Fix race which caused deleted devices to reappear (#6514)

Stop the `update_client_ips` background job from recreating deleted devices.

3 files changed, 35 insertions, 23 deletions

diff --git a/changelog.d/6514.bugfix b/changelog.d/6514.bugfix
new file mode 100644
index 0000000000..6dc1985c24
--- /dev/null
+++ b/changelog.d/6514.bugfix
@@ -0,0 +1 @@
+Fix race which occasionally caused deleted devices to reappear.
diff --git a/synapse/storage/data_stores/main/client_ips.py b/synapse/storage/data_stores/main/client_ips.py
index 320c5b0f07..add3037b69 100644
--- a/synapse/storage/data_stores/main/client_ips.py
+++ b/synapse/storage/data_stores/main/client_ips.py
@@ -451,16 +451,18 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
                 # Technically an access token might not be associated with
                 # a device so we need to check.
                 if device_id:
-                    self.db.simple_upsert_txn(
+                    # this is always an update rather than an upsert: the row should
+                    # already exist, and if it doesn't, that may be because it has been
+                    # deleted, and we don't want to re-create it.
+                    self.db.simple_update_txn(
                         txn,
                         table="devices",
                         keyvalues={"user_id": user_id, "device_id": device_id},
-                        values={
+                        updatevalues={
                             "user_agent": user_agent,
                             "last_seen": last_seen,
                             "ip": ip,
                         },
-                        lock=False,
                     )
             except Exception as e:
                 # Failed to upsert, log and continue
diff --git a/tests/storage/test_client_ips.py b/tests/storage/test_client_ips.py
index fc279340d4..bf674dd184 100644
--- a/tests/storage/test_client_ips.py
+++ b/tests/storage/test_client_ips.py
@@ -37,9 +37,13 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         self.reactor.advance(12345678)
 
         user_id = "@user:id"
+        device_id = "MY_DEVICE"
+
+        # Insert a user IP
+        self.get_success(self.store.store_device(user_id, device_id, "display name",))
         self.get_success(
             self.store.insert_client_ip(
-                user_id, "access_token", "ip", "user_agent", "device_id"
+                user_id, "access_token", "ip", "user_agent", device_id
             )
         )
 
@@ -47,14 +51,14 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         self.reactor.advance(10)
 
         result = self.get_success(
-            self.store.get_last_client_ip_by_device(user_id, "device_id")
+            self.store.get_last_client_ip_by_device(user_id, device_id)
         )
 
-        r = result[(user_id, "device_id")]
+        r = result[(user_id, device_id)]
         self.assertDictContainsSubset(
             {
                 "user_id": user_id,
-                "device_id": "device_id",
+                "device_id": device_id,
                 "ip": "ip",
                 "user_agent": "user_agent",
                 "last_seen": 12345678000,
@@ -209,14 +213,16 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
                 self.store.db.updates.do_next_background_update(100), by=0.1
             )
 
-        # Insert a user IP
         user_id = "@user:id"
+        device_id = "MY_DEVICE"
+
+        # Insert a user IP
+        self.get_success(self.store.store_device(user_id, device_id, "display name",))
         self.get_success(
             self.store.insert_client_ip(
-                user_id, "access_token", "ip", "user_agent", "device_id"
+                user_id, "access_token", "ip", "user_agent", device_id
             )
         )
-
         # Force persisting to disk
         self.reactor.advance(200)
 
@@ -224,7 +230,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         self.get_success(
             self.store.db.simple_update(
                 table="devices",
-                keyvalues={"user_id": user_id, "device_id": "device_id"},
+                keyvalues={"user_id": user_id, "device_id": device_id},
                 updatevalues={"last_seen": None, "ip": None, "user_agent": None},
                 desc="test_devices_last_seen_bg_update",
             )
@@ -232,14 +238,14 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # We should now get nulls when querying
         result = self.get_success(
-            self.store.get_last_client_ip_by_device(user_id, "device_id")
+            self.store.get_last_client_ip_by_device(user_id, device_id)
         )
 
-        r = result[(user_id, "device_id")]
+        r = result[(user_id, device_id)]
         self.assertDictContainsSubset(
             {
                 "user_id": user_id,
-                "device_id": "device_id",
+                "device_id": device_id,
                 "ip": None,
                 "user_agent": None,
                 "last_seen": None,
@@ -272,14 +278,14 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # We should now get the correct result again
         result = self.get_success(
-            self.store.get_last_client_ip_by_device(user_id, "device_id")
+            self.store.get_last_client_ip_by_device(user_id, device_id)
         )
 
-        r = result[(user_id, "device_id")]
+        r = result[(user_id, device_id)]
         self.assertDictContainsSubset(
             {
                 "user_id": user_id,
-                "device_id": "device_id",
+                "device_id": device_id,
                 "ip": "ip",
                 "user_agent": "user_agent",
                 "last_seen": 0,
@@ -296,11 +302,14 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
                 self.store.db.updates.do_next_background_update(100), by=0.1
             )
 
-        # Insert a user IP
         user_id = "@user:id"
+        device_id = "MY_DEVICE"
+
+        # Insert a user IP
+        self.get_success(self.store.store_device(user_id, device_id, "display name",))
         self.get_success(
             self.store.insert_client_ip(
-                user_id, "access_token", "ip", "user_agent", "device_id"
+                user_id, "access_token", "ip", "user_agent", device_id
             )
         )
 
@@ -324,7 +333,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
                     "access_token": "access_token",
                     "ip": "ip",
                     "user_agent": "user_agent",
-                    "device_id": "device_id",
+                    "device_id": device_id,
                     "last_seen": 0,
                 }
             ],
@@ -347,14 +356,14 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # But we should still get the correct values for the device
         result = self.get_success(
-            self.store.get_last_client_ip_by_device(user_id, "device_id")
+            self.store.get_last_client_ip_by_device(user_id, device_id)
         )
 
-        r = result[(user_id, "device_id")]
+        r = result[(user_id, device_id)]
         self.assertDictContainsSubset(
             {
                 "user_id": user_id,
-                "device_id": "device_id",
+                "device_id": device_id,
                 "ip": "ip",
                 "user_agent": "user_agent",
                 "last_seen": 0,