From bd1fdd4d903ae19251705b5ced4a019fd306a263 Mon Sep 17 00:00:00 2001
From: Noah <33094578+coolreader18@users.noreply.github.com>
Date: Thu, 2 Apr 2020 12:29:20 -0500
Subject: [PATCH] Call __set_name__ on descriptors when initializing types

---
 Lib/functools.py      |  3 ++-
 vm/src/obj/objtype.rs | 31 +++++++++++++++++++++++++------
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/Lib/functools.py b/Lib/functools.py
index b41dea7908..4cde5f590c 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -11,7 +11,8 @@
 
 __all__ = ['update_wrapper', 'wraps', 'WRAPPER_ASSIGNMENTS', 'WRAPPER_UPDATES',
            'total_ordering', 'cmp_to_key', 'lru_cache', 'reduce', 'partial',
-           'partialmethod', 'singledispatch', 'singledispatchmethod']
+           'partialmethod', 'singledispatch', 'singledispatchmethod',
+           "cached_property"]
 
 from abc import get_cache_token
 from collections import namedtuple
diff --git a/vm/src/obj/objtype.rs b/vm/src/obj/objtype.rs
index 49a0711c12..4391ff3e9a 100644
--- a/vm/src/obj/objtype.rs
+++ b/vm/src/obj/objtype.rs
@@ -291,14 +291,33 @@ impl PyClassRef {
             }
         }
 
-        match new(metatype, name.as_str(), base.clone(), bases, attributes) {
-            Ok(typ) => {
-                typ.slots.borrow_mut().flags = base.slots.borrow().flags;
-                vm.ctx.add_tp_new_wrapper(&typ);
-                Ok(typ.into())
+        let typ = new(metatype, name.as_str(), base.clone(), bases, attributes)
+            .map_err(|e| vm.new_type_error(e))?;
+
+        typ.slots.borrow_mut().flags = base.slots.borrow().flags;
+        vm.ctx.add_tp_new_wrapper(&typ);
+
+        for (name, obj) in typ.attributes.borrow().iter() {
+            if let Some(meth) = vm.get_method(obj.clone(), "__set_name__") {
+                let set_name = meth?;
+                vm.invoke(
+                    &set_name,
+                    vec![typ.clone().into_object(), vm.new_str(name.clone())],
+                )
+                .map_err(|e| {
+                    let err = vm.new_runtime_error(format!(
+                        "Error calling __set_name__ on '{}' instance {} in '{}'",
+                        obj.class().name,
+                        name,
+                        typ.name
+                    ));
+                    err.set_cause(Some(e));
+                    err
+                })?;
             }
-            Err(string) => Err(vm.new_type_error(string)),
         }
+
+        Ok(typ.into_object())
     }
 
     #[pyslot]