[gimp] libgimp: don't use G_IS_FILE() and g_file_get_path() on a NULL GFile

[Michael Natterer <mitch src gnome org>]

commit 42e8a344ab486b2e71ca22401dc0023600c46497
Author: Michael Natterer <mitch gimp org>
Date:   Mon Aug 12 19:09:08 2019 +0200

    libgimp: don't use G_IS_FILE() and g_file_get_path() on a NULL GFile
    
    when registering the plug-in's translation domain. A NULL path is
    allowed and used by script-fu.

 libgimp/gimpplugin-private.c | 5 ++++-
 libgimp/gimpplugin.c         | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/libgimp/gimpplugin-private.c b/libgimp/gimpplugin-private.c
index d6b3d2d55b..3366831bf5 100644
--- a/libgimp/gimpplugin-private.c
+++ b/libgimp/gimpplugin-private.c
@@ -199,7 +199,10 @@ gimp_plug_in_register (GimpPlugIn *plug_in,
 
   if (plug_in->priv->translation_domain_name)
     {
-      gchar *path = g_file_get_path (plug_in->priv->translation_domain_path);
+      gchar *path = NULL;
+
+      if (plug_in->priv->translation_domain_path)
+        path = g_file_get_path (plug_in->priv->translation_domain_path);
 
       _gimp_plugin_domain_register (plug_in->priv->translation_domain_name,
                                     path);
diff --git a/libgimp/gimpplugin.c b/libgimp/gimpplugin.c
index 5f0e4d84f2..c02be8ebc1 100644
--- a/libgimp/gimpplugin.c
+++ b/libgimp/gimpplugin.c
@@ -226,7 +226,7 @@ gimp_plug_in_get_property (GObject    *object,
  * gimp_plug_in_set_translation_domain:
  * @plug_in:     A #GimpPlugIn.
  * @domain_name: The name of the textdomain (must be unique).
- * @domain_path: The absolute path to the compiled message catalog
+ * @domain_path: (nullable): A #GFile pointing to the compiled message catalog
  *               (may be %NULL).
  *
  * Sets a textdomain for localisation for the @plug_in.
@@ -250,7 +250,7 @@ gimp_plug_in_set_translation_domain (GimpPlugIn  *plug_in,
 {
   g_return_if_fail (GIMP_IS_PLUG_IN (plug_in));
   g_return_if_fail (domain_name != NULL);
-  g_return_if_fail (G_IS_FILE (domain_path));
+  g_return_if_fail (domain_path == NULL || G_IS_FILE (domain_path));
 
   g_free (plug_in->priv->translation_domain_name);
   plug_in->priv->translation_domain_name = g_strdup (domain_name);