Understanding rollbacks in new chunk-oriented processing model

[marbon87]

Hi,

related to #5210 and a similar problem, i am trying to understand the rollback mechanism in the new chunk-oriented processing model.

In the old / deprecated implementation a skipable exception in the writer triggers a rollback of the transaction and chunk scanning.
In the new implementation no rollback is triggered.

I created a simple example: example.zip

When running the ExampleTest with the old implementation, 3 rollbacks are triggered,
If i change the test to use the new implementation (in lines 55/56) the test is failing because 0 rollbacks are done.

Can someone explain to me why no rollbacks are done? I could not find a detailed documentation of the chunk scanning and rollback mechanism in the spring-batch ref doc.