[Bug] api/alerts and api/alert/:id hold previous data for "message" and "Message" field when field value is changed from "some string" to empty string.

[jaimegago]

Bug has been reproduced on v4.2.0, v4.1.2, v4.1.1.

1. Create a new alert with empty message + save dashboard
2. Select view JSON for that new dashboard -> produced output contains "message": ""
3. GET http://grafana/api/alerts -> produced output for the alert contains "message": ""
4. GET http://grafana/api/alerts/:id -> produced output for the alert contains "message": "" and "Message":""
5. Change message field from empty to "foobar" + save dashboard
6. Select view JSON -> produced output contains "message": "foobar"
7. GET http://gragana/api/alerts -> produced output for the alert contains "message": "foobar"
8. GET http://grafana/api/alerts/:id -> produced output for the alert contains "message": "foobar" and "Message":"foobar"
9. Change message field from "foobar" back to empty + save dashboard
10. Select view JSON for that new dashboard -> produced output contains "message": ""
11. GET http://grafana/api/alerts -> produced output for the alert contains "message": "foobar" which is the bug as there is no more "foobar" value for the message field.
12. GET http://grafana/api/alerts/:id -> produced output for the alert contains "message": "" and "Message":"foobar" which is also a bug

[torkelo]

thanks for reporting this!