Combine AbstractStreamIdTracker and AbstractStreamIdGenerator. (#15192)

AbstractStreamIdTracker (now) has only a single sub-class: AbstractStreamIdGenerator,
combine them to simplify some code and remove any direct references to
AbstractStreamIdTracker.

7 files changed, 15 insertions, 27 deletions

diff --git a/changelog.d/15192.misc b/changelog.d/15192.misc
new file mode 100644
index 0000000000..1076686875
--- /dev/null
+++ b/changelog.d/15192.misc
@@ -0,0 +1 @@
+Combine `AbstractStreamIdTracker` and `AbstractStreamIdGenerator`.
diff --git a/synapse/storage/databases/main/devices.py b/synapse/storage/databases/main/devices.py
index 0dd15f16ff..5503621ad6 100644
--- a/synapse/storage/databases/main/devices.py
+++ b/synapse/storage/databases/main/devices.py
@@ -52,7 +52,6 @@ from synapse.storage.databases.main.roommember import RoomMemberWorkerStore
 from synapse.storage.types import Cursor
 from synapse.storage.util.id_generators import (
     AbstractStreamIdGenerator,
-    AbstractStreamIdTracker,
     StreamIdGenerator,
 )
 from synapse.types import JsonDict, StrCollection, get_verify_key_from_cross_signing_key
@@ -91,7 +90,7 @@ class DeviceWorkerStore(RoomMemberWorkerStore, EndToEndKeyWorkerStore):
 
         # In the worker store this is an ID tracker which we overwrite in the non-worker
         # class below that is used on the main process.
-        self._device_list_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
+        self._device_list_id_gen = StreamIdGenerator(
             db_conn,
             hs.get_replication_notifier(),
             "device_lists_stream",
@@ -712,9 +711,7 @@ class DeviceWorkerStore(RoomMemberWorkerStore, EndToEndKeyWorkerStore):
             The new stream ID.
         """
 
-        # TODO: this looks like it's _writing_. Should this be on DeviceStore rather
-        #  than DeviceWorkerStore?
-        async with self._device_list_id_gen.get_next() as stream_id:  # type: ignore[attr-defined]
+        async with self._device_list_id_gen.get_next() as stream_id:
             await self.db_pool.runInteraction(
                 "add_user_sig_change_to_streams",
                 self._add_user_signature_change_txn,
diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py
index b7e7498125..20b7a68362 100644
--- a/synapse/storage/databases/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -72,7 +72,6 @@ from synapse.storage.engines import PostgresEngine
 from synapse.storage.types import Cursor
 from synapse.storage.util.id_generators import (
     AbstractStreamIdGenerator,
-    AbstractStreamIdTracker,
     MultiWriterIdGenerator,
     StreamIdGenerator,
 )
@@ -187,8 +186,8 @@ class EventsWorkerStore(SQLBaseStore):
     ):
         super().__init__(database, db_conn, hs)
 
-        self._stream_id_gen: AbstractStreamIdTracker
-        self._backfill_id_gen: AbstractStreamIdTracker
+        self._stream_id_gen: AbstractStreamIdGenerator
+        self._backfill_id_gen: AbstractStreamIdGenerator
         if isinstance(database.engine, PostgresEngine):
             # If we're using Postgres than we can use `MultiWriterIdGenerator`
             # regardless of whether this process writes to the streams or not.
diff --git a/synapse/storage/databases/main/push_rule.py b/synapse/storage/databases/main/push_rule.py
index 9b2bbe060d..9f862f00c1 100644
--- a/synapse/storage/databases/main/push_rule.py
+++ b/synapse/storage/databases/main/push_rule.py
@@ -46,7 +46,6 @@ from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.storage.push_rule import InconsistentRuleException, RuleNotFoundException
 from synapse.storage.util.id_generators import (
     AbstractStreamIdGenerator,
-    AbstractStreamIdTracker,
     IdGenerator,
     StreamIdGenerator,
 )
@@ -118,7 +117,7 @@ class PushRulesWorkerStore(
 
         # In the worker store this is an ID tracker which we overwrite in the non-worker
         # class below that is used on the main process.
-        self._push_rules_stream_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
+        self._push_rules_stream_id_gen = StreamIdGenerator(
             db_conn,
             hs.get_replication_notifier(),
             "push_rules_stream",
diff --git a/synapse/storage/databases/main/pusher.py b/synapse/storage/databases/main/pusher.py
index fddbc07afa..9a24f7a655 100644
--- a/synapse/storage/databases/main/pusher.py
+++ b/synapse/storage/databases/main/pusher.py
@@ -36,7 +36,6 @@ from synapse.storage.database import (
 )
 from synapse.storage.util.id_generators import (
     AbstractStreamIdGenerator,
-    AbstractStreamIdTracker,
     StreamIdGenerator,
 )
 from synapse.types import JsonDict
@@ -60,7 +59,7 @@ class PusherWorkerStore(SQLBaseStore):
 
         # In the worker store this is an ID tracker which we overwrite in the non-worker
         # class below that is used on the main process.
-        self._pushers_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
+        self._pushers_id_gen = StreamIdGenerator(
             db_conn,
             hs.get_replication_notifier(),
             "pushers",
diff --git a/synapse/storage/databases/main/receipts.py b/synapse/storage/databases/main/receipts.py
index 92a82240ab..074942b167 100644
--- a/synapse/storage/databases/main/receipts.py
+++ b/synapse/storage/databases/main/receipts.py
@@ -39,7 +39,7 @@ from synapse.storage.database import (
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.engines._base import IsolationLevel
 from synapse.storage.util.id_generators import (
-    AbstractStreamIdTracker,
+    AbstractStreamIdGenerator,
     MultiWriterIdGenerator,
     StreamIdGenerator,
 )
@@ -65,7 +65,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
         # In the worker store this is an ID tracker which we overwrite in the non-worker
         # class below that is used on the main process.
-        self._receipts_id_gen: AbstractStreamIdTracker
+        self._receipts_id_gen: AbstractStreamIdGenerator
 
         if isinstance(database.engine, PostgresEngine):
             self._can_write_to_receipts = (
@@ -768,7 +768,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
                 "insert_receipt_conv", self._graph_to_linear, room_id, event_ids
             )
 
-        async with self._receipts_id_gen.get_next() as stream_id:  # type: ignore[attr-defined]
+        async with self._receipts_id_gen.get_next() as stream_id:
             event_ts = await self.db_pool.runInteraction(
                 "insert_linearized_receipt",
                 self._insert_linearized_receipt_txn,
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index 334d3d718b..d2c874b9a8 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -93,8 +93,11 @@ def _load_current_id(
     return res
 
 
-class AbstractStreamIdTracker(metaclass=abc.ABCMeta):
-    """Tracks the "current" stream ID of a stream that may have multiple writers.
+class AbstractStreamIdGenerator(metaclass=abc.ABCMeta):
+    """Generates or tracks stream IDs for a stream that may have multiple writers.
+
+    Each stream ID represents a write transaction, whose completion is tracked
+    so that the "current" stream ID of the stream can be determined.
 
     Stream IDs are monotonically increasing or decreasing integers representing write
     transactions. The "current" stream ID is the stream ID such that all transactions
@@ -130,16 +133,6 @@ class AbstractStreamIdTracker(metaclass=abc.ABCMeta):
         """
         raise NotImplementedError()
 
-
-class AbstractStreamIdGenerator(AbstractStreamIdTracker):
-    """Generates stream IDs for a stream that may have multiple writers.
-
-    Each stream ID represents a write transaction, whose completion is tracked
-    so that the "current" stream ID of the stream can be determined.
-
-    See `AbstractStreamIdTracker` for more details.
-    """
-
     @abc.abstractmethod
     def get_next(self) -> AsyncContextManager[int]:
         """