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.

6 files changed, 21 insertions, 20 deletions

diff --git a/source/blender/makesrna/RNA_access.h b/source/blender/makesrna/RNA_access.h
index 4c60ffe4f16..d41220eb22c 100644
--- a/source/blender/makesrna/RNA_access.h
+++ b/source/blender/makesrna/RNA_access.h
@@ -1021,7 +1021,6 @@ int RNA_property_string_default_length(PointerRNA *ptr, PropertyRNA *prop);
 int RNA_property_enum_get(PointerRNA *ptr, PropertyRNA *prop);
 void RNA_property_enum_set(PointerRNA *ptr, PropertyRNA *prop, int value);
 int RNA_property_enum_get_default(PointerRNA *ptr, PropertyRNA *prop);
-void *RNA_property_enum_py_data_get(PropertyRNA *prop);
 int RNA_property_enum_step(
     const struct bContext *C, PointerRNA *ptr, PropertyRNA *prop, int from_value, int step);
 
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)
diff --git a/source/blender/makesrna/intern/makesrna.c b/source/blender/makesrna/intern/makesrna.c
index 1f887c2eec3..6940e475f39 100644
--- a/source/blender/makesrna/intern/makesrna.c
+++ b/source/blender/makesrna/intern/makesrna.c
@@ -3989,7 +3989,7 @@ static void rna_generate_property(FILE *f, StructRNA *srna, const char *nest, Pr
     case PROP_ENUM: {
       EnumPropertyRNA *eprop = (EnumPropertyRNA *)prop;
       fprintf(f,
-              "\t%s, %s, %s, %s, %s, NULL, ",
+              "\t%s, %s, %s, %s, %s, ",
               rna_function_string(eprop->get),
               rna_function_string(eprop->set),
               rna_function_string(eprop->item_fn),
diff --git a/source/blender/makesrna/intern/rna_access.c b/source/blender/makesrna/intern/rna_access.c
index 8e5e70642cc..f94dc38ddfe 100644
--- a/source/blender/makesrna/intern/rna_access.c
+++ b/source/blender/makesrna/intern/rna_access.c
@@ -3598,15 +3598,6 @@ int RNA_property_enum_get_default(PointerRNA *UNUSED(ptr), PropertyRNA *prop)
   return eprop->defaultvalue;
 }
 
-void *RNA_property_enum_py_data_get(PropertyRNA *prop)
-{
-  EnumPropertyRNA *eprop = (EnumPropertyRNA *)prop;
-
-  BLI_assert(RNA_property_type(prop) == PROP_ENUM);
-
-  return eprop->py_data;
-}
-
 /**
  * Get the value of the item that is \a step items away from \a from_value.
  *
diff --git a/source/blender/makesrna/intern/rna_define.c b/source/blender/makesrna/intern/rna_define.c
index 5e188285e39..019823a7de3 100644
--- a/source/blender/makesrna/intern/rna_define.c
+++ b/source/blender/makesrna/intern/rna_define.c
@@ -3305,12 +3305,6 @@ void RNA_def_property_enum_funcs_runtime(PropertyRNA *prop,
   }
 }
 
-void RNA_def_property_enum_py_data(PropertyRNA *prop, void *py_data)
-{
-  EnumPropertyRNA *eprop = (EnumPropertyRNA *)prop;
-  eprop->py_data = py_data;
-}
-
 void RNA_def_property_string_funcs(PropertyRNA *prop,
                                    const char *get,
                                    const char *length,
@@ -4632,11 +4626,28 @@ void RNA_def_property_duplicate_pointers(StructOrFunctionRNA *cont_, PropertyRNA
   prop->flag_internal |= PROP_INTERN_FREE_POINTERS;
 }
 
+static void (*g_py_data_clear_fn)(PropertyRNA *prop) = NULL;
+
+/**
+ * Set the callback used to decrement the user count of a property.
+ *
+ * This function is called when freeing each dynamically defined property.
+ */
+void RNA_def_property_free_pointers_set_py_data_callback(
+    void (*py_data_clear_fn)(PropertyRNA *prop))
+{
+  g_py_data_clear_fn = py_data_clear_fn;
+}
+
 void RNA_def_property_free_pointers(PropertyRNA *prop)
 {
   if (prop->flag_internal & PROP_INTERN_FREE_POINTERS) {
     int a;
 
+    if (g_py_data_clear_fn) {
+      g_py_data_clear_fn(prop);
+    }
+
     if (prop->identifier) {
       MEM_freeN((void *)prop->identifier);
     }
diff --git a/source/blender/makesrna/intern/rna_internal_types.h b/source/blender/makesrna/intern/rna_internal_types.h
index 1dd08bb1074..0c0260c889c 100644
--- a/source/blender/makesrna/intern/rna_internal_types.h
+++ b/source/blender/makesrna/intern/rna_internal_types.h
@@ -457,7 +457,6 @@ typedef struct EnumPropertyRNA {
 
   PropEnumGetFuncEx get_ex;
   PropEnumSetFuncEx set_ex;
-  void *py_data; /* store py callback here */
 
   const EnumPropertyItem *item;
   int totitem;