Fix deletion for Dehydrated Devices (#16046)

2 files changed, 26 insertions, 4 deletions

diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index f3a713f5fa..b7bf70a72d 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -722,6 +722,22 @@ class DeviceHandler(DeviceWorkerHandler):
 
         return {"success": True}
 
+    async def delete_dehydrated_device(self, user_id: str, device_id: str) -> None:
+        """
+        Delete a stored dehydrated device.
+
+        Args:
+            user_id: the user_id to delete the device from
+            device_id: id of the dehydrated device to delete
+        """
+        success = await self.store.remove_dehydrated_device(user_id, device_id)
+
+        if not success:
+            raise errors.NotFoundError()
+
+        await self.delete_devices(user_id, [device_id])
+        await self.store.delete_e2e_keys_by_device(user_id=user_id, device_id=device_id)
+
     @wrap_as_background_process("_handle_new_device_update_async")
     async def _handle_new_device_update_async(self) -> None:
         """Called when we have a new local device list update that we need to
diff --git a/synapse/rest/client/devices.py b/synapse/rest/client/devices.py
index 690d2ec406..dd3f7fd666 100644
--- a/synapse/rest/client/devices.py
+++ b/synapse/rest/client/devices.py
@@ -513,10 +513,8 @@ class DehydratedDeviceV2Servlet(RestServlet):
         if dehydrated_device is not None:
             (device_id, device_data) = dehydrated_device
 
-            result = await self.device_handler.rehydrate_device(
-                requester.user.to_string(),
-                self.auth.get_access_token_from_request(request),
-                device_id,
+            await self.device_handler.delete_dehydrated_device(
+                requester.user.to_string(), device_id
             )
 
             result = {"device_id": device_id}
@@ -538,6 +536,14 @@ class DehydratedDeviceV2Servlet(RestServlet):
         requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
+        old_dehydrated_device = await self.device_handler.get_dehydrated_device(user_id)
+
+        # if an old device exists, delete it before creating a new one
+        if old_dehydrated_device:
+            await self.device_handler.delete_dehydrated_device(
+                user_id, old_dehydrated_device[0]
+            )
+
         device_info = submission.dict()
         if "device_keys" not in device_info.keys():
             raise SynapseError(