[glib] GSettings: fix check for delaying backend subscription

[Lars Uebernickel <larsu src gnome org>]

commit d511d6b37f051d2cd8698055cbd85ee7f987325d
Author: Lars Uebernickel <lars uebernickel canonical com>
Date:   Fri Nov 28 13:06:04 2014 +0100

    GSettings: fix check for delaying backend subscription
    
    g_settings_has_signal_handlers() checks whether any of the signals has
    pending handlers. However, g_signal_has_handler_pending() matches on
    exact detail, even when passing 0. Subscribing to one of GSettings'
    signals with a detail will fail this check and never connect to the
    backend.
    
    Fix this by calling has_handler_pending() with the key as detail as
    well.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=740848

 gio/gsettings.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/gio/gsettings.c b/gio/gsettings.c
index fb2ce25..23a14bc 100644
--- a/gio/gsettings.c
+++ b/gio/gsettings.c
@@ -317,18 +317,24 @@ g_settings_real_writable_change_event (GSettings *settings,
 }
 
 static gboolean
-g_settings_has_signal_handlers (GSettings *settings)
+g_settings_has_signal_handlers (GSettings   *settings,
+                                const gchar *key)
 {
   GSettingsClass *class = G_SETTINGS_GET_CLASS (settings);
+  GQuark keyq;
 
   if (class->change_event != g_settings_real_change_event ||
       class->writable_change_event != g_settings_real_writable_change_event)
     return TRUE;
 
+  keyq = g_quark_from_string (key);
+
   if (g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_WRITABLE_CHANGE_EVENT], 0, TRUE) ||
       g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_WRITABLE_CHANGED], 0, TRUE) ||
+      g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_WRITABLE_CHANGED], keyq, TRUE) ||
       g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_CHANGE_EVENT], 0, TRUE) ||
-      g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_CHANGED], 0, TRUE))
+      g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_CHANGED], 0, TRUE) ||
+      g_signal_has_handler_pending (settings, g_settings_signals[SIGNAL_CHANGED], keyq, TRUE))
     return TRUE;
 
   /* None of that?  Then surely nobody is watching.... */
@@ -1078,7 +1084,7 @@ g_settings_read_from_backend (GSettings          *settings,
   gchar *path;
 
   /* If we are not yet watching for changes, consider doing it now... */
-  if (!settings->priv->is_subscribed && g_settings_has_signal_handlers (settings))
+  if (!settings->priv->is_subscribed && g_settings_has_signal_handlers (settings, key->name))
     {
       g_settings_backend_subscribe (settings->priv->backend, settings->priv->path);
       settings->priv->is_subscribed = TRUE;