[FLINK-20521] Null result values are being swallowed by RPC system

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.11.2, 1.12.0
• Fix Version/s: 1.12.1, 1.13.0
• Component/s: Runtime / Coordination
• Labels: pull-request-available
• Assignee: Till Rohrmann
• Reporter: Till Rohrmann
• Created: 07/Dec/20 13:55
• Updated: 14/Dec/20 12:35
• Resolved: 14/Dec/20 12:35

Description

If an RPC method returns a null value, then it seems that the request future won't get completed as reported in FLINK-17921.

We should either not allow to return null values as responses or make sure that a null value is properly transmitted to the caller.

Issue Links

• is related to: FLINK-17921 RpcGlobalAggregateManager#updateGlobalAggregate would cause unexpected akka.timeout
• links to: GitHub Pull Request #14359