alert);
 
        if (parent != NULL) {
+               /* Since we'll be in a nested main loop, the widgets may be destroyed
+                * before we get back from gtk_dialog_run(). In practice, this can happen
+                * if Evolution exits while the dialog is up. Make sure we don't try
+                * to access destroyed widgets. */
+               parent_destroyed_signal_id = g_signal_connect (parent, "destroy", G_CALLBACK 
(gtk_widget_destroyed), &parent);
+
                gtk_window_set_urgency_hint (parent, TRUE);
                signal_id = g_signal_connect (
                        dialog, "focus-in-event",
@@ -358,14 +365,21 @@ e_alert_run_dialog (GtkWindow *parent,
                gtk_window_set_urgency_hint (GTK_WINDOW (dialog), TRUE);
        }
 
+       g_signal_connect (dialog, "destroy", G_CALLBACK (gtk_widget_destroyed), &dialog);
+
        response = gtk_dialog_run (GTK_DIALOG (dialog));
 
        if (signal_id > 0) {
-               gtk_window_set_urgency_hint (parent, FALSE);
-               g_signal_handler_disconnect (dialog, signal_id);
+               if (parent)
+                       gtk_window_set_urgency_hint (parent, FALSE);
+               if (dialog)
+                       g_signal_handler_disconnect (dialog, signal_id);
        }
 
-       gtk_widget_destroy (dialog);
+       if (dialog)
+               gtk_widget_destroy (dialog);
+       if (parent && parent_destroyed_signal_id)
+               g_signal_handler_disconnect (parent, parent_destroyed_signal_id);
 
        return response;
 }