Do not allow a None-limit on PaginationConfig. (#14146)

The callers either set a default limit or manually handle a None-limit
later on (by setting a default value).

Update the callers to always instantiate PaginationConfig with a default
limit and then assume the limit is non-None.

2 files changed, 6 insertions, 8 deletions

diff --git a/synapse/streams/__init__.py b/synapse/streams/__init__.py
index 806b671305..2dcd43d0a2 100644
--- a/synapse/streams/__init__.py
+++ b/synapse/streams/__init__.py
@@ -27,7 +27,7 @@ class EventSource(Generic[K, R]):
         self,
         user: UserID,
         from_key: K,
-        limit: Optional[int],
+        limit: int,
         room_ids: Collection[str],
         is_guest: bool,
         explicit_room_id: Optional[str] = None,
diff --git a/synapse/streams/config.py b/synapse/streams/config.py
index f6f7bf3d8b..6df2de919c 100644
--- a/synapse/streams/config.py
+++ b/synapse/streams/config.py
@@ -35,14 +35,14 @@ class PaginationConfig:
     from_token: Optional[StreamToken]
     to_token: Optional[StreamToken]
     direction: str
-    limit: Optional[int]
+    limit: int
 
     @classmethod
     async def from_request(
         cls,
         store: "DataStore",
         request: SynapseRequest,
-        default_limit: Optional[int] = None,
+        default_limit: int,
         default_dir: str = "f",
     ) -> "PaginationConfig":
         direction = parse_string(
@@ -69,12 +69,10 @@ class PaginationConfig:
             raise SynapseError(400, "'to' parameter is invalid")
 
         limit = parse_integer(request, "limit", default=default_limit)
+        if limit < 0:
+            raise SynapseError(400, "Limit must be 0 or above")
 
-        if limit:
-            if limit < 0:
-                raise SynapseError(400, "Limit must be 0 or above")
-
-            limit = min(int(limit), MAX_LIMIT)
+        limit = min(limit, MAX_LIMIT)
 
         try:
             return PaginationConfig(from_tok, to_tok, direction, limit)