GWphua opened a new pull request, #19425: URL: https://github.com/apache/druid/pull/19425
### Description This PR fixes a rolling-upgrade compatibility issue when Brokers are upgraded before Overlords. In my case, I faced the following issue when upgrading from v27 -> v37. Newer Brokers expect `SupervisorStatus` responses to include the `dataSource` field. Older Overlords do not include that field, so a newer Broker can deserialize an old Overlord response with a null datasource and later hit a `NullPointerException`. This PR preserves compatibility by falling back to the supervisor `id` when `dataSource` is absent. This matches the old response shape where the supervisor id is the datasource identifier for this status object. A regression test was added for deserializing an old Overlord response without `dataSource`. #### Release note Fixes a rolling-upgrade issue where upgrading Brokers before Overlords could cause a `NullPointerException` while reading supervisor status responses from older Overlords. <hr> <!-- Check the items by putting "x" in the brackets for the done things. Not all of these items apply to every PR. Remove the items which are not done or not relevant to the PR. None of the items from the checklist below are strictly necessary, but it would be very helpful if you at least self-review the PR. --> This PR has: - [x] been self-reviewed. - [x] a release note entry in the PR description. - [ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader. - [ ] added unit tests or modified existing tests to cover new code paths, ensuring the threshold for [code coverage](https://github.com/apache/druid/blob/master/dev/code-review/code-coverage.md) is met. - [ ] added integration tests. - [ ] been tested in a test Druid cluster. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
