diff options
Diffstat (limited to 'synapse/util/caches/descriptors.py')
| -rw-r--r-- | synapse/util/caches/descriptors.py | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py index ac4a078b26..3a4d027095 100644 --- a/synapse/util/caches/descriptors.py +++ b/synapse/util/caches/descriptors.py @@ -322,8 +322,8 @@ class DeferredCacheDescriptor(_CacheDescriptorBase): class DeferredCacheListDescriptor(_CacheDescriptorBase): """Wraps an existing cache to support bulk fetching of keys. - Given a list of keys it looks in the cache to find any hits, then passes - the list of missing keys to the wrapped function. + Given an iterable of keys it looks in the cache to find any hits, then passes + the tuple of missing keys to the wrapped function. Once wrapped, the function returns a Deferred which resolves to the list of results. @@ -437,7 +437,9 @@ class DeferredCacheListDescriptor(_CacheDescriptorBase): return f args_to_call = dict(arg_dict) - args_to_call[self.list_name] = list(missing) + # copy the missing set before sending it to the callee, to guard against + # modification. + args_to_call[self.list_name] = tuple(missing) cached_defers.append( defer.maybeDeferred( @@ -522,14 +524,14 @@ def cachedList( Used to do batch lookups for an already created cache. A single argument is specified as a list that is iterated through to lookup keys in the - original cache. A new list consisting of the keys that weren't in the cache - get passed to the original function, the result of which is stored in the + original cache. A new tuple consisting of the (deduplicated) keys that weren't in + the cache gets passed to the original function, the result of which is stored in the cache. Args: cached_method_name: The name of the single-item lookup method. This is only used to find the cache to use. - list_name: The name of the argument that is the list to use to + list_name: The name of the argument that is the iterable to use to do batch lookups in the cache. num_args: Number of arguments to use as the key in the cache (including list_name). Defaults to all named parameters. |