Remove `keylen` from `LruCache`. (#9993)

`keylen` seems to be a thing that is frequently incorrectly set, and we don't really need it.

The only time it was used was to figure out if we had removed a subtree in `del_multi`, which we can do better by changing `TreeCache.pop` to return a different type (`TreeCacheNode`).

Commits should be independently reviewable.

2 files changed, 6 insertions, 4 deletions

diff --git a/tests/util/test_lrucache.py b/tests/util/test_lrucache.py
index df3e27779f..377904e72e 100644
--- a/tests/util/test_lrucache.py
+++ b/tests/util/test_lrucache.py
@@ -59,7 +59,7 @@ class LruCacheTestCase(unittest.HomeserverTestCase):
         self.assertEquals(cache.pop("key"), None)
 
     def test_del_multi(self):
-        cache = LruCache(4, keylen=2, cache_type=TreeCache)
+        cache = LruCache(4, cache_type=TreeCache)
         cache[("animal", "cat")] = "mew"
         cache[("animal", "dog")] = "woof"
         cache[("vehicles", "car")] = "vroom"
@@ -165,7 +165,7 @@ class LruCacheCallbacksTestCase(unittest.HomeserverTestCase):
         m2 = Mock()
         m3 = Mock()
         m4 = Mock()
-        cache = LruCache(4, keylen=2, cache_type=TreeCache)
+        cache = LruCache(4, cache_type=TreeCache)
 
         cache.set(("a", "1"), "value", callbacks=[m1])
         cache.set(("a", "2"), "value", callbacks=[m2])
diff --git a/tests/util/test_treecache.py b/tests/util/test_treecache.py
index 3b077af27e..6066372053 100644
--- a/tests/util/test_treecache.py
+++ b/tests/util/test_treecache.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 
-from synapse.util.caches.treecache import TreeCache
+from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
 
 from .. import unittest
 
@@ -64,12 +64,14 @@ class TreeCacheTestCase(unittest.TestCase):
         cache[("a", "b")] = "AB"
         cache[("b", "a")] = "BA"
         self.assertEquals(cache.get(("a", "a")), "AA")
-        cache.pop(("a",))
+        popped = cache.pop(("a",))
         self.assertEquals(cache.get(("a", "a")), None)
         self.assertEquals(cache.get(("a", "b")), None)
         self.assertEquals(cache.get(("b", "a")), "BA")
         self.assertEquals(len(cache), 1)
 
+        self.assertEquals({"AA", "AB"}, set(iterate_tree_cache_entry(popped)))
+
     def test_clear(self):
         cache = TreeCache()
         cache[("a",)] = "A"