properly puncuate newsfragment

changelog.d/15849.misc

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+Add check constraint to current_state_delta_stream (#15849).

synapse/storage/schema/main/delta/78/05_add_constraint_current_state_delta_stream.py

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+# Copyright 2023 The Matrix.org Foundation C.I.C
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  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 synapse.storage.database import LoggingTransaction
+from synapse.storage.engines import BaseDatabaseEngine, Sqlite3Engine
+
+
+def run_create(cur: LoggingTransaction, database_engine: BaseDatabaseEngine) -> None:
+    if isinstance(database_engine, Sqlite3Engine):
+        create_sql = """
+         CREATE TABLE temp_current_state_delta_stream (
+            stream_id bigint NOT NULL,
+            room_id text NOT NULL,
+            type text NOT NULL,
+            state_key text NOT NULL,
+            event_id text,
+            prev_event_id text,
+            instance_name text
+            CHECK (event_id != prev_event_id)
+        )
+        """
+        cur.execute(create_sql)
+
+        copy_sql = """
+            INSERT INTO temp_current_state_delta_stream SELECT * FROM current_state_delta_stream
+        """
+        cur.execute(copy_sql)
+
+        drop_sql = """
+            DROP TABLE current_state_delta_stream
+        """
+        cur.execute(drop_sql)
+
+        alter_sql = """
+            ALTER TABLE temp_current_state_delta_stream RENAME to current_state_delta_stream
+        """
+        cur.execute(alter_sql)
+
+        idx_sql = """
+            CREATE INDEX current_state_delta_stream_idx ON current_state_delta_stream(stream_id)
+        """
+        cur.execute(idx_sql)
+    else:
+        constraint_sql = """
+            ALTER TABLE current_state_delta_stream ADD CONSTRAINT prev_event_id_and_event_id_not_equal
+            CHECK (prev_event_id != event_id)
+        """
+        cur.execute(constraint_sql)