Fixed #31675 -- Added warning to ExceptionReporter when exception chain has a cycle.

1 files changed, 10 insertions, 0 deletions

diff --git a/django/views/debug.py b/django/views/debug.py
index bc95cbf6b0..c85b86c913 100644
--- a/django/views/debug.py
+++ b/django/views/debug.py
@@ -2,6 +2,7 @@ import functools
 import re
 import sys
 import types
+import warnings
 from pathlib import Path
 
 from django.conf import settings
@@ -28,6 +29,10 @@ DEBUG_ENGINE = Engine(
 CURRENT_DIR = Path(__file__).parent
 
 
+class ExceptionCycleWarning(UserWarning):
+    pass
+
+
 class CallableSettingWrapper:
     """
     Object to wrap callable appearing in settings.
@@ -401,6 +406,11 @@ class ExceptionReporter:
             exceptions.append(exc_value)
             exc_value = explicit_or_implicit_cause(exc_value)
             if exc_value in exceptions:
+                warnings.warn(
+                    "Cycle in the exception chain detected: exception '%s' "
+                    "encountered again." % exc_value,
+                    ExceptionCycleWarning,
+                )
                 # Avoid infinite loop if there's a cyclic reference (#29393).
                 break