object: Try to lookup an object parent prototype from the parent gtype

In some cases we were not able to find the parent prototype by just
looking at the saved gtypes, as they may be static types defined in C.

This was leading to errors when initializing from static functions, so
fix this.

1 files changed, 6 insertions, 0 deletions

diff --git a/gi/object.cpp b/gi/object.cpp
index 3ced434f..c9b00dbe 100644
--- a/gi/object.cpp
+++ b/gi/object.cpp
@@ -2070,6 +2070,12 @@ GIFieldInfo* ObjectPrototype::lookup_cached_field_info(JSContext* cx,
                  "Custom JS class must have parent");
         ObjectPrototype* parent_proto =
             ObjectPrototype::for_gtype(parent_gtype);
+
+        if (!parent_proto) {
+            JS::RootedObject proto(cx, gjs_lookup_object_prototype(cx, parent_gtype));
+            parent_proto = ObjectPrototype::for_js(cx, proto);
+        }
+
         g_assert(parent_proto &&
                  "Custom JS class's parent must have been accessed in JS");
         return parent_proto->lookup_cached_field_info(cx, key);