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, 3 insertions, 2 deletions

diff --git a/source/blender/makesrna/RNA_define.h b/source/blender/makesrna/RNA_define.h
index c49a52ceed7..bc1a8f52b8d 100644
--- a/source/blender/makesrna/RNA_define.h
+++ b/source/blender/makesrna/RNA_define.h
@@ -465,8 +465,6 @@ void RNA_def_property_string_funcs_runtime(PropertyRNA *prop,
                                            StringPropertyLengthFunc lengthfunc,
                                            StringPropertySetFunc setfunc);
 
-void RNA_def_property_enum_py_data(PropertyRNA *prop, void *py_data);
-
 void RNA_def_property_translation_context(PropertyRNA *prop, const char *context);
 
 /* Function */
@@ -507,6 +505,9 @@ void RNA_def_property_duplicate_pointers(StructOrFunctionRNA *cont_, PropertyRNA
 void RNA_def_property_free_pointers(PropertyRNA *prop);
 int RNA_def_property_free_identifier(StructOrFunctionRNA *cont_, const char *identifier);
 
+void RNA_def_property_free_pointers_set_py_data_callback(
+    void (*py_data_clear_fn)(PropertyRNA *prop));
+
 /* utilities */
 const char *RNA_property_typename(PropertyType type);
 #define IS_DNATYPE_FLOAT_COMPAT(_str) (strcmp(_str, "float") == 0 || strcmp(_str, "double") == 0)