handle automatic creation of transtions in barrier state

[franzlst]

Barrier states can be created in several way:

1. empty
2. with a states list passed to the constructor
3. with a states and transition list passed to the constructor

Cases 1. and 2. are straight forward.

In case 3. the transitions have to be handled carefully:

• transitions are normally automatically created, this must not be done in this case as some transitions could be duplicated
• only using the passed transition list can also be wrong as it could not be complete

Now there are two possible solutions:

1. we let all transitions create automatically while "add_state" function is called + add only those transitions of the passed transition list which originate from the decider state; optional consistency check of other transitions in the passed transition list => warning prints intended for developer
2. we let all transitions create automatically while "add_state" function is called + add only those transitions of the passed transition list which do not target the decider state; optional consistency check is not necessary as invalid transitions lead to exceptions anyway
3. add states without transitions + add all transitions of passed transition list + fill up missing transitions

@Rbelder and @sebastian-brunner vote for option 2.

Discussion is welcome.

Originally created by @sebastian-brunner ([email protected]) at 2018-02-19 15:11:13+00:00 (moved from RMC internal repository)