[gnome-software] Show a better translated string for an invalid file type

[Richard Hughes <rhughes src gnome org>]

commit 8fcc294d0bec5163412a3093fc026426c6790224
Author: Richard Hughes <richard hughsie com>
Date:   Wed Mar 16 09:20:40 2016 +0000

    Show a better translated string for an invalid file type

 src/gs-shell-details.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/src/gs-shell-details.c b/src/gs-shell-details.c
index 8f09798..d07e014 100644
--- a/src/gs-shell-details.c
+++ b/src/gs-shell-details.c
@@ -1164,6 +1164,17 @@ gs_shell_details_filename_to_app_cb (GObject *source,
                                                              &error));
        if (self->app == NULL) {
                GtkWidget *dialog;
+               const gchar *msg;
+
+               if (g_error_matches (error,
+                                    GS_PLUGIN_LOADER_ERROR,
+                                    GS_PLUGIN_LOADER_ERROR_NO_RESULTS)) {
+                       /* TRANSLATORS: the file format was not recognised by
+                        * any plugin, e.g. if you try installing a .tar.gz */
+                       msg = _("The file is not supported.");
+               } else {
+                       msg = error->message;
+               }
 
                dialog = gtk_message_dialog_new (gs_shell_get_window (self->shell),
                                                 GTK_DIALOG_MODAL |
@@ -1172,7 +1183,7 @@ gs_shell_details_filename_to_app_cb (GObject *source,
                                                 GTK_BUTTONS_CLOSE,
                                                 _("Sorry, this did not work"));
                gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog),
-                                                         "%s", error->message);
+                                                         "%s", msg);
                g_signal_connect (dialog, "response",
                                  G_CALLBACK (gs_shell_details_failed_response_cb), self);
                gs_shell_modal_dialog_present (self->shell, GTK_DIALOG (dialog));