From 8cfcf9a30edd3ec0447af6a493b16d21e298e4e0 Mon Sep 17 00:00:00 2001
From: Sarah Boyce <42296566+sarahboyce@users.noreply.github.com>
Date: Fri, 28 Jun 2024 13:35:58 +0200
Subject: [PATCH] Reverted "Fixed #35564 -- Improved readability of subclass
 identification."

This reverts commit f0d05a747f7a099e6c6bc58c42a787546d2212e7 due to a performance regression.
---
 django/contrib/admin/checks.py | 16 ++++++++++------
 django/contrib/auth/checks.py  | 12 +++++++-----
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/django/contrib/admin/checks.py b/django/contrib/admin/checks.py
index 9937273c28..94e700cf68 100644
--- a/django/contrib/admin/checks.py
+++ b/django/contrib/admin/checks.py
@@ -1,5 +1,4 @@
 import collections
-import contextlib
 from itertools import chain
 
 from django.apps import apps
@@ -22,9 +21,10 @@ def _issubclass(cls, classinfo):
     issubclass() variant that doesn't raise an exception if cls isn't a
     class.
     """
-    with contextlib.suppress(TypeError):
+    try:
         return issubclass(cls, classinfo)
-    return False
+    except TypeError:
+        return False
 
 
 def _contains_subclass(class_path, candidate_paths):
@@ -34,9 +34,13 @@ def _contains_subclass(class_path, candidate_paths):
     """
     cls = import_string(class_path)
     for path in candidate_paths:
-        with contextlib.suppress(ImportError, TypeError):
-            if issubclass(import_string(path), cls):
-                return True
+        try:
+            candidate_cls = import_string(path)
+        except ImportError:
+            # ImportErrors are raised elsewhere.
+            continue
+        if _issubclass(candidate_cls, cls):
+            return True
     return False
 
 
diff --git a/django/contrib/auth/checks.py b/django/contrib/auth/checks.py
index 61da4f293a..f2f9a74a6c 100644
--- a/django/contrib/auth/checks.py
+++ b/django/contrib/auth/checks.py
@@ -1,4 +1,3 @@
-import contextlib
 from itertools import chain
 from types import MethodType
 
@@ -16,10 +15,13 @@ def _subclass_index(class_path, candidate_paths):
     list of candidate paths. If it does not exist, return -1.
     """
     cls = import_string(class_path)
-    for i, path in enumerate(candidate_paths):
-        with contextlib.suppress(ImportError, TypeError):
-            if issubclass(import_string(path), cls):
-                return i
+    for index, path in enumerate(candidate_paths):
+        try:
+            candidate_cls = import_string(path)
+            if issubclass(candidate_cls, cls):
+                return index
+        except (ImportError, TypeError):
+            continue
     return -1