flowable/flowable-engine · error · FlowableIllegalStateException

Cannot trigger case task plan item instance : reference type

Error message

Cannot trigger case task plan item instance : reference type '${referenceType}' not supported

What it means

After checking referenceId, CaseTaskActivityBehavior.trigger validates that referenceType equals ReferenceTypes.PLAN_ITEM_CHILD_CASE. Any other reference type means this plan item is not backed by a child case, so triggering it as a case task is unsupported and this error is thrown.

Source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/behavior/impl/CaseTaskActivityBehavior.java:172

                    .handleFormFieldsOnSubmit(variableInfo.formInfo, null, null, caseInstanceEntity.getId(), ScopeTypes.CMMN,
                            variablesFromFormSubmission, caseInstanceEntity.getTenantId());
        }

        if (!blocking) {
            CommandContextUtil.getAgenda(commandContext).planCompletePlanItemInstanceOperation(planItemInstanceEntity);
        }
    }

    @Override
    public void trigger(CommandContext commandContext, PlanItemInstanceEntity planItemInstance) {
        if (!PlanItemInstanceState.ACTIVE.equals(planItemInstance.getState())) {
            throw new FlowableIllegalStateException("Can only trigger a plan item that is in the ACTIVE state");
        }
        if (planItemInstance.getReferenceId() == null) {
            throw new FlowableIllegalStateException("Cannot trigger case task plan item instance : no reference id set");
        }
        if (!ReferenceTypes.PLAN_ITEM_CHILD_CASE.equals(planItemInstance.getReferenceType())) {
            throw new FlowableIllegalStateException("Cannot trigger case task plan item instance : reference type '"
                    + planItemInstance.getReferenceType() + "' not supported");
        }

        // load the case instance referenced by this case task plan item to check its current state
        CaseInstanceEntity caseInstance = CommandContextUtil.getCaseInstanceEntityManager(commandContext).findById(planItemInstance.getReferenceId());

        if (caseInstance != null) {
            // Out parameters are handled here only when the case is still active (manual trigger scenario).
            // When the child case completed normally, out parameters are already handled
            // in ChildCaseInstanceStateChangeCallback before the child case gets deleted.
            handleOutParameters(commandContext, planItemInstance);

            if (caseInstance.getState().equals(CaseInstanceState.ACTIVE)) {
                // Triggering the plan item (as opposed to a regular complete of the referenced case) manually terminates the case instance
                CommandContextUtil.getAgenda(commandContext).planManualTerminateCaseInstanceOperation(planItemInstance.getReferenceId());
            }
        }

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Ensure the planItemInstanceId passed to triggerPlanItemInstance belongs to a case task plan item.
2. Check planItemInstance.getReferenceType() equals PLAN_ITEM_CHILD_CASE before triggering.
3. Use the behavior-appropriate completion path for other task types (e.g. process task handled via the child process).
4. Audit runtime tables for corrupted reference_type values if this occurs without user error.

Example fix

// before
runtimeService.triggerPlanItemInstance(id); // plan item is a child-process task
// after
PlanItemInstance pii = runtimeService.createPlanItemInstanceQuery()
    .planItemInstanceId(id).singleResult();
if (ReferenceTypes.PLAN_ITEM_CHILD_CASE.equals(pii.getReferenceType())) {
    runtimeService.triggerPlanItemInstance(id);
}

PlanItemInstance pii = cmmnRuntimeService.createPlanItemInstanceQuery().planItemInstanceId(id).singleResult();
boolean isChildCase = pii != null && ReferenceTypes.PLAN_ITEM_CHILD_CASE.equals(pii.getReferenceType());

try {
    cmmnRuntimeService.triggerPlanItemInstance(id);
} catch (FlowableIllegalStateException e) {
    if (e.getMessage().contains("reference type")) {
        // wrong plan item type passed — route to the correct completion API
    }
}

When it happens

Trigger: Triggering a plan item instance whose referenceType is something other than PLAN_ITEM_CHILD_CASE — e.g. data from a different behavior type was reused, or instance data was migrated/corrupted across task types.

Common situations: Mixing up ids of case task and process task (child process) plan items when calling triggerPlanItemInstance; runtime data migrated from another engine version or another task type; custom behaviors setting their own reference types.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Can only delete a child entity for a plan item with referenc
• Could not start case instance: no case reference defined in
• Can only trigger a plan item that is in the ACTIVE state
• Cannot trigger case task plan item instance : no reference i
• Cannot trigger process task plan item instance : reference t

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/193ae2cf99e9557b. Report an issue: GitHub.