[gtk/builder-tool-fixes: 2/2] buildertool: Be more robust

[Matthias Clasen <matthiasc src gnome org>]

commit 66d8631c23cbc05d9937b503986d44c5eb1a480b
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Dec 13 15:08:35 2021 -0500

    buildertool: Be more robust
    
    Don't pass a NULL string to gtk_builder_value_from_string.

 tools/gtk-builder-tool-simplify.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/tools/gtk-builder-tool-simplify.c b/tools/gtk-builder-tool-simplify.c
index 635b6332fa..7aadefa160 100644
--- a/tools/gtk-builder-tool-simplify.c
+++ b/tools/gtk-builder-tool-simplify.c
@@ -432,6 +432,9 @@ value_is_default (Element      *element,
   if (g_type_is_a (G_PARAM_SPEC_VALUE_TYPE (pspec), G_TYPE_BOXED))
     return FALSE;
 
+  if (!value_string)
+    return FALSE;
+
   if (!gtk_builder_value_from_string (data->builder, pspec, value_string, &value, &error))
     {
       g_printerr (_("%s:%d: Couldn’t parse value for property '%s': %s\n"), data->input_filename, 
element->line_number, pspec->name, error->message);