Use @lru_cache(maxsize=None) when appropriate (#1746)

For functions which do not take arguments, there is no need to limit the
maximum size of the cache used by @lru_cache (since it will never have
more than one entry).  By using @lru_cache(maxsize=None), a simpler,
faster cache implementation is used internally.

debug_toolbar/middleware.py

@@ -22,7 +22,7 @@ def show_toolbar(request):
     return settings.DEBUG and request.META.get("REMOTE_ADDR") in settings.INTERNAL_IPS
 
 
-@lru_cache
+@lru_cache(maxsize=None)
 def get_show_toolbar():
     # If SHOW_TOOLBAR_CALLBACK is a string, which is the recommended
     # setup, resolve it to the corresponding callable.

debug_toolbar/settings.py

@@ -45,7 +45,7 @@
 }
 
 
-@lru_cache
+@lru_cache(maxsize=None)
 def get_config():
     USER_CONFIG = getattr(settings, "DEBUG_TOOLBAR_CONFIG", {})
     CONFIG = CONFIG_DEFAULTS.copy()
@@ -70,7 +70,7 @@ def get_config():
 ]
 
 
-@lru_cache
+@lru_cache(maxsize=None)
 def get_panels():
     try:
         PANELS = list(settings.DEBUG_TOOLBAR_PANELS)

debug_toolbar/toolbar.py

@@ -166,7 +166,7 @@ def is_toolbar_request(cls, request):
         return resolver_match.namespaces and resolver_match.namespaces[-1] == APP_NAME
 
     @staticmethod
-    @lru_cache(maxsize=128)
+    @lru_cache(maxsize=None)
     def get_observe_request():
         # If OBSERVE_REQUEST_CALLBACK is a string, which is the recommended
         # setup, resolve it to the corresponding callable.