Comment by lorendsr

At some point, if you can't automatically fix something, you have to stop and report to a human for manual intervention/repair. While a saga doesn't guarantee that you avoid manual repair, it significantly reduces the need for it. If each of these has a 1% chance of non-retryable failure:

Step1

Step2

Step1Undo

then this has a 1% chance of needing manual repair (it's okay if step1 fails, but if step1 succeeds and step2 fails, we need to repair):

do Step1

do Step2

and this has a .01% chance (we only repair if Step2 and Step1Undo fails, 1% * 1%):

do Step1

try {

  do Step2

} catch {

  do Step1Undo

}