Only patch the cache methods once.

Author: tim-schilling

debug_toolbar/panels/cache.py

@@ -45,9 +45,13 @@ def wrapper(*args, **kwargs):
 
 
 def _monkey_patch_cache(cache, alias, panel):
-    if not getattr(cache, "_djdt_panel", None):
+    if not hasattr(cache, "_djdt_panel"):
+        # The panel has never been monkey patched before
         for name in WRAPPED_CACHE_METHODS:
             _monkey_patch_method(cache, name, alias)
+    if not getattr(cache, "_djdt_panel", None):
+        # This is used for both initially monkey patching and re-enabling the
+        # instrumentation.
         cache._djdt_panel = panel
 
 

docs/changes.rst

@@ -16,6 +16,8 @@ Pending
   rather than on instantiation.
 * Highlighted the documentation about disabling the browser's caching to
   ensure the latest static assets are used.
+* Fixed bug with ``CachePanel`` so the cache patching is only applied
+  once.
 
 6.2.0 (2026-01-20)
 ------------------

tests/panels/test_cache.py

@@ -158,3 +158,21 @@ def test_generate_server_timing(self):
     def test_backend_alias_is_recorded(self):
         cache.cache.get("foo")
         self.assertEqual(self.panel.calls[0]["backend"], "default (LocMemCache)")
+
+    def test_patching_only_applied_once(self):
+        """
+        Confirm that reapplying and disabling the cache patching only wraps
+        the cache methods once
+        """
+        for _ in range(2):
+            self.panel.enable_instrumentation()
+            self.panel.disable_instrumentation()
+        nested_wraps = 0
+        wrapped = cache.cache.get.__wrapped__
+        while wrapped is not None:
+            try:
+                wrapped = wrapped.__wrapped__
+                nested_wraps += 1
+            except AttributeError:
+                break
+        self.assertEqual(nested_wraps, 0)