Ensure pushers are deleted for deactivated accounts (#9285)

changelog.d/9285.bugfix

@@ -0,0 +1 @@
+Fix a bug where users' pushers were not all deleted when they deactivated their account.

synapse/handlers/deactivate_account.py

@@ -120,6 +120,11 @@ async def deactivate_account(
 
         await self.store.user_set_password_hash(user_id, None)
 
+        # Most of the pushers will have been deleted when we logged out the
+        # associated devices above, but we still need to delete pushers not
+        # associated with devices, e.g. email pushers.
+        await self.store.delete_all_pushers_for_user(user_id)
+
         # Add the user to a table of users pending deactivation (ie.
         # removal from all the rooms they're a member of)
         await self.store.add_user_pending_deactivation(user_id)

synapse/storage/databases/main/pusher.py

@@ -373,3 +373,46 @@ def delete_pusher_txn(txn, stream_id):
             await self.db_pool.runInteraction(
                 "delete_pusher", delete_pusher_txn, stream_id
             )
+
+    async def delete_all_pushers_for_user(self, user_id: str) -> None:
+        """Delete all pushers associated with an account."""
+
+        # We want to generate a row in `deleted_pushers` for each pusher we're
+        # deleting, so we fetch the list now so we can generate the appropriate
+        # number of stream IDs.
+        #
+        # Note: technically there could be a race here between adding/deleting
+        # pushers, but a) the worst case if we don't stop a pusher until the
+        # next restart and b) this is only called when we're deactivating an
+        # account.
+        pushers = list(await self.get_pushers_by_user_id(user_id))
+
+        def delete_pushers_txn(txn, stream_ids):
+            self._invalidate_cache_and_stream(  # type: ignore
+                txn, self.get_if_user_has_pusher, (user_id,)
+            )
+
+            self.db_pool.simple_delete_txn(
+                txn,
+                table="pushers",
+                keyvalues={"user_name": user_id},
+            )
+
+            self.db_pool.simple_insert_many_txn(
+                txn,
+                table="deleted_pushers",
+                values=[
+                    {
+                        "stream_id": stream_id,
+                        "app_id": pusher.app_id,
+                        "pushkey": pusher.pushkey,
+                        "user_id": user_id,
+                    }
+                    for stream_id, pusher in zip(stream_ids, pushers)
+                ],
+            )
+
+        async with self._pushers_id_gen.get_next_mult(len(pushers)) as stream_ids:
+            await self.db_pool.runInteraction(
+                "delete_all_pushers_for_user", delete_pushers_txn, stream_ids
+            )

synapse/storage/databases/main/schema/delta/59/08delete_pushers_for_deactivated_accounts.sql

@@ -0,0 +1,21 @@
+/* Copyright 2021 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.
+ */
+
+
+-- We may not have deleted all pushers for deactivated accounts. Do so now.
+--
+-- Note: We don't bother updating the `deleted_pushers` table as it's just use
+-- to stop pushers on workers, and that will happen when they get next restarted.
+DELETE FROM pushers WHERE user_name IN (SELECT name FROM users WHERE deactivated = 1);