DelayerEndpointSpec doesn't allow to specify custom taskScheduler

[pziobron]

In what version(s) of Spring Integration are you seeing this issue?
6.2.11

Describe the bug
The custom taskScheduler is not configured for delay handler when using DelayerEndpointSpec#taskScheduler() method.
The default taskScheduler is used instead (IntegrationObjectSupport#getTaskScheduler() - taskScheduler is null)

To Reproduce

Use this code snippet:
subscribe(flow -> flow.delay(d -> d.messageGroupId("testDelayer").taskScheduler(myCustomTaskScheduler))).nullChannel();

when the delayer is executed the taskScheduler field is null and the default task scheduler is retrieved (IntegrationObjectSupport#getTaskScheduler())

I need to use this workaround to make it working properly:

DelayHandler handler = newDelayHandler("testDelayer", myCustomTaskScheduler);
subscribe(flow -> flow.handle(handler)).nullChannel();

Expected behavior

It should be possible to configure custom task scheduler using DelayerEndpointSpec#taskScheduler()

[artembilan]

Confirmed.
The ConsumerEndpointSpec does set the provided scheduler, but only into an endpoint for this handler.
I guess we just need to override that method on the DelayerEndpointSpec and set scheduler respectively to the handler as well.

I hope the config you provide is just for issue comment purpose.
Otherwise it does not make sense to delay a message just to discard it afterward...

[pziobron]

Yes, agree, the code snippet doesn't make sense here, in the real code the other handler is processing the message after a delay.
I’ve simplified it too much :)

Should be:

subscribe(flow -> flow.delay(d -> d.messageGroupId("testDelayer").taskScheduler(myCustomTaskScheduler)).handle(otherHandler).nullChannel());