Merge lp:~jamesh/whoopsie-preferences/bug-1720331 into lp:whoopsie-preferences

[James Henstridge]

Don't export object on the bus until it has been fully constructed.

Don't export object on the bus until it has been fully constructed.

As well as ensuring that the WhoopsiePreferences object is usable as soon as it attaches to the bus, it also silences a PropertiesChanged signal broadcast during startup as whoopsie-preferences reads the current system configuration.

This helps avoid confusion when whoopsie-preferences is activated by one of the Set method calls. For example, the following chain of events:

 1. C->S SetReportCrashes(true) method call
 2. dbus-daemon activates whoopsie-preferences
 3. S->C PropertiesChanged(ReportCrashes=true) signal with current state
 4. S->C SetReportCrashes method return message
 5. S->C PropertiesChanged(ReportCrashes=false) signal with new state

Here, the first signal broadcast at (3) is unwanted, and can confuse the client into thinking that its change has been ignored or some other client has changed the state.

By setting the initial values for the properties before exporting on the bus, the initial signal broadcast is avoided.

[James Henstridge (jamesh)]

The difference can be demonstrated by running the following command in one terminal:

    sudo dbus-monitor --system 'interface=com.ubuntu.WhoopsiePreferences' 'interface=org.freedesktop.DBus.Properties,arg0=com.ubuntu.WhoopsiePreferences'

And then in another terminal compare starting the old version of whoopsie-preferences vs. the version from this branch. The spurious signal is gone.

Using d-feet to call SetReportCrashes shows that PropertiesChanged is still sent when a change actually happens though.

=== modified file 'configure.ac'
--- configure.ac	2014-04-01 11:31:55 +0000
+++ configure.ac	2017-10-11 10:57:52 +0000
@@ -1,5 +1,5 @@
 AC_INIT([whoopsie-preferences], 
-        [0.11], 
+        [0.19], 
         [http://launchpad.net/whoopsie-preferences])
 
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
=== modified file 'debian/changelog'
--- debian/changelog	2015-09-10 14:00:51 +0000
+++ debian/changelog	2017-10-11 10:57:52 +0000
@@ -1,3 +1,17 @@
+whoopsie-preferences (0.19) artful; urgency=medium
+
+  * Don't export object on the bus until it has been fully constructed.
+    (LP: #1720331)
+
+ -- James Henstridge <[e-mail]>  Wed, 11 Oct 2017 18:20:35 +0800
+
+whoopsie-preferences (0.18build1) artful; urgency=medium
+
+  * No-change rebuild to pick up -fPIE compiler default in static
+    libraries
+
+ -- Steve Langasek <[e-mail]>  Fri, 21 Apr 2017 20:59:50 +0000
+
 whoopsie-preferences (0.18) wily; urgency=medium
 
   * Truncate the file manually if update-rc.d fails (e.g. on an r/o phone).
 
=== modified file 'src/whoopsie-preferences.c'
--- src/whoopsie-preferences.c	2015-09-10 13:19:51 +0000
+++ src/whoopsie-preferences.c	2017-10-11 10:57:52 +0000
@@ -487,18 +487,6 @@
     WhoopsiePreferences* interface;
     GError* error = NULL;
 
-    interface = whoopsie_preferences_skeleton_new ();
-    if (!g_dbus_interface_skeleton_export (
-                G_DBUS_INTERFACE_SKELETON (interface),
-                connection,
-                "/com/ubuntu/WhoopsiePreferences", &error)) {
-
-        g_print ("Could not export path: %s\n", error->message);
-        g_error_free (error);
-        g_main_loop_quit (loop);
-        return;
-    }
-
     authority = polkit_authority_get_sync (NULL, &error);
     if (authority == NULL) {
         g_print ("Could not get authority: %s\n", error->message);
@@ -509,6 +497,7 @@
     loop_shutdown = g_timeout_add_seconds (60, (GSourceFunc) g_main_loop_quit,
                                            loop);
 
+    interface = whoopsie_preferences_skeleton_new ();
     g_signal_connect (interface, "notify::report-crashes",
                       G_CALLBACK (whoopsie_preferences_changed),
                       "report_crashes");
@@ -535,6 +524,17 @@
     monitor_autoreport_file (interface);
     whoopsie_preferences_load (interface);
     whoopsie_preferences_dbus_notify (interface);
+
+    if (!g_dbus_interface_skeleton_export (
+                G_DBUS_INTERFACE_SKELETON (interface),
+                connection,
+                "/com/ubuntu/WhoopsiePreferences", &error)) {
+
+        g_print ("Could not export path: %s\n", error->message);
+        g_error_free (error);
+        g_main_loop_quit (loop);
+        return;
+    }
 }
 
 static void