[gobject-introspection] girepository: avoids segfault in case of bad gtype

[Philip Chimento <pchimento src gnome org>]

commit c2579c71222c181068b5aaf795aa0f1e8909d89e
Author: Lukas Oberhuber <lukaso gmail com>
Date:   Tue Jan 11 23:01:08 2022 +0000

    girepository: avoids segfault in case of bad gtype
    
    If a <GType invalid> (that's the way it appears in python's debugger) is
    returned, `g_type_name` returns NULL. This
    function therefore returns NULL at this time
    as subsequent calls to `strlen( data->gtype_name)` segfault.

 girepository/girepository.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/girepository/girepository.c b/girepository/girepository.c
index 7d034859..d7f6ceb4 100644
--- a/girepository/girepository.c
+++ b/girepository/girepository.c
@@ -806,12 +806,14 @@ find_by_gtype (GHashTable *table, FindByGTypeData *data, gboolean check_prefix)
  */
 GIBaseInfo *
 g_irepository_find_by_gtype (GIRepository *repository,
-                            GType         gtype)
+                             GType         gtype)
 {
   FindByGTypeData data;
   GIBaseInfo *cached;
   DirEntry *entry;
 
+  g_return_val_if_fail (gtype != G_TYPE_INVALID, NULL);
+
   repository = get_repository (repository);
 
   cached = g_hash_table_lookup (repository->priv->info_by_gtype,