Strange behavior with only one sequence flow with condition

I am having a simple workflow with a condition on a sequence flow

The condition is
= list contains(exit_gateways_fo_b1da4c3c_3764_4485_a1e4_878d0a8685b5, "Found")
When i start a process instance with an empty list in the variable exit_gateways_fo_b1da4c3c_3764_4485_a1e4_878d0a8685b5 the flow succeeded to the end. That is not the behavior i accepted, because the condition was not true?

If i create a new process with two sequence flows and different conditions

Condition 1 = list contains(exit_gateways_fo_b1da4c3c_3764_4485_a1e4_878d0a8685b5, "Found") for found and condition 2 = list contains(exit_gateways_fo_b1da4c3c_3764_4485_a1e4_878d0a8685b5, "NotFound") for not found and i start a new instance on this process, it will give me an error “Expected at least one condition to evaluate to true, or to have a default flow”
This behavior i can understand.

But why will i not get such an error on the first case, where also no condition evaluates to true and we don’t have a default flow?

Hi @Vanguard :wave:

You’ve discovered a bug! :tada:

The BPMN spec is quite clear about the expected behavior:

A default path can optionally be identified, to be taken in the event that none of the conditional Expressions evaluate to true. If a default path is not specified and the Process is executed such that none of the conditional Expressions evaluates to true, a runtime exception occurs. - 10.6.3 Inclusive Gateway

For C8, such a runtime exception is represented by an incident at the inclusive gateway exactly what you saw when using an inclusive gateway with two conditions. The behavior with a single outgoing sequence flow with a condition is incorrect.

I’ll open a bug for it. Thanks for reporting! :bowing_man:


Hi @korthout

just a question to this problem. Can you send me the link to this bug, so that i can watch its status?

Thank you

@Vanguard Looks like it’s already resolved, and the fix is about to be backported to 8.2 and 8.1:

Thanks to @lzgabel and @nicpuppa :heart:

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