printers: Use g_autoptr for GError handling

11 files changed, 249 insertions, 364 deletions

diff --git a/panels/printers/cc-printers-panel.c b/panels/printers/cc-printers-panel.c
index f05a3ec6d..a2566a022 100644
--- a/panels/printers/cc-printers-panel.c
+++ b/panels/printers/cc-printers-panel.c
@@ -269,16 +269,13 @@ printer_removed_cb (GObject      *source_object,
                     GAsyncResult *result,
                     gpointer      user_data)
 {
-  GError *error = NULL;
+  g_autoptr(GError) error = NULL;
 
   pp_printer_delete_finish (PP_PRINTER (source_object), result, &error);
   g_object_unref (source_object);
 
   if (error != NULL)
-    {
-      g_warning ("Printer could not be deleted: %s", error->message);
-      g_error_free (error);
-    }
+    g_warning ("Printer could not be deleted: %s", error->message);
 }
 
 static void
@@ -416,7 +413,7 @@ on_get_job_attributes_cb (GObject      *source_object,
   GVariant               *attributes;
   GVariant               *username;
   GVariant               *printer_uri;
-  GError                 *error = NULL;
+  g_autoptr(GError)       error = NULL;
 
   priv = PRINTERS_PANEL_PRIVATE (self);
 
@@ -595,7 +592,7 @@ attach_to_cups_notifier_cb (GObject      *source_object,
   CcPrintersPanelPrivate *priv;
   CcPrintersPanel        *self = (CcPrintersPanel*) user_data;
   PpCups                 *cups = PP_CUPS (source_object);
-  GError                 *error = NULL;
+  g_autoptr(GError)       error = NULL;
   gint                    subscription_id;
 
   subscription_id = pp_cups_renew_subscription_finish (cups, result);
@@ -621,7 +618,6 @@ attach_to_cups_notifier_cb (GObject      *source_object,
       if (!priv->cups_proxy)
         {
           g_warning ("%s", error->message);
-          g_error_free (error);
           return;
         }
 
@@ -921,7 +917,7 @@ actualize_printers_list_cb (GObject      *source_object,
   PpCups                 *cups = PP_CUPS (source_object);
   PpCupsDests            *cups_dests;
   gboolean                new_printer_available = FALSE;
-  GError                 *error = NULL;
+  g_autoptr(GError)       error = NULL;
   int                     i;
 
   cups_dests = pp_cups_get_dests_finish (cups, result, &error);
@@ -933,7 +929,6 @@ actualize_printers_list_cb (GObject      *source_object,
           g_warning ("Could not get dests: %s", error->message);
         }
 
-      g_error_free (error);
       g_object_unref (cups);
       return;
     }
@@ -1338,7 +1333,7 @@ cc_printers_panel_init (CcPrintersPanel *self)
   GtkWidget              *top_widget;
   GtkWidget              *widget;
   PpCups                 *cups;
-  GError                 *error = NULL;
+  g_autoptr(GError)       error = NULL;
   gchar                  *objects[] = { "overlay", "headerbar-buttons", "search-button", NULL };
   guint                   builder_result;
 
@@ -1392,7 +1387,6 @@ cc_printers_panel_init (CcPrintersPanel *self)
     {
       /* Translators: The XML file containing user interface can not be loaded */
       g_warning (_("Could not load ui: %s"), error->message);
-      g_error_free (error);
       return;
     }
 
diff --git a/panels/printers/pp-host.c b/panels/printers/pp-host.c
index 8af77e9a9..70b447c8c 100644
--- a/panels/printers/pp-host.c
+++ b/panels/printers/pp-host.c
@@ -251,16 +251,16 @@ _pp_host_get_snmp_devices_thread (GSimpleAsyncResult *res,
                                   GObject            *object,
                                   GCancellable       *cancellable)
 {
-  PpHost         *host = (PpHost *) object;
-  PpHostPrivate  *priv = host->priv;
-  PpPrintDevice  *device;
-  gboolean        is_network_device;
-  GSDData        *data;
-  GError         *error;
-  gchar         **argv;
-  gchar          *stdout_string = NULL;
-  gchar          *stderr_string = NULL;
-  gint            exit_status;
+  PpHost           *host = (PpHost *) object;
+  PpHostPrivate    *priv = host->priv;
+  PpPrintDevice    *device;
+  gboolean          is_network_device;
+  GSDData          *data;
+  g_autoptr(GError) error = NULL;
+  gchar           **argv;
+  gchar            *stdout_string = NULL;
+  gchar            *stderr_string = NULL;
+  gint              exit_status;
 
   data = g_simple_async_result_get_op_res_gpointer (res);
   data->devices = g_new0 (PpDevicesList, 1);
@@ -510,7 +510,7 @@ jetdirect_connection_test_cb (GObject      *source_object,
   PpPrintDevice     *device;
   JetDirectData     *data;
   gpointer           result;
-  GError            *error = NULL;
+  g_autoptr(GError)  error = NULL;
   GTask             *task = G_TASK (user_data);
 
   data = g_task_get_task_data (task);
@@ -625,7 +625,7 @@ test_lpd_queue (GSocketClient *client,
 {
   GSocketConnection *connection;
   gboolean           result = FALSE;
-  GError            *error = NULL;
+  g_autoptr(GError)  error = NULL;
 
   connection = g_socket_client_connect_to_host (client,
                                                 address,
@@ -679,14 +679,6 @@ test_lpd_queue (GSocketClient *client,
                       result = TRUE;
                     }
                 }
-              else
-                {
-                  g_clear_error (&error);
-                }
-            }
-          else
-            {
-              g_clear_error (&error);
             }
         }
 
@@ -710,7 +702,7 @@ _pp_host_get_lpd_devices_thread (GTask        *task,
   GSocketClient     *client;
   PpDevicesList     *result;
   GSDData           *data = (GSDData *) task_data;
-  GError            *error = NULL;
+  g_autoptr(GError)  error = NULL;
   GList             *candidates = NULL;
   GList             *iter;
   gchar             *found_queue = NULL;
diff --git a/panels/printers/pp-job.c b/panels/printers/pp-job.c
index 0c04c4f35..4bfa8154d 100644
--- a/panels/printers/pp-job.c
+++ b/panels/printers/pp-job.c
@@ -90,7 +90,7 @@ pp_job_cancel_purge_async (PpJob        *job,
                            gboolean      job_purge)
 {
   GDBusConnection *bus;
-  GError          *error = NULL;
+  g_autoptr(GError) error = NULL;
   gint            *job_id;
 
   g_object_get (job, "id", &job_id, NULL);
@@ -99,7 +99,6 @@ pp_job_cancel_purge_async (PpJob        *job,
   if (!bus)
     {
       g_warning ("Failed to get session bus: %s", error->message);
-      g_error_free (error);
       return;
     }
 
@@ -141,9 +140,9 @@ void
 pp_job_set_hold_until_async (PpJob        *job,
                              const gchar  *job_hold_until)
 {
-  GDBusConnection *bus;
-  GError          *error = NULL;
-  gint            *job_id;
+  GDBusConnection  *bus;
+  g_autoptr(GError) error = NULL;
+  gint             *job_id;
 
   g_object_get (job, "id", &job_id, NULL);
 
@@ -151,7 +150,6 @@ pp_job_set_hold_until_async (PpJob        *job,
   if (!bus)
     {
       g_warning ("Failed to get session bus: %s", error->message);
-      g_error_free (error);
       return;
     }
 
diff --git a/panels/printers/pp-jobs-dialog.c b/panels/printers/pp-jobs-dialog.c
index c5e9e9f02..e3956e5c8 100644
--- a/panels/printers/pp-jobs-dialog.c
+++ b/panels/printers/pp-jobs-dialog.c
@@ -317,18 +317,18 @@ update_jobs_list_cb (GObject      *source_object,
                      GAsyncResult *result,
                      gpointer      user_data)
 {
-  PpJobsDialog  *dialog = user_data;
-  PpPrinter     *printer = PP_PRINTER (source_object);
-  GtkWidget     *clear_all_button;
-  GtkWidget     *infobar;
-  GtkWidget     *label;
-  GtkStack      *stack;
-  GError        *error = NULL;
-  GList         *jobs, *l;
-  PpJob         *job;
-  gchar        **auth_info_required = NULL;
-  gchar         *text;
-  gint           num_of_jobs, num_of_auth_jobs = 0;
+  PpJobsDialog     *dialog = user_data;
+  PpPrinter        *printer = PP_PRINTER (source_object);
+  GtkWidget        *clear_all_button;
+  GtkWidget        *infobar;
+  GtkWidget        *label;
+  GtkStack         *stack;
+  g_autoptr(GError) error = NULL;
+  GList            *jobs, *l;
+  PpJob            *job;
+  gchar           **auth_info_required = NULL;
+  gchar            *text;
+  gint              num_of_jobs, num_of_auth_jobs = 0;
 
   g_list_store_remove_all (dialog->store);
 
@@ -343,7 +343,6 @@ update_jobs_list_cb (GObject      *source_object,
           g_warning ("Could not get jobs: %s", error->message);
         }
 
-      g_error_free (error);
       return;
     }
 
@@ -474,10 +473,10 @@ pp_job_authenticate_cb (GObject      *source_object,
                         GAsyncResult *res,
                         gpointer      user_data)
 {
-  PpJobsDialog *dialog = user_data;
-  gboolean      result;
-  GError       *error = NULL;
-  PpJob        *job = PP_JOB (source_object);
+  PpJobsDialog     *dialog = user_data;
+  gboolean          result;
+  g_autoptr(GError) error = NULL;
+  PpJob            *job = PP_JOB (source_object);
 
   result = pp_job_authenticate_finish (job, res, &error);
   if (result)
@@ -490,8 +489,6 @@ pp_job_authenticate_cb (GObject      *source_object,
         {
           g_warning ("Could not authenticate job: %s", error->message);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -558,13 +555,13 @@ pp_jobs_dialog_new (GtkWindow            *parent,
                     gpointer              user_data,
                     gchar                *printer_name)
 {
-  PpJobsDialog    *dialog;
-  GtkWidget       *widget;
-  GError          *error = NULL;
-  gchar           *objects[] = { "jobs-dialog", "authentication_popover", NULL };
-  gchar           *text;
-  guint            builder_result;
-  gchar           *title;
+  PpJobsDialog     *dialog;
+  GtkWidget        *widget;
+  g_autoptr(GError) error = NULL;
+  gchar            *objects[] = { "jobs-dialog", "authentication_popover", NULL };
+  gchar            *text;
+  guint             builder_result;
+  gchar            *title;
 
   dialog = g_new0 (PpJobsDialog, 1);
 
@@ -578,7 +575,6 @@ pp_jobs_dialog_new (GtkWindow            *parent,
   if (builder_result == 0)
     {
       g_warning ("Could not load ui: %s", error->message);
-      g_error_free (error);
       return NULL;
     }
 
diff --git a/panels/printers/pp-new-printer-dialog.c b/panels/printers/pp-new-printer-dialog.c
index f7cdfd8f8..77576d529 100644
--- a/panels/printers/pp-new-printer-dialog.c
+++ b/panels/printers/pp-new-printer-dialog.c
@@ -264,7 +264,7 @@ get_authenticated_samba_devices_cb (GObject      *source_object,
   GtkWidget                 *widget;
   gboolean                   cancelled = FALSE;
   PpSamba                   *samba = (PpSamba *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
   GList                     *iter;
 
   g_object_ref (samba);
@@ -324,8 +324,6 @@ get_authenticated_samba_devices_cb (GObject      *source_object,
           priv->samba_authenticated_searching = FALSE;
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 
   g_free (data->server_name);
@@ -526,7 +524,7 @@ pp_new_printer_dialog_init (PpNewPrinterDialog *dialog)
   PpNewPrinterDialogPrivate *priv;
   GtkStyleContext           *context;
   GtkWidget                 *widget;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
   gchar                     *objects[] = { "dialog",
                                            "devices-liststore",
                                            "devices-model-filter",
@@ -545,7 +543,6 @@ pp_new_printer_dialog_init (PpNewPrinterDialog *dialog)
   if (builder_result == 0)
     {
       g_warning ("Could not load ui: %s", error->message);
-      g_error_free (error);
     }
 
   /* GCancellable for cancelling of async operations */
@@ -975,10 +972,10 @@ group_physical_devices_dbus_cb (GObject      *source_object,
                                 GAsyncResult *res,
                                 gpointer      user_data)
 {
-  GVariant   *output;
-  GError     *error = NULL;
-  gchar    ***result = NULL;
-  gint        i, j;
+  GVariant         *output;
+  g_autoptr(GError) error = NULL;
+  gchar          ***result = NULL;
+  gint              i, j;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -1045,9 +1042,6 @@ DBus method \"GroupPhysicalDevices\" to group duplicates in device list.");
       error->domain != G_IO_ERROR ||
       error->code != G_IO_ERROR_CANCELLED)
     group_physical_devices_cb (result, user_data);
-
-  if (error)
-    g_error_free (error);
 }
 
 static void
@@ -1067,7 +1061,7 @@ get_cups_devices_cb (GList    *devices,
   const gchar                *device_class;
   GtkTreeIter                 iter;
   gboolean                    cont;
-  GError                     *error = NULL;
+  g_autoptr(GError)           error = NULL;
   GList                      *liter;
   gint                        length, i;
 
@@ -1183,7 +1177,6 @@ get_cups_devices_cb (GList    *devices,
               else
                 {
                   g_warning ("Failed to get system bus: %s", error->message);
-                  g_error_free (error);
                   group_physical_devices_cb (NULL, user_data);
                 }
 
@@ -1213,7 +1206,7 @@ get_snmp_devices_cb (GObject      *source_object,
   PpNewPrinterDialog        *dialog;
   PpNewPrinterDialogPrivate *priv;
   PpHost                    *host = (PpHost *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
   PpDevicesList             *result;
 
   result = pp_host_get_snmp_devices_finish (host, res, &error);
@@ -1248,8 +1241,6 @@ get_snmp_devices_cb (GObject      *source_object,
 
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1261,7 +1252,7 @@ get_remote_cups_devices_cb (GObject      *source_object,
   PpNewPrinterDialog        *dialog;
   PpNewPrinterDialogPrivate *priv;
   PpHost                    *host = (PpHost *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
   PpDevicesList             *result;
 
   result = pp_host_get_remote_cups_devices_finish (host, res, &error);
@@ -1296,8 +1287,6 @@ get_remote_cups_devices_cb (GObject      *source_object,
 
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1310,7 +1299,7 @@ get_samba_host_devices_cb (GObject      *source_object,
   PpNewPrinterDialog        *dialog;
   PpDevicesList             *result;
   PpSamba                   *samba = (PpSamba *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
 
   result = pp_samba_get_devices_finish (samba, res, &error);
   g_object_unref (source_object);
@@ -1344,8 +1333,6 @@ get_samba_host_devices_cb (GObject      *source_object,
 
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1358,7 +1345,7 @@ get_samba_devices_cb (GObject      *source_object,
   PpNewPrinterDialog        *dialog;
   PpDevicesList             *result;
   PpSamba                   *samba = (PpSamba *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
 
   result = pp_samba_get_devices_finish (samba, res, &error);
   g_object_unref (source_object);
@@ -1390,8 +1377,6 @@ get_samba_devices_cb (GObject      *source_object,
 
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1403,7 +1388,7 @@ get_jetdirect_devices_cb (GObject      *source_object,
   PpNewPrinterDialog        *dialog;
   PpNewPrinterDialogPrivate *priv;
   PpHost                    *host = (PpHost *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
   PpDevicesList             *result;
 
   result = pp_host_get_jetdirect_devices_finish (host, res, &error);
@@ -1437,8 +1422,6 @@ get_jetdirect_devices_cb (GObject      *source_object,
 
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1450,7 +1433,7 @@ get_lpd_devices_cb (GObject      *source_object,
   PpNewPrinterDialog        *dialog;
   PpNewPrinterDialogPrivate *priv;
   PpHost                    *host = (PpHost *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
   PpDevicesList             *result;
 
   result = pp_host_get_lpd_devices_finish (host, res, &error);
@@ -1484,8 +1467,6 @@ get_lpd_devices_cb (GObject      *source_object,
 
           update_dialog_state (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1950,7 +1931,7 @@ cups_get_dests_cb (GObject      *source_object,
   PpNewPrinterDialogPrivate *priv;
   PpCupsDests               *dests;
   PpCups                    *cups = (PpCups *) source_object;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
 
   dests = pp_cups_get_dests_finish (cups, res, &error);
   g_object_unref (source_object);
@@ -1976,8 +1957,6 @@ cups_get_dests_cb (GObject      *source_object,
 
           get_cups_devices (dialog);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -2134,7 +2113,7 @@ printer_add_async_cb (GObject      *source_object,
   GtkResponseType            response_id = GTK_RESPONSE_OK;
   PpNewPrinter              *new_printer = (PpNewPrinter *) source_object;
   gboolean                   success;
-  GError                    *error = NULL;
+  g_autoptr(GError)          error = NULL;
 
   success = pp_new_printer_add_finish (new_printer, res, &error);
   g_object_unref (source_object);
@@ -2158,8 +2137,6 @@ printer_add_async_cb (GObject      *source_object,
 
           emit_response (dialog, response_id);
         }
-
-      g_error_free (error);
     }
 }
 
diff --git a/panels/printers/pp-new-printer.c b/panels/printers/pp-new-printer.c
index e1e480817..0c2177743 100644
--- a/panels/printers/pp-new-printer.c
+++ b/panels/printers/pp-new-printer.c
@@ -411,7 +411,7 @@ printer_add_real_async_dbus_cb (GObject      *source_object,
   PpNewPrinter        *printer = (PpNewPrinter *) user_data;
   PpNewPrinterPrivate *priv = printer->priv;
   GVariant            *output;
-  GError              *error = NULL;
+  g_autoptr(GError)    error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -445,9 +445,6 @@ printer_add_real_async_dbus_cb (GObject      *source_object,
                             printer_add_real_async_cb,
                             printer);
     }
-
-  if (error)
-      g_error_free (error);
 }
 
 static void
@@ -455,7 +452,7 @@ printer_add_real_async (PpNewPrinter *printer)
 {
   PpNewPrinterPrivate *priv = printer->priv;
   GDBusConnection     *bus;
-  GError              *error = NULL;
+  g_autoptr(GError)    error = NULL;
 
   if (!priv->ppd_name && !priv->ppd_file_name)
     {
@@ -467,7 +464,6 @@ printer_add_real_async (PpNewPrinter *printer)
   if (!bus)
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       _pp_new_printer_add_async_cb (FALSE, printer);
       return;
     }
@@ -560,7 +556,7 @@ printer_add_async_scb3 (GObject      *source_object,
   PpNewPrinterPrivate *priv = printer->priv;
   GVariant            *output;
   PPDName             *ppd_item = NULL;
-  GError              *error = NULL;
+  g_autoptr(GError)    error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -592,11 +588,6 @@ printer_add_async_scb3 (GObject      *source_object,
       _pp_new_printer_add_async_cb (FALSE, printer);
     }
 
-  if (error)
-    {
-      g_error_free (error);
-    }
-
   if (ppd_item)
     {
       g_free (ppd_item->ppd_name);
@@ -612,7 +603,7 @@ install_printer_drivers_cb (GObject      *source_object,
   PpNewPrinterPrivate *priv;
   PpNewPrinter        *printer;
   GVariant            *output;
-  GError              *error = NULL;
+  g_autoptr(GError)    error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -634,14 +625,14 @@ install_printer_drivers_cb (GObject      *source_object,
       error->domain != G_IO_ERROR ||
       error->code != G_IO_ERROR_CANCELLED)
     {
-      GDBusConnection *bus;
-      GError          *error = NULL;
+      GDBusConnection  *bus;
+      g_autoptr(GError) bus_error = NULL;
 
       printer = (PpNewPrinter *) user_data;
       priv = printer->priv;
 
       /* Try whether CUPS has a driver for the new printer */
-      bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &error);
+      bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &bus_error);
       if (bus)
         {
           g_dbus_connection_call (bus,
@@ -662,14 +653,10 @@ install_printer_drivers_cb (GObject      *source_object,
         }
       else
         {
-          g_warning ("Failed to get system bus: %s", error->message);
-          g_error_free (error);
+          g_warning ("Failed to get system bus: %s", bus_error->message);
           _pp_new_printer_add_async_cb (FALSE, printer);
         }
     }
-
-  if (error)
-    g_error_free (error);
 }
 
 static void
@@ -684,7 +671,7 @@ printer_add_async_scb (GObject      *source_object,
   GVariant            *output;
   gboolean             cancelled = FALSE;
   PPDName             *ppd_item = NULL;
-  GError              *error = NULL;
+  g_autoptr(GError)    error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -702,15 +689,15 @@ printer_add_async_scb (GObject      *source_object,
 
       if (!cancelled)
         g_warning ("%s", error->message);
-
-      g_clear_error (&error);
     }
 
   if (!cancelled)
     {
       if (ppd_item == NULL || ppd_item->ppd_match_level < PPD_EXACT_MATCH)
         {
-          bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &error);
+	  g_autoptr(GError) bus_error = NULL;
+
+          bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &bus_error);
           if (bus)
             {
               g_variant_builder_init (&array_builder, G_VARIANT_TYPE ("as"));
@@ -734,8 +721,7 @@ printer_add_async_scb (GObject      *source_object,
             }
           else
             {
-              g_warning ("Failed to get session bus: %s", error->message);
-              g_error_free (error);
+              g_warning ("Failed to get session bus: %s", bus_error->message);
               _pp_new_printer_add_async_cb (FALSE, printer);
             }
         }
@@ -843,9 +829,9 @@ printer_set_accepting_jobs_cb (GObject      *source_object,
                                GAsyncResult *res,
                                gpointer      user_data)
 {
-  GVariant *output;
-  PCData   *data = (PCData *) user_data;
-  GError   *error = NULL;
+  GVariant         *output;
+  PCData           *data = (PCData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -861,7 +847,6 @@ printer_set_accepting_jobs_cb (GObject      *source_object,
       if (error->domain != G_IO_ERROR ||
           error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   data->set_accept_jobs_finished = TRUE;
@@ -873,9 +858,9 @@ printer_set_enabled_cb (GObject      *source_object,
                         GAsyncResult *res,
                         gpointer      user_data)
 {
-  GVariant *output;
-  PCData   *data = (PCData *) user_data;
-  GError   *error = NULL;
+  GVariant         *output;
+  PCData           *data = (PCData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -891,7 +876,6 @@ printer_set_enabled_cb (GObject      *source_object,
       if (error->domain != G_IO_ERROR ||
           error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   data->set_enabled_finished = TRUE;
@@ -945,9 +929,9 @@ install_package_names_cb (GObject      *source_object,
                           GAsyncResult *res,
                           gpointer      user_data)
 {
-  GVariant *output;
-  IMEData  *data = (IMEData *) user_data;
-  GError   *error = NULL;
+  GVariant         *output;
+  IMEData          *data = (IMEData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -963,7 +947,6 @@ install_package_names_cb (GObject      *source_object,
       if (error->domain != G_IO_ERROR ||
           error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   install_missing_executables_cb (data);
@@ -975,10 +958,10 @@ search_files_cb (GObject      *source_object,
                  GAsyncResult *res,
                  gpointer      user_data)
 {
-  GVariant *output;
-  IMEData  *data = (IMEData *) user_data;
-  GError   *error = NULL;
-  GList    *item;
+  GVariant         *output;
+  IMEData          *data = (IMEData *) user_data;
+  g_autoptr(GError) error = NULL;
+  GList            *item;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -1002,7 +985,6 @@ search_files_cb (GObject      *source_object,
       if (error->domain != G_IO_ERROR ||
           error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   if (data->executables)
@@ -1075,11 +1057,11 @@ get_missing_executables_cb (GObject      *source_object,
                             GAsyncResult *res,
                             gpointer      user_data)
 {
-  GVariant *output;
-  IMEData  *data = (IMEData *) user_data;
-  GError   *error = NULL;
-  GList    *executables = NULL;
-  GList    *item;
+  GVariant         *output;
+  IMEData          *data = (IMEData *) user_data;
+  g_autoptr(GError) error = NULL;
+  GList            *executables = NULL;
+  GList            *item;
 
   if (data->ppd_file_name)
     {
@@ -1122,14 +1104,12 @@ get_missing_executables_cb (GObject      *source_object,
     {
       g_warning ("Install system-config-printer which provides \
 DBus method \"MissingExecutables\" to find missing executables and filters.");
-      g_error_free (error);
     }
   else
     {
       if (error->domain != G_IO_ERROR ||
           error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   executables = g_list_sort (executables, (GCompareFunc) g_strcmp0);
@@ -1169,9 +1149,9 @@ static void
 printer_get_ppd_cb (const gchar *ppd_filename,
                     gpointer     user_data)
 {
-  GDBusConnection *bus;
-  IMEData         *data = (IMEData *) user_data;
-  GError          *error = NULL;
+  GDBusConnection  *bus;
+  IMEData          *data = (IMEData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   data->ppd_file_name = g_strdup (ppd_filename);
   if (data->ppd_file_name)
@@ -1180,7 +1160,6 @@ printer_get_ppd_cb (const gchar *ppd_filename,
       if (!bus)
         {
           g_warning ("%s", error->message);
-          g_error_free (error);
         }
       else
         {
@@ -1209,7 +1188,7 @@ pp_maintenance_command_execute_cb (GObject      *source_object,
                                    gpointer      user_data)
 {
   PpMaintenanceCommand *command = (PpMaintenanceCommand *) source_object;
-  GError               *error = NULL;
+  g_autoptr(GError)     error = NULL;
   PCData               *data;
   gboolean              result;
 
@@ -1235,8 +1214,6 @@ pp_maintenance_command_execute_cb (GObject      *source_object,
           data->autoconfigure_finished = TRUE;
           printer_configure_async_finish (data);
         }
-
-      g_error_free (error);
     }
 }
 
@@ -1248,7 +1225,7 @@ printer_configure_async (PpNewPrinter *new_printer)
   PCData               *data;
   IMEData              *ime_data;
   gchar               **values;
-  GError               *error = NULL;
+  g_autoptr(GError)     error = NULL;
 
   data = g_new0 (PCData, 1);
   data->new_printer = new_printer;
@@ -1298,7 +1275,6 @@ printer_configure_async (PpNewPrinter *new_printer)
       else
         {
           g_warning ("Failed to get system bus: %s", error->message);
-          g_error_free (error);
           data->set_accept_jobs_finished = TRUE;
           data->set_enabled_finished = TRUE;
         }
@@ -1365,8 +1341,8 @@ _pp_new_printer_add_async (GSimpleAsyncResult *res,
     }
   else if (priv->device_id)
     {
-      GDBusConnection *bus;
-      GError          *error = NULL;
+      GDBusConnection  *bus;
+      g_autoptr(GError) error = NULL;
 
       /* Try whether CUPS has a driver for the new printer */
       bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, &error);
@@ -1391,7 +1367,6 @@ _pp_new_printer_add_async (GSimpleAsyncResult *res,
       else
         {
           g_warning ("Failed to get system bus: %s", error->message);
-          g_error_free (error);
           _pp_new_printer_add_async_cb (FALSE, printer);
         }
     }
diff --git a/panels/printers/pp-options-dialog.c b/panels/printers/pp-options-dialog.c
index 366808f80..f789dd986 100644
--- a/panels/printers/pp-options-dialog.c
+++ b/panels/printers/pp-options-dialog.c
@@ -933,11 +933,11 @@ pp_options_dialog_new (GtkWindow            *parent,
                        gchar                *printer_name,
                        gboolean              sensitive)
 {
-  PpOptionsDialog *dialog;
-  GtkWidget       *test_page_button;
-  GError          *error = NULL;
-  gchar           *objects[] = { "options-dialog", NULL };
-  guint            builder_result;
+  PpOptionsDialog  *dialog;
+  GtkWidget        *test_page_button;
+  g_autoptr(GError) error = NULL;
+  gchar            *objects[] = { "options-dialog", NULL };
+  guint             builder_result;
 
   dialog = g_new0 (PpOptionsDialog, 1);
 
@@ -951,7 +951,6 @@ pp_options_dialog_new (GtkWindow            *parent,
   if (builder_result == 0)
     {
       g_warning ("Could not load ui: %s", error->message);
-      g_error_free (error);
       return NULL;
     }
 
diff --git a/panels/printers/pp-ppd-selection-dialog.c b/panels/printers/pp-ppd-selection-dialog.c
index 6851fc65a..62f9ae64c 100644
--- a/panels/printers/pp-ppd-selection-dialog.c
+++ b/panels/printers/pp-ppd-selection-dialog.c
@@ -333,7 +333,7 @@ pp_ppd_selection_dialog_new (GtkWindow            *parent,
 {
   PpPPDSelectionDialog *dialog;
   GtkWidget            *widget;
-  GError               *error = NULL;
+  g_autoptr(GError)     error = NULL;
   gchar                *objects[] = { "ppd-selection-dialog", NULL };
   guint                 builder_result;
 
@@ -349,7 +349,6 @@ pp_ppd_selection_dialog_new (GtkWindow            *parent,
   if (builder_result == 0)
     {
       g_warning ("Could not load ui: %s", error->message);
-      g_error_free (error);
       return NULL;
     }
 
diff --git a/panels/printers/pp-printer-entry.c b/panels/printers/pp-printer-entry.c
index 8907ca9d6..c4360aa92 100644
--- a/panels/printers/pp-printer-entry.c
+++ b/panels/printers/pp-printer-entry.c
@@ -507,13 +507,12 @@ check_clean_heads_maintenance_command_cb (GObject      *source_object,
 {
   PpMaintenanceCommand *command = (PpMaintenanceCommand *) source_object;
   gboolean              is_supported = FALSE;
-  GError               *error = NULL;
+  g_autoptr(GError)     error = NULL;
 
   is_supported = pp_maintenance_command_is_supported_finish (command, res, &error);
   if (error != NULL)
     {
       g_debug ("Could not check 'Clean' maintenance command: %s", error->message);
-      g_error_free (error);
       goto out;
     }
 
@@ -549,12 +548,11 @@ clean_heads_maintenance_command_cb (GObject      *source_object,
 {
   PpPrinterEntry       *self = PP_PRINTER_ENTRY (user_data);
   PpMaintenanceCommand *command = (PpMaintenanceCommand *) source_object;
-  GError               *error = NULL;
+  g_autoptr(GError)     error = NULL;
 
   if (!pp_maintenance_command_execute_finish (command, res, &error))
     {
       g_warning ("Error cleaning print heads for %s: %s", self->printer_name, error->message);
-      g_error_free (error);
     }
   g_object_unref (source_object);
 }
@@ -585,12 +583,12 @@ get_jobs_cb (GObject      *source_object,
              GAsyncResult *result,
              gpointer      user_data)
 {
-  PpPrinterEntry *self;
-  PpPrinter      *printer = PP_PRINTER (source_object);
-  GError         *error = NULL;
-  GList          *jobs;
-  gchar          *button_label;
-  gint            num_jobs;
+  PpPrinterEntry   *self;
+  PpPrinter        *printer = PP_PRINTER (source_object);
+  g_autoptr(GError) error = NULL;
+  GList            *jobs;
+  gchar            *button_label;
+  gint              num_jobs;
 
   jobs = pp_printer_get_jobs_finish (printer, result, &error);
   num_jobs = g_list_length (jobs);
@@ -605,7 +603,6 @@ get_jobs_cb (GObject      *source_object,
           g_warning ("Could not get jobs: %s", error->message);
         }
 
-      g_error_free (error);
       return;
     }
 
diff --git a/panels/printers/pp-printer.c b/panels/printers/pp-printer.c
index 87be522db..e85ad6a5c 100644
--- a/panels/printers/pp-printer.c
+++ b/panels/printers/pp-printer.c
@@ -168,12 +168,12 @@ printer_rename_dbus_cb (GObject      *source_object,
                         GAsyncResult *res,
                         gpointer      user_data)
 {
-  PpPrinter *printer;
-  GVariant  *output;
-  gboolean   result = FALSE;
-  GError    *error = NULL;
-  GTask     *task = user_data;
-  gchar     *old_printer_name;
+  PpPrinter        *printer;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
+  GTask            *task = user_data;
+  gchar            *old_printer_name;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -210,7 +210,6 @@ printer_rename_dbus_cb (GObject      *source_object,
            error->code == G_DBUS_ERROR_UNKNOWN_METHOD))
         {
           g_warning ("Update cups-pk-helper to at least 0.2.6 please to be able to use PrinterRename method.");
-          g_error_free (error);
 
           g_task_run_in_thread (task, printer_rename_thread);
         }
@@ -226,10 +225,10 @@ get_bus_cb (GObject      *source_object,
             GAsyncResult *res,
             gpointer      user_data)
 {
-  GDBusConnection *bus;
-  GError          *error = NULL;
-  GTask           *task = user_data;
-  gchar           *printer_name;
+  GDBusConnection  *bus;
+  g_autoptr(GError) error = NULL;
+  GTask            *task = user_data;
+  gchar            *printer_name;
 
   bus = g_bus_get_finish (res, &error);
   if (bus != NULL)
@@ -257,7 +256,6 @@ get_bus_cb (GObject      *source_object,
   else
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       g_task_return_boolean (task, FALSE);
     }
 }
@@ -447,11 +445,11 @@ pp_printer_delete_dbus_cb (GObject      *source_object,
                            GAsyncResult *res,
                            gpointer      user_data)
 {
-  GVariant  *output;
-  gboolean   result = FALSE;
-  GError    *error = NULL;
-  GTask     *task = user_data;
-  gchar     *printer_name;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
+  GTask            *task = user_data;
+  gchar            *printer_name;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -478,7 +476,6 @@ pp_printer_delete_dbus_cb (GObject      *source_object,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
 
       g_task_return_boolean (task, FALSE);
     }
@@ -489,10 +486,10 @@ pp_printer_delete_cb (GObject      *source_object,
                       GAsyncResult *res,
                       gpointer      user_data)
 {
-  GDBusConnection *bus;
-  GError          *error = NULL;
-  GTask           *task = user_data;
-  gchar           *printer_name;
+  GDBusConnection  *bus;
+  g_autoptr(GError) error = NULL;
+  GTask            *task = user_data;
+  gchar            *printer_name;
 
   bus = g_bus_get_finish (res, &error);
   if (bus != NULL)
@@ -519,7 +516,6 @@ pp_printer_delete_cb (GObject      *source_object,
   else
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       g_task_return_boolean (task, FALSE);
     }
 }
diff --git a/panels/printers/pp-utils.c b/panels/printers/pp-utils.c
index 68eaa9871..f677a38c9 100644
--- a/panels/printers/pp-utils.c
+++ b/panels/printers/pp-utils.c
@@ -273,7 +273,7 @@ printer_rename (const gchar *old_name,
   gboolean          printer_paused = FALSE;
   gboolean          default_printer = FALSE;
   gboolean          printer_shared = FALSE;
-  GError           *error = NULL;
+  g_autoptr(GError) error = NULL;
   http_t           *http;
   gchar            *ppd_link;
   gchar            *ppd_filename = NULL;
@@ -446,7 +446,6 @@ printer_rename (const gchar *old_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
    }
   else
     {
@@ -458,7 +457,8 @@ printer_rename (const gchar *old_name,
         }
       else
         {
-          GVariant *output;
+          GVariant         *output;
+          g_autoptr(GError) add_error = NULL;
 
           output = g_dbus_connection_call_sync (bus,
                                                 MECHANISM_BUS,
@@ -475,7 +475,7 @@ printer_rename (const gchar *old_name,
                                                 G_DBUS_CALL_FLAGS_NONE,
                                                 -1,
                                                 NULL,
-                                                &error);
+                                                &add_error);
           g_object_unref (bus);
 
           if (output)
@@ -490,8 +490,7 @@ printer_rename (const gchar *old_name,
             }
           else
             {
-              g_warning ("%s", error->message);
-              g_error_free (error);
+              g_warning ("%s", add_error->message);
             }
         }
     }
@@ -542,10 +541,10 @@ gboolean
 printer_set_location (const gchar *printer_name,
                       const gchar *location)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name || !location)
     return TRUE;
@@ -554,7 +553,6 @@ printer_set_location (const gchar *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -586,7 +584,6 @@ printer_set_location (const gchar *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -597,10 +594,10 @@ printer_set_accepting_jobs (const gchar *printer_name,
                             gboolean     accepting_jobs,
                             const gchar *reason)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name)
     return TRUE;
@@ -609,7 +606,6 @@ printer_set_accepting_jobs (const gchar *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -643,7 +639,6 @@ printer_set_accepting_jobs (const gchar *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -653,10 +648,10 @@ gboolean
 printer_set_enabled (const gchar *printer_name,
                      gboolean     enabled)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name)
     return TRUE;
@@ -665,7 +660,6 @@ printer_set_enabled (const gchar *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -697,7 +691,6 @@ printer_set_enabled (const gchar *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -706,10 +699,10 @@ printer_set_enabled (const gchar *printer_name,
 gboolean
 printer_delete (const gchar *printer_name)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name)
     return TRUE;
@@ -718,7 +711,6 @@ printer_delete (const gchar *printer_name)
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -750,7 +742,6 @@ printer_delete (const gchar *printer_name)
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -759,11 +750,11 @@ printer_delete (const gchar *printer_name)
 gboolean
 printer_set_default (const gchar *printer_name)
 {
-  GDBusConnection *bus;
-  const char *cups_server;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  const char       *cups_server;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name)
     return TRUE;
@@ -783,7 +774,6 @@ printer_set_default (const gchar *printer_name)
       if (!bus)
         {
           g_warning ("Failed to get system bus: %s", error->message);
-          g_error_free (error);
         }
       else
         {
@@ -815,7 +805,6 @@ printer_set_default (const gchar *printer_name)
           else
             {
               g_warning ("%s", error->message);
-              g_error_free (error);
             }
         }
     }
@@ -834,10 +823,10 @@ gboolean
 printer_set_shared (const gchar *printer_name,
                     gboolean     shared)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name)
     return TRUE;
@@ -846,7 +835,6 @@ printer_set_shared (const gchar *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -878,7 +866,6 @@ printer_set_shared (const gchar *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -889,10 +876,10 @@ printer_set_job_sheets (const gchar *printer_name,
                         const gchar *start_sheet,
                         const gchar *end_sheet)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  GError     *error = NULL;
-  gboolean    result = FALSE;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  g_autoptr(GError) error = NULL;
+  gboolean          result = FALSE;
 
   if (!printer_name || !start_sheet || !end_sheet)
     return TRUE;
@@ -901,7 +888,6 @@ printer_set_job_sheets (const gchar *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -933,7 +919,6 @@ printer_set_job_sheets (const gchar *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -944,10 +929,10 @@ printer_set_policy (const gchar *printer_name,
                     const gchar *policy,
                     gboolean     error_policy)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean   result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name || !policy)
     return TRUE;
@@ -956,7 +941,6 @@ printer_set_policy (const gchar *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -1001,7 +985,6 @@ printer_set_policy (const gchar *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -1012,12 +995,12 @@ printer_set_users (const gchar  *printer_name,
                    gchar       **users,
                    gboolean      allowed)
 {
-  GDBusConnection *bus;
-  GVariantBuilder array_builder;
-  gint        i;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariantBuilder   array_builder;
+  gint              i;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!printer_name || !users)
     return TRUE;
@@ -1026,7 +1009,6 @@ printer_set_users (const gchar  *printer_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -1075,7 +1057,6 @@ printer_set_users (const gchar  *printer_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -1085,10 +1066,10 @@ gboolean
 class_add_printer (const gchar *class_name,
                    const gchar *printer_name)
 {
-  GDBusConnection *bus;
-  GVariant   *output;
-  gboolean    result = FALSE;
-  GError     *error = NULL;
+  GDBusConnection  *bus;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  g_autoptr(GError) error = NULL;
 
   if (!class_name || !printer_name)
     return TRUE;
@@ -1097,7 +1078,6 @@ class_add_printer (const gchar *class_name,
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      return TRUE;
    }
 
@@ -1129,7 +1109,6 @@ class_add_printer (const gchar *class_name,
   else
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   return result;
@@ -1411,9 +1390,9 @@ get_ipp_attributes_async (const gchar  *printer_name,
                           GIACallback   callback,
                           gpointer      user_data)
 {
-  GIAData *data;
-  GThread *thread;
-  GError  *error = NULL;
+  GIAData          *data;
+  GThread          *thread;
+  g_autoptr(GError) error = NULL;
 
   data = g_new0 (GIAData, 1);
   data->printer_name = g_strdup (printer_name);
@@ -1432,7 +1411,6 @@ get_ipp_attributes_async (const gchar  *printer_name,
       g_warning ("%s", error->message);
       callback (NULL, user_data);
 
-      g_error_free (error);
       get_ipp_attributes_data_free (data);
     }
   else
@@ -1497,10 +1475,10 @@ printer_set_ppd_async_dbus_cb (GObject      *source_object,
                                GAsyncResult *res,
                                gpointer      user_data)
 {
-  GVariant *output;
-  gboolean  result = FALSE;
-  PSPData  *data = (PSPData *) user_data;
-  GError   *error = NULL;
+  GVariant         *output;
+  gboolean          result = FALSE;
+  PSPData          *data = (PSPData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -1523,7 +1501,6 @@ printer_set_ppd_async_dbus_cb (GObject      *source_object,
     {
       if (error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   /* Don't call callback if cancelled */
@@ -1557,9 +1534,9 @@ printer_set_ppd_async (const gchar  *printer_name,
                        PSPCallback   callback,
                        gpointer      user_data)
 {
-  GDBusConnection *bus;
-  PSPData         *data;
-  GError          *error = NULL;
+  GDBusConnection  *bus;
+  PSPData          *data;
+  g_autoptr(GError) error = NULL;
 
   data = g_new0 (PSPData, 1);
   if (cancellable)
@@ -1578,7 +1555,6 @@ printer_set_ppd_async (const gchar  *printer_name,
   if (!bus)
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       goto out;
     }
 
@@ -1616,10 +1592,10 @@ printer_set_ppd_file_async_scb (GObject      *source_object,
                                 GAsyncResult *res,
                                 gpointer      user_data)
 {
-  GDBusConnection *bus;
-  gboolean         success;
-  PSPData         *data = (PSPData *) user_data;
-  GError          *error = NULL;
+  GDBusConnection  *bus;
+  gboolean          success;
+  PSPData          *data = (PSPData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   success = g_file_copy_finish (G_FILE (source_object),
                                 res,
@@ -1629,7 +1605,6 @@ printer_set_ppd_file_async_scb (GObject      *source_object,
   if (!success)
     {
       g_warning ("%s", error->message);
-      g_error_free (error);
       goto out;
     }
 
@@ -1637,7 +1612,6 @@ printer_set_ppd_file_async_scb (GObject      *source_object,
   if (!bus)
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       goto out;
     }
 
@@ -1828,9 +1802,9 @@ get_ppds_attribute_async (gchar       **ppds_names,
                           GPACallback   callback,
                           gpointer      user_data)
 {
-  GPAData *data;
-  GThread *thread;
-  GError  *error = NULL;
+  GPAData          *data;
+  GThread          *thread;
+  g_autoptr(GError) error = NULL;
 
   if (!ppds_names || !attribute_name)
     {
@@ -1855,7 +1829,6 @@ get_ppds_attribute_async (gchar       **ppds_names,
       g_warning ("%s", error->message);
       callback (NULL, user_data);
 
-      g_error_free (error);
       get_ppds_attribute_data_free (data);
     }
   else
@@ -1939,14 +1912,14 @@ get_ppd_names_async_dbus_scb (GObject      *source_object,
                               GAsyncResult *res,
                               gpointer      user_data)
 {
-  GVariant  *output;
-  PPDName   *ppd_item;
-  PPDName  **result = NULL;
-  GPNData   *data = (GPNData *) user_data;
-  GError    *error = NULL;
-  GList     *driver_list = NULL;
-  GList     *iter;
-  gint       i, j, n = 0;
+  GVariant         *output;
+  PPDName          *ppd_item;
+  PPDName         **result = NULL;
+  GPNData          *data = (GPNData *) user_data;
+  g_autoptr(GError) error = NULL;
+  GList            *driver_list = NULL;
+  GList            *iter;
+  gint              i, j, n = 0;
   static const char * const match_levels[] = {
              "exact-cmd",
              "exact",
@@ -2022,7 +1995,6 @@ get_ppd_names_async_dbus_scb (GObject      *source_object,
     {
       if (error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   if (n > 0)
@@ -2073,9 +2045,9 @@ get_device_attributes_cb (gchar    *device_id,
                           gchar    *device_uri,
                           gpointer  user_data)
 {
-  GDBusConnection *bus;
-  GError          *error = NULL;
-  GPNData         *data = (GPNData *) user_data;
+  GDBusConnection  *bus;
+  g_autoptr(GError) error = NULL;
+  GPNData          *data = (GPNData *) user_data;
 
   if (g_cancellable_is_cancelled (data->cancellable))
     goto out;
@@ -2087,7 +2059,6 @@ get_device_attributes_cb (gchar    *device_id,
   if (!bus)
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       goto out;
     }
 
@@ -2181,12 +2152,12 @@ get_device_attributes_async_dbus_cb (GObject      *source_object,
                                      gpointer      user_data)
 
 {
-  GVariant *output;
-  GDAData  *data = (GDAData *) user_data;
-  GError   *error = NULL;
-  GList    *tmp;
-  gchar    *device_id = NULL;
-  gchar    *device_make_and_model = NULL;
+  GVariant         *output;
+  GDAData          *data = (GDAData *) user_data;
+  g_autoptr(GError) error = NULL;
+  GList            *tmp;
+  gchar            *device_id = NULL;
+  gchar            *device_make_and_model = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -2295,7 +2266,6 @@ get_device_attributes_async_dbus_cb (GObject      *source_object,
     {
       if (error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   if (!device_id || !device_make_and_model)
@@ -2380,12 +2350,12 @@ static void
 get_device_attributes_async_scb (GHashTable *result,
                                  gpointer    user_data)
 {
-  GDBusConnection *bus;
-  GVariantBuilder  include_scheme_builder;
-  IPPAttribute    *attr;
-  GDAData         *data = (GDAData *) user_data;
-  GError          *error = NULL;
-  GList           *tmp;
+  GDBusConnection  *bus;
+  GVariantBuilder   include_scheme_builder;
+  IPPAttribute     *attr;
+  GDAData          *data = (GDAData *) user_data;
+  g_autoptr(GError) error = NULL;
+  GList            *tmp;
 
   if (result)
     {
@@ -2406,7 +2376,6 @@ get_device_attributes_async_scb (GHashTable *result,
   if (!bus)
     {
       g_warning ("Failed to get system bus: %s", error->message);
-      g_error_free (error);
       goto out;
     }
 
@@ -2890,9 +2859,9 @@ get_all_ppds_async (GCancellable *cancellable,
                     GAPCallback   callback,
                     gpointer      user_data)
 {
-  GAPData *data;
-  GThread *thread;
-  GError  *error = NULL;
+  GAPData          *data;
+  GThread          *thread;
+  g_autoptr(GError) error = NULL;
 
   data = g_new0 (GAPData, 1);
   if (cancellable)
@@ -2911,7 +2880,6 @@ get_all_ppds_async (GCancellable *cancellable,
       g_warning ("%s", error->message);
       callback (NULL, user_data);
 
-      g_error_free (error);
       get_all_ppds_data_free (data);
     }
   else
@@ -3098,9 +3066,9 @@ printer_get_ppd_async (const gchar *printer_name,
                        PGPCallback  callback,
                        gpointer     user_data)
 {
-  PGPData *data;
-  GThread *thread;
-  GError  *error = NULL;
+  PGPData          *data;
+  GThread          *thread;
+  g_autoptr(GError) error = NULL;
 
   data = g_new0 (PGPData, 1);
   data->printer_name = g_strdup (printer_name);
@@ -3120,7 +3088,6 @@ printer_get_ppd_async (const gchar *printer_name,
       g_warning ("%s", error->message);
       callback (NULL, user_data);
 
-      g_error_free (error);
       printer_get_ppd_data_free (data);
     }
   else
@@ -3201,9 +3168,9 @@ get_named_dest_async (const gchar *printer_name,
                       GNDCallback  callback,
                       gpointer     user_data)
 {
-  GNDData *data;
-  GThread *thread;
-  GError  *error = NULL;
+  GNDData          *data;
+  GThread          *thread;
+  g_autoptr(GError) error = NULL;
 
   data = g_new0 (GNDData, 1);
   data->printer_name = g_strdup (printer_name);
@@ -3221,7 +3188,6 @@ get_named_dest_async (const gchar *printer_name,
       g_warning ("%s", error->message);
       callback (NULL, user_data);
 
-      g_error_free (error);
       get_named_dest_data_free (data);
     }
   else
@@ -3242,10 +3208,10 @@ printer_add_option_async_dbus_cb (GObject      *source_object,
                                   GAsyncResult *res,
                                   gpointer      user_data)
 {
-  GVariant *output;
-  gboolean  success = FALSE;
-  PAOData  *data = (PAOData *) user_data;
-  GError   *error = NULL;
+  GVariant         *output;
+  gboolean          success = FALSE;
+  PAOData          *data = (PAOData *) user_data;
+  g_autoptr(GError) error = NULL;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -3268,7 +3234,6 @@ printer_add_option_async_dbus_cb (GObject      *source_object,
     {
       if (error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
     }
 
   if (!g_cancellable_is_cancelled (data->cancellable))
@@ -3288,17 +3253,16 @@ printer_add_option_async (const gchar   *printer_name,
                           PAOCallback    callback,
                           gpointer       user_data)
 {
-  GVariantBuilder  array_builder;
-  GDBusConnection *bus;
-  PAOData         *data;
-  GError          *error = NULL;
-  gint             i;
+  GVariantBuilder   array_builder;
+  GDBusConnection  *bus;
+  PAOData          *data;
+  g_autoptr(GError) error = NULL;
+  gint              i;
 
   bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &error);
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      callback (FALSE, user_data);
      return;
    }
@@ -3367,12 +3331,12 @@ get_cups_devices_async_dbus_cb (GObject      *source_object,
                                 gpointer      user_data)
 
 {
-  PpPrintDevice **devices = NULL;
-  GVariant       *output;
-  GCDData        *data = (GCDData *) user_data;
-  GError         *error = NULL;
-  GList          *result = NULL;
-  gint            num_of_devices = 0;
+  PpPrintDevice   **devices = NULL;
+  GVariant         *output;
+  GCDData          *data = (GCDData *) user_data;
+  g_autoptr(GError) error = NULL;
+  GList            *result = NULL;
+  gint              num_of_devices = 0;
 
   output = g_dbus_connection_call_finish (G_DBUS_CONNECTION (source_object),
                                           res,
@@ -3476,7 +3440,6 @@ get_cups_devices_async_dbus_cb (GObject      *source_object,
       if (error->domain != G_IO_ERROR ||
           error->code != G_IO_ERROR_CANCELLED)
         g_warning ("%s", error->message);
-      g_error_free (error);
 
       data->callback (result,
                       TRUE,
@@ -3576,17 +3539,16 @@ get_cups_devices_async (GCancellable *cancellable,
                         GCDCallback   callback,
                         gpointer      user_data)
 {
-  GDBusConnection *bus;
-  GVariantBuilder  include_scheme_builder;
-  GCDData         *data;
-  GError          *error = NULL;
-  gchar           *backend_name;
+  GDBusConnection  *bus;
+  GVariantBuilder   include_scheme_builder;
+  GCDData          *data;
+  g_autoptr(GError) error = NULL;
+  gchar            *backend_name;
 
   bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &error);
   if (!bus)
    {
      g_warning ("Failed to get system bus: %s", error->message);
-     g_error_free (error);
      callback (NULL, TRUE, FALSE, user_data);
      return;
    }