Flowable task complete issue - UserTask should not be signalled before complete

Flowable Engine
1

Hi,

We are facing below issue details:-

Prerequisite:-
We are using flowable version 6.6.0 as a dependency in spring boot application.

Problem statement:-
We are getting a issue “UserTask should not be signalled before complete" while completing a specific stage.
We have a BPM flow refer below flow diagram just for reference.

bpm
bpm1535×475 9.18 KB

in which sometimes while completing a “E” stage which is after few parallel stages(“B”, “C”), we are facing an issue “UserTask should not be signalled before complete” in BPM logs

java.lang.Exception: UserTask should not be signalled before complete
       at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
       at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
       at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
       at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:366)
       at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
       at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
       at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
       at sun.reflect.GeneratedMethodAccessor777.invoke(Unknown Source)
       at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
       at java.lang.reflect.Method.invoke(Method.java:498)

Temporary Solution:-
We have analysed the issue and found a temporary solution that in “ACT_RU_TASK” table we get multiple records for that task.
SELECT * FROM ACT_RU_TASK art WHERE PROC_INST_ID_ =‘PROCESS_INSTANCE_ID’
We were able to complete the stage “E” after removing those multiple records and keeping a single record in “ACT_RU_TASK” table.

We are looking after the root cause of this problem and need a permanent solution.

2

That particular exception is thrown here: https://github.com/flowable/flowable-engine/blob/main/modules/flowable-engine/src/main/java/org/flowable/engine/impl/bpmn/behavior/UserTaskActivityBehavior.java#L322

and it happens when trying to complete a task, when it’s aready been completed during the same transaction. Are you deleting the process instances potentially beforehand or simultaneously?

Note sure what this means, can you clarify?

3

Hi,

We are not deleting the process instances potentially refer below code that we are using for completing task.

taskService.complete(TASK_ID,VARIABLES)

We found that there were two records in “ACT_RU_TASK” table when we got this issue.

So after deleting previous records we are able to complete task.