Semantics of nextStep in final step of workflow

[kezike]

In the final step of a workflow step, should nextStep be the same as the current stepName or should it be undefined? I’ve seen examples where the former is considered a cycle and the latter is considered correct, but this should be clarified in the specification. If we accept the latter approach (undefined value of nextStep in final step), we would need to make this an optional value in the specification text and the OpenAPI definition.

[dlongley]

Yeah, it should be considered a cycle (and, therefore, an error), i.e., no step should have as its next step the same step. We should also suggest a maximum total number of steps to prevent longer cycles (there are implementations today that have their own built-in maximums, but we should at least mention this and suggest maximum number in the spec).

I agree that we should define nextStep as optional (or require it to be null to signal the final step, TBD).

[msporny]

The group discussed this on the 2025-02-18 telecon. @dlongley noted that a PR needs to be raised that nextStep should never refer to the current step. We should suggest what the maxmimum number of steps but not put a hard limit. If nextStep is not present, the current step is the last step.