Error on Multiinstance with 0 iterations

[lucas_matw]

Hi!

I'm having some problems with multiinstace sub-process/task when it collection is empty and "isSequential" is false.

I have isolated the case with this:

  <process id="myProcess" name="My process" isExecutable="true">
    <startEvent id="startevent1" name="Start"></startEvent>
    <userTask id="userTask" name="userTask" activiti:assignee="user"></userTask>
    <endEvent id="endevent1" name="End"></endEvent>
    <sequenceFlow id="flow5" sourceRef="userTask" targetRef="endevent1"></sequenceFlow>
    <userTask id="multiInstanceTask" name="multiInstanceTask">
      <multiInstanceLoopCharacteristics isSequential="false">
        <loopCardinality>0</loopCardinality>
      </multiInstanceLoopCharacteristics>
    </userTask>
    <sequenceFlow id="flow6" sourceRef="startevent1" targetRef="multiInstanceTask"></sequenceFlow>
    <sequenceFlow id="flow7" sourceRef="multiInstanceTask" targetRef="userTask"></sequenceFlow>
  </process>
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It throws this exception when you try to start a process:

org.activiti.engine.impl.pvm.PvmException: already taking a transition
   at org.activiti.engine.impl.persistence.entity.ExecutionEntity.take(ExecutionEntity.java:445)
   at org.activiti.engine.impl.persistence.entity.ExecutionEntity.takeAll(ExecutionEntity.java:549)
   at org.activiti.engine.impl.bpmn.behavior.ParallelMultiInstanceBehavior.leave(ParallelMultiInstanceBehavior.java:151)
…
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But It works fine when "isSequential" is true, why?

Thanks!

[trademak]

Hi,

Thanks for reporting this. I think it's a bug, I'll look into it tomorrow and come back with a final answer after doing some debugging.

Best regards,

[lucas_matw]

Hello trademak,

Just to add more information. When I came to this error was on a multiiinstance sub-process with 0 iterations.
There is an important difference depending on which Activiti version is used,
5.17 = throws NullPointerException
5.18 = no exceptions, but the new Task is not created

Thanks for your answer.

[trademak]

Thanks, I've made some fixes that should resolve the issue.
Could you check against the current Github master if it resolves your issue?

Thanks,

[lucas_matw]

Hi!

I've just ran some tests with that version and it seems to work well

Thanks!

Lucas