[FEAT] CasePathResolver: handle "backward lonely edge" with exclusive gateways

[tbouffard]

DISCLAIMER: this issue describes path computation for a single instance/case only. So the implementation will go to the CasePathResolver class as it differs from PathResolver which is a generic implementation that both deals with single instance or all instances of a process.

Is your feature request related to a problem? Please describe.

Sometimes, there is a loop with a gateway with a branch without element (ege only) going back to another exclusive gateway (called "backward" branch here).
In this case, it is not possible to detect if this lonely edge branch is part of the path. We would need a frequency information to be able to decide.
We can only assume that this edge is a candidate (#24).

Note: this use case doesn't apply to parallel gateways (we don't want to support non conformant model)

flowchart LR
    task --> gatewaySplit{X}
    gatewaySplit --> task1 --> gatewayMerge{X}
    gatewaySplit --> task2 --> gatewayMerge
    -->   gatewaySplit
    gatewayMerge --> anotherTask

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Describe the solution you'd like

Handle the case.
Provide an option to know if this is a detection for "single instance" or "multiple instances"

If the "backward branch" contains an elements provided in the inputs, all edges of the branch should be detected as part of the path (as already supported prior implementing this use case)

flowchart LR
    task --> gatewaySplit{X}
    gatewaySplit --> task1 --> gatewayMerge{X}
    gatewaySplit --> task2 --> gatewayMerge
    -->  task3 -->   gatewaySplit
    gatewayMerge --> anotherTask

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Should also work when the backward branch comes from a boundary event (part of the input) and goes to an exclusive gateway.

Questions

• Do we introduce an option as part of [FEAT] CasePathResolver: let provide options to tune the path computation #23 to enable the processing of such an use case?