Fix T86332: Error using lambda in annotations in Python 3.10

Callbacks used in `bpy.props` didn't hold a references to the functions
they used.

While this has been the case since early 2.5x it didn't cause any
problems as long as the class held a reference.

With Python 3.10 or when using `from __future__ import annotations`,
the annotations are no longer owned by the class once evaluated.

Resolve this by holding a reference in the module, which now supports
traverse & clear callbacks so the objects are visible to Python's
garbage collector.

Also refactor storage of Python data, moving from an array into a struct.

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/python/intern/bpy_props.h b/source/blender/python/intern/bpy_props.h
index 6cebf82d373..d467166f354 100644
--- a/source/blender/python/intern/bpy_props.h
+++ b/source/blender/python/intern/bpy_props.h
@@ -25,6 +25,7 @@ extern "C" {
 #endif
 
 PyObject *BPY_rna_props(void);
+void BPY_rna_props_clear_all(void);
 
 PyObject *BPy_PointerProperty(PyObject *self, PyObject *args, PyObject *kw);
 PyObject *BPy_CollectionProperty(PyObject *self, PyObject *args, PyObject *kw);