Convert all namedtuples to attrs. (#11665)

To improve type hints throughout the code.

20 files changed, 225 insertions, 205 deletions

diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index 13dd6ce248..d087c816db 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -351,8 +351,7 @@ class Filter:
             True if the event matches the filter.
         """
         # We usually get the full "events" as dictionaries coming through,
-        # except for presence which actually gets passed around as its own
-        # namedtuple type.
+        # except for presence which actually gets passed around as its own type.
         if isinstance(event, UserPresenceState):
             user_id = event.user_id
             field_matchers = {
diff --git a/synapse/config/repository.py b/synapse/config/repository.py
index b129b9dd68..1980351e77 100644
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@@ -14,10 +14,11 @@
 
 import logging
 import os
-from collections import namedtuple
 from typing import Dict, List, Tuple
 from urllib.request import getproxies_environment  # type: ignore
 
+import attr
+
 from synapse.config.server import DEFAULT_IP_RANGE_BLACKLIST, generate_ip_set
 from synapse.python_dependencies import DependencyException, check_requirements
 from synapse.types import JsonDict
@@ -44,18 +45,20 @@ THUMBNAIL_SIZE_YAML = """\
 HTTP_PROXY_SET_WARNING = """\
 The Synapse config url_preview_ip_range_blacklist will be ignored as an HTTP(s) proxy is configured."""
 
-ThumbnailRequirement = namedtuple(
-    "ThumbnailRequirement", ["width", "height", "method", "media_type"]
-)
 
-MediaStorageProviderConfig = namedtuple(
-    "MediaStorageProviderConfig",
-    (
-        "store_local",  # Whether to store newly uploaded local files
-        "store_remote",  # Whether to store newly downloaded remote files
-        "store_synchronous",  # Whether to wait for successful storage for local uploads
-    ),
-)
+@attr.s(frozen=True, slots=True, auto_attribs=True)
+class ThumbnailRequirement:
+    width: int
+    height: int
+    method: str
+    media_type: str
+
+
+@attr.s(frozen=True, slots=True, auto_attribs=True)
+class MediaStorageProviderConfig:
+    store_local: bool  # Whether to store newly uploaded local files
+    store_remote: bool  # Whether to store newly downloaded remote files
+    store_synchronous: bool  # Whether to wait for successful storage for local uploads
 
 
 def parse_thumbnail_requirements(
@@ -66,11 +69,10 @@ def parse_thumbnail_requirements(
     method, and thumbnail media type to precalculate
 
     Args:
-        thumbnail_sizes(list): List of dicts with "width", "height", and
-            "method" keys
+        thumbnail_sizes: List of dicts with "width", "height", and "method" keys
+
     Returns:
-        Dictionary mapping from media type string to list of
-        ThumbnailRequirement tuples.
+        Dictionary mapping from media type string to list of ThumbnailRequirement.
     """
     requirements: Dict[str, List[ThumbnailRequirement]] = {}
     for size in thumbnail_sizes:
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index f56344a3b9..4df90e02d7 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from collections import namedtuple
 from typing import TYPE_CHECKING
 
 from synapse.api.constants import MAX_DEPTH, EventContentFields, EventTypes, Membership
@@ -104,10 +103,6 @@ class FederationBase:
         return pdu
 
 
-class PduToCheckSig(namedtuple("PduToCheckSig", ["pdu", "sender_domain", "deferreds"])):
-    pass
-
-
 async def _check_sigs_on_pdu(
     keyring: Keyring, room_version: RoomVersion, pdu: EventBase
 ) -> None:
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 63289a5a33..0d7c4f5067 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -30,7 +30,6 @@ Events are replicated via a separate events stream.
 """
 
 import logging
-from collections import namedtuple
 from typing import (
     TYPE_CHECKING,
     Dict,
@@ -43,6 +42,7 @@ from typing import (
     Type,
 )
 
+import attr
 from sortedcontainers import SortedDict
 
 from synapse.api.presence import UserPresenceState
@@ -382,13 +382,11 @@ class BaseFederationRow:
         raise NotImplementedError()
 
 
-class PresenceDestinationsRow(
-    BaseFederationRow,
-    namedtuple(
-        "PresenceDestinationsRow",
-        ("state", "destinations"),  # UserPresenceState  # list[str]
-    ),
-):
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class PresenceDestinationsRow(BaseFederationRow):
+    state: UserPresenceState
+    destinations: List[str]
+
     TypeId = "pd"
 
     @staticmethod
@@ -404,17 +402,15 @@ class PresenceDestinationsRow(
         buff.presence_destinations.append((self.state, self.destinations))
 
 
-class KeyedEduRow(
-    BaseFederationRow,
-    namedtuple(
-        "KeyedEduRow",
-        ("key", "edu"),  # tuple(str) - the edu key passed to send_edu  # Edu
-    ),
-):
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class KeyedEduRow(BaseFederationRow):
     """Streams EDUs that have an associated key that is ued to clobber. For example,
     typing EDUs clobber based on room_id.
     """
 
+    key: Tuple[str, ...]  # the edu key passed to send_edu
+    edu: Edu
+
     TypeId = "k"
 
     @staticmethod
@@ -428,9 +424,12 @@ class KeyedEduRow(
         buff.keyed_edus.setdefault(self.edu.destination, {})[self.key] = self.edu
 
 
-class EduRow(BaseFederationRow, namedtuple("EduRow", ("edu",))):  # Edu
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class EduRow(BaseFederationRow):
     """Streams EDUs that don't have keys. See KeyedEduRow"""
 
+    edu: Edu
+
     TypeId = "e"
 
     @staticmethod
@@ -453,14 +452,14 @@ _rowtypes: Tuple[Type[BaseFederationRow], ...] = (
 TypeToRow = {Row.TypeId: Row for Row in _rowtypes}
 
 
-ParsedFederationStreamData = namedtuple(
-    "ParsedFederationStreamData",
-    (
-        "presence_destinations",  # list of tuples of UserPresenceState and destinations
-        "keyed_edus",  # dict of destination -> { key -> Edu }
-        "edus",  # dict of destination -> [Edu]
-    ),
-)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class ParsedFederationStreamData:
+    # list of tuples of UserPresenceState and destinations
+    presence_destinations: List[Tuple[UserPresenceState, List[str]]]
+    # dict of destination -> { key -> Edu }
+    keyed_edus: Dict[str, Dict[Tuple[str, ...], Edu]]
+    # dict of destination -> [Edu]
+    edus: Dict[str, List[Edu]]
 
 
 def process_rows_for_federation(
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 9abdad262b..7833e77e2b 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -462,9 +462,9 @@ class ApplicationServicesHandler:
 
         Args:
             room_alias: The room alias to query.
+
         Returns:
-            namedtuple: with keys "room_id" and "servers" or None if no
-            association can be found.
+            RoomAliasMapping or None if no association can be found.
         """
         room_alias_str = room_alias.to_string()
         services = self.store.get_app_services()
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 7ee5c47fd9..082f521791 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -278,13 +278,15 @@ class DirectoryHandler:
 
         users = await self.store.get_users_in_room(room_id)
         extra_servers = {get_domain_from_id(u) for u in users}
-        servers = set(extra_servers) | set(servers)
+        servers_set = set(extra_servers) | set(servers)
 
         # If this server is in the list of servers, return it first.
-        if self.server_name in servers:
-            servers = [self.server_name] + [s for s in servers if s != self.server_name]
+        if self.server_name in servers_set:
+            servers = [self.server_name] + [
+                s for s in servers_set if s != self.server_name
+            ]
         else:
-            servers = list(servers)
+            servers = list(servers_set)
 
         return {"room_id": room_id, "servers": servers}
 
diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index ba7a14d651..1a33211a1f 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -13,9 +13,9 @@
 # limitations under the License.
 
 import logging
-from collections import namedtuple
 from typing import TYPE_CHECKING, Any, Optional, Tuple
 
+import attr
 import msgpack
 from unpaddedbase64 import decode_base64, encode_base64
 
@@ -474,16 +474,12 @@ class RoomListHandler:
         )
 
 
-class RoomListNextBatch(
-    namedtuple(
-        "RoomListNextBatch",
-        (
-            "last_joined_members",  # The count to get rooms after/before
-            "last_room_id",  # The room_id to get rooms after/before
-            "direction_is_forward",  # Bool if this is a next_batch, false if prev_batch
-        ),
-    )
-):
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class RoomListNextBatch:
+    last_joined_members: int  # The count to get rooms after/before
+    last_room_id: str  # The room_id to get rooms after/before
+    direction_is_forward: bool  # True if this is a next_batch, false if prev_batch
+
     KEY_DICT = {
         "last_joined_members": "m",
         "last_room_id": "r",
@@ -502,12 +498,12 @@ class RoomListNextBatch(
     def to_token(self) -> str:
         return encode_base64(
             msgpack.dumps(
-                {self.KEY_DICT[key]: val for key, val in self._asdict().items()}
+                {self.KEY_DICT[key]: val for key, val in attr.asdict(self).items()}
             )
         )
 
     def copy_and_replace(self, **kwds: Any) -> "RoomListNextBatch":
-        return self._replace(**kwds)
+        return attr.evolve(self, **kwds)
 
 
 def _matches_room_entry(room_entry: JsonDict, search_filter: dict) -> bool:
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 1676ebd057..e43c22832d 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -13,9 +13,10 @@
 # limitations under the License.
 import logging
 import random
-from collections import namedtuple
 from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Set, Tuple
 
+import attr
+
 from synapse.api.errors import AuthError, ShadowBanError, SynapseError
 from synapse.appservice import ApplicationService
 from synapse.metrics.background_process_metrics import (
@@ -37,7 +38,10 @@ logger = logging.getLogger(__name__)
 
 # A tiny object useful for storing a user's membership in a room, as a mapping
 # key
-RoomMember = namedtuple("RoomMember", ("room_id", "user_id"))
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class RoomMember:
+    room_id: str
+    user_id: str
 
 
 # How often we expect remote servers to resend us presence.
@@ -119,7 +123,7 @@ class FollowerTypingHandler:
         self.wheel_timer.insert(now=now, obj=member, then=now + 60 * 1000)
 
     def is_typing(self, member: RoomMember) -> bool:
-        return member.user_id in self._room_typing.get(member.room_id, [])
+        return member.user_id in self._room_typing.get(member.room_id, set())
 
     async def _push_remote(self, member: RoomMember, typing: bool) -> None:
         if not self.federation:
@@ -166,9 +170,9 @@ class FollowerTypingHandler:
         for row in rows:
             self._room_serials[row.room_id] = token
 
-            prev_typing = set(self._room_typing.get(row.room_id, []))
+            prev_typing = self._room_typing.get(row.room_id, set())
             now_typing = set(row.user_ids)
-            self._room_typing[row.room_id] = row.user_ids
+            self._room_typing[row.room_id] = now_typing
 
             if self.federation:
                 run_as_background_process(
diff --git a/synapse/http/server.py b/synapse/http/server.py
index e302946591..09b4125489 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -14,7 +14,6 @@
 # limitations under the License.
 
 import abc
-import collections
 import html
 import logging
 import types
@@ -37,6 +36,7 @@ from typing import (
     Union,
 )
 
+import attr
 import jinja2
 from canonicaljson import encode_canonical_json
 from typing_extensions import Protocol
@@ -354,9 +354,11 @@ class DirectServeJsonResource(_AsyncResource):
         return_json_error(f, request)
 
 
-_PathEntry = collections.namedtuple(
-    "_PathEntry", ["pattern", "callback", "servlet_classname"]
-)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class _PathEntry:
+    pattern: Pattern
+    callback: ServletCallback
+    servlet_classname: str
 
 
 class JsonResource(DirectServeJsonResource):
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index 743a01da08..5a2d90c530 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -15,7 +15,6 @@
 
 import heapq
 import logging
-from collections import namedtuple
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -30,6 +29,7 @@ from typing import (
 import attr
 
 from synapse.replication.http.streams import ReplicationGetStreamUpdates
+from synapse.types import JsonDict
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -226,17 +226,14 @@ class BackfillStream(Stream):
     or it went from being an outlier to not.
     """
 
-    BackfillStreamRow = namedtuple(
-        "BackfillStreamRow",
-        (
-            "event_id",  # str
-            "room_id",  # str
-            "type",  # str
-            "state_key",  # str, optional
-            "redacts",  # str, optional
-            "relates_to",  # str, optional
-        ),
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class BackfillStreamRow:
+        event_id: str
+        room_id: str
+        type: str
+        state_key: Optional[str]
+        redacts: Optional[str]
+        relates_to: Optional[str]
 
     NAME = "backfill"
     ROW_TYPE = BackfillStreamRow
@@ -256,18 +253,15 @@ class BackfillStream(Stream):
 
 
 class PresenceStream(Stream):
-    PresenceStreamRow = namedtuple(
-        "PresenceStreamRow",
-        (
-            "user_id",  # str
-            "state",  # str
-            "last_active_ts",  # int
-            "last_federation_update_ts",  # int
-            "last_user_sync_ts",  # int
-            "status_msg",  # str
-            "currently_active",  # bool
-        ),
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class PresenceStreamRow:
+        user_id: str
+        state: str
+        last_active_ts: int
+        last_federation_update_ts: int
+        last_user_sync_ts: int
+        status_msg: str
+        currently_active: bool
 
     NAME = "presence"
     ROW_TYPE = PresenceStreamRow
@@ -302,7 +296,7 @@ class PresenceFederationStream(Stream):
     send.
     """
 
-    @attr.s(slots=True, auto_attribs=True)
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
     class PresenceFederationStreamRow:
         destination: str
         user_id: str
@@ -320,9 +314,10 @@ class PresenceFederationStream(Stream):
 
 
 class TypingStream(Stream):
-    TypingStreamRow = namedtuple(
-        "TypingStreamRow", ("room_id", "user_ids")  # str  # list(str)
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class TypingStreamRow:
+        room_id: str
+        user_ids: List[str]
 
     NAME = "typing"
     ROW_TYPE = TypingStreamRow
@@ -348,16 +343,13 @@ class TypingStream(Stream):
 
 
 class ReceiptsStream(Stream):
-    ReceiptsStreamRow = namedtuple(
-        "ReceiptsStreamRow",
-        (
-            "room_id",  # str
-            "receipt_type",  # str
-            "user_id",  # str
-            "event_id",  # str
-            "data",  # dict
-        ),
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class ReceiptsStreamRow:
+        room_id: str
+        receipt_type: str
+        user_id: str
+        event_id: str
+        data: dict
 
     NAME = "receipts"
     ROW_TYPE = ReceiptsStreamRow
@@ -374,7 +366,9 @@ class ReceiptsStream(Stream):
 class PushRulesStream(Stream):
     """A user has changed their push rules"""
 
-    PushRulesStreamRow = namedtuple("PushRulesStreamRow", ("user_id",))  # str
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class PushRulesStreamRow:
+        user_id: str
 
     NAME = "push_rules"
     ROW_TYPE = PushRulesStreamRow
@@ -396,10 +390,12 @@ class PushRulesStream(Stream):
 class PushersStream(Stream):
     """A user has added/changed/removed a pusher"""
 
-    PushersStreamRow = namedtuple(
-        "PushersStreamRow",
-        ("user_id", "app_id", "pushkey", "deleted"),  # str  # str  # str  # bool
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class PushersStreamRow:
+        user_id: str
+        app_id: str
+        pushkey: str
+        deleted: bool
 
     NAME = "pushers"
     ROW_TYPE = PushersStreamRow
@@ -419,7 +415,7 @@ class CachesStream(Stream):
     the cache on the workers
     """
 
-    @attr.s(slots=True)
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
     class CachesStreamRow:
         """Stream to inform workers they should invalidate their cache.
 
@@ -430,9 +426,9 @@ class CachesStream(Stream):
             invalidation_ts: Timestamp of when the invalidation took place.
         """
 
-        cache_func = attr.ib(type=str)
-        keys = attr.ib(type=Optional[List[Any]])
-        invalidation_ts = attr.ib(type=int)
+        cache_func: str
+        keys: Optional[List[Any]]
+        invalidation_ts: int
 
     NAME = "caches"
     ROW_TYPE = CachesStreamRow
@@ -451,9 +447,9 @@ class DeviceListsStream(Stream):
     told about a device update.
     """
 
-    @attr.s(slots=True)
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
     class DeviceListsStreamRow:
-        entity = attr.ib(type=str)
+        entity: str
 
     NAME = "device_lists"
     ROW_TYPE = DeviceListsStreamRow
@@ -470,7 +466,9 @@ class DeviceListsStream(Stream):
 class ToDeviceStream(Stream):
     """New to_device messages for a client"""
 
-    ToDeviceStreamRow = namedtuple("ToDeviceStreamRow", ("entity",))  # str
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class ToDeviceStreamRow:
+        entity: str
 
     NAME = "to_device"
     ROW_TYPE = ToDeviceStreamRow
@@ -487,9 +485,11 @@ class ToDeviceStream(Stream):
 class TagAccountDataStream(Stream):
     """Someone added/removed a tag for a room"""
 
-    TagAccountDataStreamRow = namedtuple(
-        "TagAccountDataStreamRow", ("user_id", "room_id", "data")  # str  # str  # dict
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class TagAccountDataStreamRow:
+        user_id: str
+        room_id: str
+        data: JsonDict
 
     NAME = "tag_account_data"
     ROW_TYPE = TagAccountDataStreamRow
@@ -506,10 +506,11 @@ class TagAccountDataStream(Stream):
 class AccountDataStream(Stream):
     """Global or per room account data was changed"""
 
-    AccountDataStreamRow = namedtuple(
-        "AccountDataStreamRow",
-        ("user_id", "room_id", "data_type"),  # str  # Optional[str]  # str
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class AccountDataStreamRow:
+        user_id: str
+        room_id: Optional[str]
+        data_type: str
 
     NAME = "account_data"
     ROW_TYPE = AccountDataStreamRow
@@ -573,10 +574,12 @@ class AccountDataStream(Stream):
 
 
 class GroupServerStream(Stream):
-    GroupsStreamRow = namedtuple(
-        "GroupsStreamRow",
-        ("group_id", "user_id", "type", "content"),  # str  # str  # str  # dict
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class GroupsStreamRow:
+        group_id: str
+        user_id: str
+        type: str
+        content: JsonDict
 
     NAME = "groups"
     ROW_TYPE = GroupsStreamRow
@@ -593,7 +596,9 @@ class GroupServerStream(Stream):
 class UserSignatureStream(Stream):
     """A user has signed their own device with their user-signing key"""
 
-    UserSignatureStreamRow = namedtuple("UserSignatureStreamRow", ("user_id"))  # str
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class UserSignatureStreamRow:
+        user_id: str
 
     NAME = "user_signature"
     ROW_TYPE = UserSignatureStreamRow
diff --git a/synapse/replication/tcp/streams/federation.py b/synapse/replication/tcp/streams/federation.py
index 0600cdbf36..4046bdec69 100644
--- a/synapse/replication/tcp/streams/federation.py
+++ b/synapse/replication/tcp/streams/federation.py
@@ -12,14 +12,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from collections import namedtuple
 from typing import TYPE_CHECKING, Any, Awaitable, Callable, List, Tuple
 
+import attr
+
 from synapse.replication.tcp.streams._base import (
     Stream,
     current_token_without_instance,
     make_http_update_function,
 )
+from synapse.types import JsonDict
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -30,13 +32,10 @@ class FederationStream(Stream):
     sending disabled.
     """
 
-    FederationStreamRow = namedtuple(
-        "FederationStreamRow",
-        (
-            "type",  # str, the type of data as defined in the BaseFederationRows
-            "data",  # dict, serialization of a federation.send_queue.BaseFederationRow
-        ),
-    )
+    @attr.s(slots=True, frozen=True, auto_attribs=True)
+    class FederationStreamRow:
+        type: str  # the type of data as defined in the BaseFederationRows
+        data: JsonDict  # serialization of a federation.send_queue.BaseFederationRow
 
     NAME = "federation"
     ROW_TYPE = FederationStreamRow
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 244ba261bb..71b9a34b14 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -739,14 +739,21 @@ class MediaRepository:
         # We deduplicate the thumbnail sizes by ignoring the cropped versions if
         # they have the same dimensions of a scaled one.
         thumbnails: Dict[Tuple[int, int, str], str] = {}
-        for r_width, r_height, r_method, r_type in requirements:
-            if r_method == "crop":
-                thumbnails.setdefault((r_width, r_height, r_type), r_method)
-            elif r_method == "scale":
-                t_width, t_height = thumbnailer.aspect(r_width, r_height)
+        for requirement in requirements:
+            if requirement.method == "crop":
+                thumbnails.setdefault(
+                    (requirement.width, requirement.height, requirement.media_type),
+                    requirement.method,
+                )
+            elif requirement.method == "scale":
+                t_width, t_height = thumbnailer.aspect(
+                    requirement.width, requirement.height
+                )
                 t_width = min(m_width, t_width)
                 t_height = min(m_height, t_height)
-                thumbnails[(t_width, t_height, r_type)] = r_method
+                thumbnails[
+                    (t_width, t_height, requirement.media_type)
+                ] = requirement.method
 
         # Now we generate the thumbnails for each dimension, store it
         for (t_width, t_height, t_type), t_method in thumbnails.items():
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index 446204dbe5..69ac8c3423 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 import heapq
 import logging
-from collections import defaultdict, namedtuple
+from collections import defaultdict
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -69,9 +69,6 @@ state_groups_histogram = Histogram(
 )
 
 
-KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
-
-
 EVICTION_TIMEOUT_SECONDS = 60 * 60
 
 
diff --git a/synapse/storage/databases/main/directory.py b/synapse/storage/databases/main/directory.py
index a3442814d7..f76c6121e8 100644
--- a/synapse/storage/databases/main/directory.py
+++ b/synapse/storage/databases/main/directory.py
@@ -12,16 +12,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from collections import namedtuple
 from typing import Iterable, List, Optional, Tuple
 
+import attr
+
 from synapse.api.errors import SynapseError
 from synapse.storage.database import LoggingTransaction
 from synapse.storage.databases.main import CacheInvalidationWorkerStore
 from synapse.types import RoomAlias
 from synapse.util.caches.descriptors import cached
 
-RoomAliasMapping = namedtuple("RoomAliasMapping", ("room_id", "room_alias", "servers"))
+
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class RoomAliasMapping:
+    room_id: str
+    room_alias: str
+    servers: List[str]
 
 
 class DirectoryWorkerStore(CacheInvalidationWorkerStore):
diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 81e67ece55..dd255aefb9 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -1976,14 +1976,17 @@ class PersistEventsStore:
                 txn, self.store.get_retention_policy_for_room, (event.room_id,)
             )
 
-    def store_event_search_txn(self, txn, event, key, value):
+    def store_event_search_txn(
+        self, txn: LoggingTransaction, event: EventBase, key: str, value: str
+    ) -> None:
         """Add event to the search table
 
         Args:
-            txn (cursor):
-            event (EventBase):
-            key (str):
-            value (str):
+            txn: The database transaction.
+            event: The event being added to the search table.
+            key: A key describing the search value (one of "content.name",
+                "content.topic", or "content.body")
+            value: The value from the event's content.
         """
         self.store.store_search_entries_txn(
             txn,
diff --git a/synapse/storage/databases/main/room.py b/synapse/storage/databases/main/room.py
index 4472335af9..c0e837854a 100644
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -13,11 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import collections
 import logging
 from abc import abstractmethod
 from enum import Enum
-from typing import TYPE_CHECKING, Any, Awaitable, Dict, List, Optional, Tuple, cast
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Awaitable,
+    Dict,
+    List,
+    Optional,
+    Tuple,
+    Union,
+    cast,
+)
+
+import attr
 
 from synapse.api.constants import EventContentFields, EventTypes, JoinRules
 from synapse.api.errors import StoreError
@@ -43,9 +54,10 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-RatelimitOverride = collections.namedtuple(
-    "RatelimitOverride", ("messages_per_second", "burst_count")
-)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class RatelimitOverride:
+    messages_per_second: int
+    burst_count: int
 
 
 class RoomSortOrder(Enum):
@@ -207,6 +219,7 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
                         WHERE appservice_id = ? AND network_id = ?
                     """
                     query_args.append(network_tuple.appservice_id)
+                    assert network_tuple.network_id is not None
                     query_args.append(network_tuple.network_id)
                 else:
                     published_sql = """
@@ -284,7 +297,7 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
         """
 
         where_clauses = []
-        query_args = []
+        query_args: List[Union[str, int]] = []
 
         if network_tuple:
             if network_tuple.appservice_id:
@@ -293,6 +306,7 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
                     WHERE appservice_id = ? AND network_id = ?
                 """
                 query_args.append(network_tuple.appservice_id)
+                assert network_tuple.network_id is not None
                 query_args.append(network_tuple.network_id)
             else:
                 published_sql = """
diff --git a/synapse/storage/databases/main/search.py b/synapse/storage/databases/main/search.py
index f87acfb866..2d085a5764 100644
--- a/synapse/storage/databases/main/search.py
+++ b/synapse/storage/databases/main/search.py
@@ -14,9 +14,10 @@
 
 import logging
 import re
-from collections import namedtuple
 from typing import TYPE_CHECKING, Collection, Iterable, List, Optional, Set
 
+import attr
+
 from synapse.api.errors import SynapseError
 from synapse.events import EventBase
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
@@ -33,10 +34,15 @@ if TYPE_CHECKING:
 
 logger = logging.getLogger(__name__)
 
-SearchEntry = namedtuple(
-    "SearchEntry",
-    ["key", "value", "event_id", "room_id", "stream_ordering", "origin_server_ts"],
-)
+
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class SearchEntry:
+    key: str
+    value: str
+    event_id: str
+    room_id: str
+    stream_ordering: Optional[int]
+    origin_server_ts: int
 
 
 def _clean_value_for_search(value: str) -> str:
diff --git a/synapse/storage/databases/main/state.py b/synapse/storage/databases/main/state.py
index 4bc044fb16..7e5a6aae18 100644
--- a/synapse/storage/databases/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -14,7 +14,6 @@
 # limitations under the License.
 import collections.abc
 import logging
-from collections import namedtuple
 from typing import TYPE_CHECKING, Iterable, Optional, Set
 
 from synapse.api.constants import EventTypes, Membership
@@ -43,19 +42,6 @@ logger = logging.getLogger(__name__)
 MAX_STATE_DELTA_HOPS = 100
 
 
-class _GetStateGroupDelta(
-    namedtuple("_GetStateGroupDelta", ("prev_group", "delta_ids"))
-):
-    """Return type of get_state_group_delta that implements __len__, which lets
-    us use the itrable flag when caching
-    """
-
-    __slots__ = []
-
-    def __len__(self):
-        return len(self.delta_ids) if self.delta_ids else 0
-
-
 # this inherits from EventsWorkerStore because it calls self.get_events
 class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
     """The parts of StateGroupStore that can be called from workers."""
diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py
index 9488fd5094..b0642ca69f 100644
--- a/synapse/storage/databases/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@@ -36,9 +36,9 @@ what sort order was used:
 """
 import abc
 import logging
-from collections import namedtuple
 from typing import TYPE_CHECKING, Collection, Dict, List, Optional, Set, Tuple
 
+import attr
 from frozendict import frozendict
 
 from twisted.internet import defer
@@ -74,9 +74,11 @@ _TOPOLOGICAL_TOKEN = "topological"
 
 
 # Used as return values for pagination APIs
-_EventDictReturn = namedtuple(
-    "_EventDictReturn", ("event_id", "topological_ordering", "stream_ordering")
-)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class _EventDictReturn:
+    event_id: str
+    topological_ordering: Optional[int]
+    stream_ordering: int
 
 
 def generate_pagination_where_clause(
@@ -825,7 +827,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
         for event, row in zip(events, rows):
             stream = row.stream_ordering
             if topo_order and row.topological_ordering:
-                topo = row.topological_ordering
+                topo: Optional[int] = row.topological_ordering
             else:
                 topo = None
             internal = event.internal_metadata
diff --git a/synapse/types.py b/synapse/types.py
index b06979e8e8..42aeaf6270 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -15,7 +15,6 @@
 import abc
 import re
 import string
-from collections import namedtuple
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -227,8 +226,7 @@ class DomainSpecificString(metaclass=abc.ABCMeta):
     localpart = attr.ib(type=str)
     domain = attr.ib(type=str)
 
-    # Because this class is a namedtuple of strings and booleans, it is deeply
-    # immutable.
+    # Because this is a frozen class, it is deeply immutable.
     def __copy__(self):
         return self
 
@@ -708,16 +706,18 @@ class PersistedEventPosition:
         return RoomStreamToken(None, self.stream)
 
 
-class ThirdPartyInstanceID(
-    namedtuple("ThirdPartyInstanceID", ("appservice_id", "network_id"))
-):
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class ThirdPartyInstanceID:
+    appservice_id: Optional[str]
+    network_id: Optional[str]
+
     # Deny iteration because it will bite you if you try to create a singleton
     # set by:
     #    users = set(user)
     def __iter__(self):
         raise ValueError("Attempted to iterate a %s" % (type(self).__name__,))
 
-    # Because this class is a namedtuple of strings, it is deeply immutable.
+    # Because this class is a frozen class, it is deeply immutable.
     def __copy__(self):
         return self
 
@@ -725,22 +725,18 @@ class ThirdPartyInstanceID(
         return self
 
     @classmethod
-    def from_string(cls, s):
+    def from_string(cls, s: str) -> "ThirdPartyInstanceID":
         bits = s.split("|", 2)
         if len(bits) != 2:
             raise SynapseError(400, "Invalid ID %r" % (s,))
 
         return cls(appservice_id=bits[0], network_id=bits[1])
 
-    def to_string(self):
+    def to_string(self) -> str:
         return "%s|%s" % (self.appservice_id, self.network_id)
 
     __str__ = to_string
 
-    @classmethod
-    def create(cls, appservice_id, network_id):
-        return cls(appservice_id=appservice_id, network_id=network_id)
-
 
 @attr.s(slots=True)
 class ReadReceipt: