[nautilus] mime-actions: null-check app info

[Ernestas Kulik <ernestask src gnome org>]

commit cd78b1c9863a25a5fae0f2f7f98ca6d58681cbd6
Author: Ernestas Kulik <ernestask gnome org>
Date:   Fri Aug 11 19:57:32 2017 +0300

    mime-actions: null-check app info
    
    When deciding on the activation action, the code checks if Nautilus
    is the default handler for archives. There are cases when the returned
    application info is invalid, e.g. for application/octet-stream.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786168

 src/nautilus-mime-actions.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/nautilus-mime-actions.c b/src/nautilus-mime-actions.c
index 28f1da5..18066d6 100644
--- a/src/nautilus-mime-actions.c
+++ b/src/nautilus-mime-actions.c
@@ -710,13 +710,16 @@ get_activation_action (NautilusFile *file)
 {
     ActivationAction action;
     char *activation_uri;
-    gboolean handles_extract;
+    gboolean handles_extract = FALSE;
     g_autoptr (GAppInfo) app_info = NULL;
     const gchar* app_id;
 
     app_info = nautilus_mime_get_default_application_for_file (file);
-    app_id = g_app_info_get_id (app_info);
-    handles_extract = g_strcmp0 (app_id, NAUTILUS_DESKTOP_ID) == 0;
+    if (app_info != NULL)
+    {
+        app_id = g_app_info_get_id (app_info);
+        handles_extract = g_strcmp0 (app_id, NAUTILUS_DESKTOP_ID) == 0;
+    }
     if (handles_extract && nautilus_file_is_archive (file))
     {
         return ACTIVATION_ACTION_EXTRACT;