base-bearer: report connection error on failed connection attempts

When a user-requested connection attempt fails, we not only return the
connection error to the user that requested it, we also publish the
specific connection error in DBus for others to check why the failure
happened.

src/mm-base-bearer.c

@@ -242,6 +242,19 @@ connection_monitor_start (MMBaseBearer *self)
 
 /*****************************************************************************/
 
+static void
+bearer_update_connection_error (MMBaseBearer *self,
+                                const GError *connection_error)
+{
+    g_autoptr(GVariant) tuple = NULL;
+
+    if (connection_error)
+        tuple = mm_common_error_to_tuple (connection_error);
+    mm_gdbus_bearer_set_connection_error (MM_GDBUS_BEARER (self), tuple);
+}
+
+/*****************************************************************************/
+
 static void
 bearer_update_interface_stats (MMBaseBearer *self)
 {
@@ -815,9 +828,12 @@ connect_ready (MMBaseBearer *self,
         if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
             /* Will launch disconnection */
             launch_disconnect = TRUE;
-        } else
+        } else {
+            /* Update reported connection error before the status update */
+            bearer_update_connection_error (self, error);
             bearer_update_status (self, MM_BEARER_STATUS_DISCONNECTED);
         }
+    }
     /* Handle cancellations detected after successful connection */
     else if (g_cancellable_is_cancelled (self->priv->connect_cancellable)) {
         mm_obj_dbg (self, "connected, but need to disconnect");
@@ -841,6 +857,8 @@ connect_ready (MMBaseBearer *self,
     }
 
     if (launch_disconnect) {
+        /* Update reported connection error before the status update */
+        bearer_update_connection_error (self, error);
         bearer_update_status (self, MM_BEARER_STATUS_DISCONNECTING);
         MM_BASE_BEARER_GET_CLASS (self)->disconnect (
             self,