From ef68790fdbf9201b9d8ba8e36fb0d1394a9ec931 Mon Sep 17 00:00:00 2001
From: hauntsaninja <hauntsaninja@gmail.com>
Date: Sat, 16 Jul 2022 19:42:44 -0700
Subject: [PATCH] gh-93910: optimise enum attribute access
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This halves access to attributes such as methods or _sunder_ name

Benchmarked using:
```
from enum import Enum

class Color(Enum):
    RED = "Red"
    BLUE = "Blue"
    GREEN = "Green"

def f():
    for _ in range(1000):
        Color.RED
        Color.BLUE
        Color.GREEN

def g():
    for _ in range(1000):
        Color.RED._name_
        Color.BLUE._name_
        Color.GREEN._name_

import timeit
print(timeit.timeit('f()', number=10000, globals=globals()))
print(timeit.timeit('g()', number=10000, globals=globals()))
```

As of today morning:
```
6da988a46c λ ./python.exe bm_enum.py
1.499613167019561
1.5516562079428695
```

As of the latest enum change #94913:
```
c20186c397 λ ./python.exe bm_enum.py
1.4998537090141326
16.095267291995697
```

As of this PR:
```
gh-93910-micro λ ./python.exe bm_enum.py
1.4983433339511976
8.81327024998609
```
---
 Lib/enum.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Lib/enum.py b/Lib/enum.py
index a4f1f09adae01c..8582763cd2828c 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -1102,11 +1102,11 @@ def __init__(self, *args, **kwds):
         pass
 
     def __getattribute__(self, name):
-        self_dict = super().__getattribute__('__dict__')
-        cls = super().__getattribute__('__class__')
-        value = super().__getattribute__(name)
-        if isinstance(value, cls) and name not in self_dict and name in self._member_names_:
-            raise AttributeError("<enum '%s'> member has no attribute %r" % (cls.__name__, name))
+        if name in super().__getattribute__('_member_names_'):
+            value = super().__getattribute__(name)
+            cls = super().__getattribute__('__class__')
+            if isinstance(value, cls) and name not in super().__getattribute__('__dict__'):
+                raise AttributeError("<enum '%s'> member has no attribute %r" % (cls.__name__, name))
         return super().__getattribute__(name)
 
     def _generate_next_value_(name, start, count, last_values):