I was looking through the activity error retry states. Will appreciate some clarity on
RETRY_STATE_IN_PROGRESS . When should we expect the state?
IIUC, control only goes to workflow in case, activity processing has terminated.
You should expect a this activity to occur once the RetryState has been activated due to the code not working properly. The idea is that if workflow code is changed without versioning the workflow progress is blocked without failing workflow. So, if the broken code is rolled back workflow can continue execution without a problem. Failing workflow might be catastrophic. Imagine a few million multi-month workflows failing in production due to a single bad deployment.
Control will automatically go to activity unless, you use a different enumeration such as Abandon, Try_cancel, or Wait_cancellation_completed.