More types for synapse.util, part 1 (#10888)

The following modules now pass `disallow_untyped_defs`:

* synapse.util.caches.cached_call 
* synapse.util.caches.lrucache
* synapse.util.caches.response_cache 
* synapse.util.caches.stream_change_cache
* synapse.util.caches.ttlcache pass
* synapse.util.daemonize
* synapse.util.patch_inline_callbacks pass `no-untyped-defs`
* synapse.util.versionstring

Additional typing in synapse.util.metrics. Didn't get this to pass `no-untyped-defs`, think I'll need to watch #10847

6 files changed, 45 insertions, 49 deletions

diff --git a/synapse/util/caches/cached_call.py b/synapse/util/caches/cached_call.py
index e58dd91eda..470f4f91a5 100644
--- a/synapse/util/caches/cached_call.py
+++ b/synapse/util/caches/cached_call.py
@@ -85,7 +85,7 @@ class CachedCall(Generic[TV]):
             # result in the deferred, since `awaiting` a deferred destroys its result.
             # (Also, if it's a Failure, GCing the deferred would log a critical error
             # about unhandled Failures)
-            def got_result(r):
+            def got_result(r: Union[TV, Failure]) -> None:
                 self._result = r
 
             self._deferred.addBoth(got_result)
diff --git a/synapse/util/caches/deferred_cache.py b/synapse/util/caches/deferred_cache.py
index 6262efe072..da502aec11 100644
--- a/synapse/util/caches/deferred_cache.py
+++ b/synapse/util/caches/deferred_cache.py
@@ -31,6 +31,7 @@ from prometheus_client import Gauge
 
 from twisted.internet import defer
 from twisted.python import failure
+from twisted.python.failure import Failure
 
 from synapse.util.async_helpers import ObservableDeferred
 from synapse.util.caches.lrucache import LruCache
@@ -112,7 +113,7 @@ class DeferredCache(Generic[KT, VT]):
         self.thread: Optional[threading.Thread] = None
 
     @property
-    def max_entries(self):
+    def max_entries(self) -> int:
         return self.cache.max_size
 
     def check_thread(self) -> None:
@@ -258,7 +259,7 @@ class DeferredCache(Generic[KT, VT]):
 
             return False
 
-        def cb(result) -> None:
+        def cb(result: VT) -> None:
             if compare_and_pop():
                 self.cache.set(key, result, entry.callbacks)
             else:
@@ -270,7 +271,7 @@ class DeferredCache(Generic[KT, VT]):
                 # not have been. Either way, let's double-check now.
                 entry.invalidate()
 
-        def eb(_fail) -> None:
+        def eb(_fail: Failure) -> None:
             compare_and_pop()
             entry.invalidate()
 
@@ -284,11 +285,11 @@ class DeferredCache(Generic[KT, VT]):
 
     def prefill(
         self, key: KT, value: VT, callback: Optional[Callable[[], None]] = None
-    ):
+    ) -> None:
         callbacks = [callback] if callback else []
         self.cache.set(key, value, callbacks=callbacks)
 
-    def invalidate(self, key):
+    def invalidate(self, key) -> None:
         """Delete a key, or tree of entries
 
         If the cache is backed by a regular dict, then "key" must be of
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 4ff62b403f..a0a7a9de32 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -52,7 +52,7 @@ logger = logging.getLogger(__name__)
 try:
     from pympler.asizeof import Asizer
 
-    def _get_size_of(val: Any, *, recurse=True) -> int:
+    def _get_size_of(val: Any, *, recurse: bool = True) -> int:
         """Get an estimate of the size in bytes of the object.
 
         Args:
@@ -71,7 +71,7 @@ try:
 
 except ImportError:
 
-    def _get_size_of(val: Any, *, recurse=True) -> int:
+    def _get_size_of(val: Any, *, recurse: bool = True) -> int:
         return 0
 
 
@@ -85,15 +85,6 @@ VT = TypeVar("VT")
 # a general type var, distinct from either KT or VT
 T = TypeVar("T")
 
-
-def enumerate_leaves(node, depth):
-    if depth == 0:
-        yield node
-    else:
-        for n in node.values():
-            yield from enumerate_leaves(n, depth - 1)
-
-
 P = TypeVar("P")
 
 
@@ -102,7 +93,7 @@ class _TimedListNode(ListNode[P]):
 
     __slots__ = ["last_access_ts_secs"]
 
-    def update_last_access(self, clock: Clock):
+    def update_last_access(self, clock: Clock) -> None:
         self.last_access_ts_secs = int(clock.time())
 
 
@@ -115,7 +106,7 @@ GLOBAL_ROOT = ListNode["_Node"].create_root_node()
 
 
 @wrap_as_background_process("LruCache._expire_old_entries")
-async def _expire_old_entries(clock: Clock, expiry_seconds: int):
+async def _expire_old_entries(clock: Clock, expiry_seconds: int) -> None:
     """Walks the global cache list to find cache entries that haven't been
     accessed in the given number of seconds.
     """
@@ -163,7 +154,7 @@ async def _expire_old_entries(clock: Clock, expiry_seconds: int):
     logger.info("Dropped %d items from caches", i)
 
 
-def setup_expire_lru_cache_entries(hs: "HomeServer"):
+def setup_expire_lru_cache_entries(hs: "HomeServer") -> None:
     """Start a background job that expires all cache entries if they have not
     been accessed for the given number of seconds.
     """
@@ -183,7 +174,7 @@ def setup_expire_lru_cache_entries(hs: "HomeServer"):
     )
 
 
-class _Node:
+class _Node(Generic[KT, VT]):
     __slots__ = [
         "_list_node",
         "_global_list_node",
@@ -197,8 +188,8 @@ class _Node:
     def __init__(
         self,
         root: "ListNode[_Node]",
-        key,
-        value,
+        key: KT,
+        value: VT,
         cache: "weakref.ReferenceType[LruCache]",
         clock: Clock,
         callbacks: Collection[Callable[[], None]] = (),
@@ -409,7 +400,7 @@ class LruCache(Generic[KT, VT]):
 
         def synchronized(f: FT) -> FT:
             @wraps(f)
-            def inner(*args, **kwargs):
+            def inner(*args: Any, **kwargs: Any) -> Any:
                 with lock:
                     return f(*args, **kwargs)
 
@@ -418,17 +409,19 @@ class LruCache(Generic[KT, VT]):
         cached_cache_len = [0]
         if size_callback is not None:
 
-            def cache_len():
+            def cache_len() -> int:
                 return cached_cache_len[0]
 
         else:
 
-            def cache_len():
+            def cache_len() -> int:
                 return len(cache)
 
         self.len = synchronized(cache_len)
 
-        def add_node(key, value, callbacks: Collection[Callable[[], None]] = ()):
+        def add_node(
+            key: KT, value: VT, callbacks: Collection[Callable[[], None]] = ()
+        ) -> None:
             node = _Node(
                 list_root,
                 key,
@@ -446,7 +439,7 @@ class LruCache(Generic[KT, VT]):
             if caches.TRACK_MEMORY_USAGE and metrics:
                 metrics.inc_memory_usage(node.memory)
 
-        def move_node_to_front(node: _Node):
+        def move_node_to_front(node: _Node) -> None:
             node.move_to_front(real_clock, list_root)
 
         def delete_node(node: _Node) -> int:
@@ -488,7 +481,7 @@ class LruCache(Generic[KT, VT]):
             default: Optional[T] = None,
             callbacks: Collection[Callable[[], None]] = (),
             update_metrics: bool = True,
-        ):
+        ) -> Union[None, T, VT]:
             node = cache.get(key, None)
             if node is not None:
                 move_node_to_front(node)
@@ -502,7 +495,9 @@ class LruCache(Generic[KT, VT]):
                 return default
 
         @synchronized
-        def cache_set(key: KT, value: VT, callbacks: Iterable[Callable[[], None]] = ()):
+        def cache_set(
+            key: KT, value: VT, callbacks: Iterable[Callable[[], None]] = ()
+        ) -> None:
             node = cache.get(key, None)
             if node is not None:
                 # We sometimes store large objects, e.g. dicts, which cause
@@ -547,7 +542,7 @@ class LruCache(Generic[KT, VT]):
             ...
 
         @synchronized
-        def cache_pop(key: KT, default: Optional[T] = None):
+        def cache_pop(key: KT, default: Optional[T] = None) -> Union[None, T, VT]:
             node = cache.get(key, None)
             if node:
                 delete_node(node)
@@ -612,25 +607,25 @@ class LruCache(Generic[KT, VT]):
         self.contains = cache_contains
         self.clear = cache_clear
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: KT) -> VT:
         result = self.get(key, self.sentinel)
         if result is self.sentinel:
             raise KeyError()
         else:
-            return result
+            return cast(VT, result)
 
-    def __setitem__(self, key, value):
+    def __setitem__(self, key: KT, value: VT) -> None:
         self.set(key, value)
 
-    def __delitem__(self, key, value):
+    def __delitem__(self, key: KT, value: VT) -> None:
         result = self.pop(key, self.sentinel)
         if result is self.sentinel:
             raise KeyError()
 
-    def __len__(self):
+    def __len__(self) -> int:
         return self.len()
 
-    def __contains__(self, key):
+    def __contains__(self, key: KT) -> bool:
         return self.contains(key)
 
     def set_cache_factor(self, factor: float) -> bool:
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index ed7204336f..88ccf44337 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -104,8 +104,8 @@ class ResponseCache(Generic[KV]):
             return None
 
     def _set(
-        self, context: ResponseCacheContext[KV], deferred: defer.Deferred
-    ) -> defer.Deferred:
+        self, context: ResponseCacheContext[KV], deferred: "defer.Deferred[RV]"
+    ) -> "defer.Deferred[RV]":
         """Set the entry for the given key to the given deferred.
 
         *deferred* should run its callbacks in the sentinel logcontext (ie,
@@ -126,7 +126,7 @@ class ResponseCache(Generic[KV]):
         key = context.cache_key
         self.pending_result_cache[key] = result
 
-        def on_complete(r):
+        def on_complete(r: RV) -> RV:
             # if this cache has a non-zero timeout, and the callback has not cleared
             # the should_cache bit, we leave it in the cache for now and schedule
             # its removal later.
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index 27b1da235e..330709b8b7 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -40,10 +40,10 @@ class StreamChangeCache:
         self,
         name: str,
         current_stream_pos: int,
-        max_size=10000,
+        max_size: int = 10000,
         prefilled_cache: Optional[Mapping[EntityType, int]] = None,
-    ):
-        self._original_max_size = max_size
+    ) -> None:
+        self._original_max_size: int = max_size
         self._max_size = math.floor(max_size)
         self._entity_to_key: Dict[EntityType, int] = {}
 
diff --git a/synapse/util/caches/ttlcache.py b/synapse/util/caches/ttlcache.py
index 46afe3f934..0b9ac26b69 100644
--- a/synapse/util/caches/ttlcache.py
+++ b/synapse/util/caches/ttlcache.py
@@ -159,12 +159,12 @@ class TTLCache(Generic[KT, VT]):
             del self._expiry_list[0]
 
 
-@attr.s(frozen=True, slots=True)
-class _CacheEntry:
+@attr.s(frozen=True, slots=True, auto_attribs=True)
+class _CacheEntry:  # Should be Generic[KT, VT]. See python-attrs/attrs#313
     """TTLCache entry"""
 
     # expiry_time is the first attribute, so that entries are sorted by expiry.
-    expiry_time = attr.ib(type=float)
-    ttl = attr.ib(type=float)
-    key = attr.ib()
-    value = attr.ib()
+    expiry_time: float
+    ttl: float
+    key: Any  # should be KT
+    value: Any  # should be VT