Fix cache panel miss counting

debug_toolbar/panels/cache.py

@@ -101,11 +101,12 @@ def _store_call_info(
             else:
                 self.hits += 1
         elif name == "get_many":
-            for key, value in return_value.items():
-                if value is None:
-                    self.misses += 1
-                else:
-                    self.hits += 1
+            if "keys" in kwargs:
+                keys = kwargs["keys"]
+            else:
+                keys = args[0]
+            self.hits += len(return_value)
+            self.misses += len(keys) - len(return_value)
         time_taken *= 1000
 
         self.total_time += time_taken

docs/changes.rst

@@ -8,6 +8,8 @@ Change log
   instances isn't a valid use of Django but, again, django-debug-toolbar
   shouldn't crash.
 * Added pyflame (for flame graphs) to the list of third-party panels.
+* Fixed the cache panel to correctly count cache misses from the get_many()
+  cache method.
 
 3.4.0 (2022-05-03)
 ------------------

tests/panels/test_cache.py

@@ -26,6 +26,23 @@ def test_recording_caches(self):
         second_cache.get("foo")
         self.assertEqual(len(self.panel.calls), 2)
 
+    def test_hits_and_misses(self):
+        cache.cache.clear()
+        cache.cache.get("foo")
+        self.assertEqual(self.panel.hits, 0)
+        self.assertEqual(self.panel.misses, 1)
+        cache.cache.set("foo", 1)
+        cache.cache.get("foo")
+        self.assertEqual(self.panel.hits, 1)
+        self.assertEqual(self.panel.misses, 1)
+        cache.cache.get_many(["foo", "bar"])
+        self.assertEqual(self.panel.hits, 2)
+        self.assertEqual(self.panel.misses, 2)
+        cache.cache.set("bar", 2)
+        cache.cache.get_many(keys=["foo", "bar"])
+        self.assertEqual(self.panel.hits, 4)
+        self.assertEqual(self.panel.misses, 2)
+
     def test_get_or_set_value(self):
         cache.cache.get_or_set("baz", "val")
         self.assertEqual(cache.cache.get("baz"), "val")