Combine `LruCache.invalidate` and `invalidate_many` (#9973)

* Make `invalidate` and `invalidate_many` do the same thing

... so that we can do either over the invalidation replication stream, and also
because they always confused me a bit.

* Kill off `invalidate_many`

* changelog

1 files changed, 11 insertions, 7 deletions

diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 54df407ff7..d89e9d9b1d 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -152,7 +152,6 @@ class LruCache(Generic[KT, VT]):
     """
     Least-recently-used cache, supporting prometheus metrics and invalidation callbacks.
 
-    Supports del_multi only if cache_type=TreeCache
     If cache_type=TreeCache, all keys must be tuples.
     """
 
@@ -393,10 +392,16 @@ class LruCache(Generic[KT, VT]):
 
         @synchronized
         def cache_del_multi(key: KT) -> None:
+            """Delete an entry, or tree of entries
+
+            If the LruCache is backed by a regular dict, then "key" must be of
+            the right type for this cache
+
+            If the LruCache is backed by a TreeCache, then "key" must be a tuple, but
+            may be of lower cardinality than the TreeCache - in which case the whole
+            subtree is deleted.
             """
-            This will only work if constructed with cache_type=TreeCache
-            """
-            popped = cache.pop(key)
+            popped = cache.pop(key, None)
             if popped is None:
                 return
             # for each deleted node, we now need to remove it from the linked list
@@ -430,11 +435,10 @@ class LruCache(Generic[KT, VT]):
         self.set = cache_set
         self.setdefault = cache_set_default
         self.pop = cache_pop
+        self.del_multi = cache_del_multi
         # `invalidate` is exposed for consistency with DeferredCache, so that it can be
         # invalidated by the cache invalidation replication stream.
-        self.invalidate = cache_pop
-        if cache_type is TreeCache:
-            self.del_multi = cache_del_multi
+        self.invalidate = cache_del_multi
         self.len = synchronized(cache_len)
         self.contains = cache_contains
         self.clear = cache_clear