flowable/flowable-engine · error · FlowableIllegalArgumentException

Illegal value for delegationState

Error message

Illegal value for delegationState: ${delegationState}

What it means

TaskBaseResource.getDelegationState converts a query parameter string into the DelegationState enum, accepting only the lowercase names 'resolved' and 'pending'. Any other value cannot be mapped, so FlowableIllegalArgumentException is thrown with the offending value.

Solutions

  1. Send delegationState=pending or delegationState=resolved (lowercase).
  2. Omit the parameter entirely when you do not want to filter on delegation state.
  3. Whitelist/normalize the value in the client before building the query.
  4. Catch the 400 response and correct the parameter.

Example fix

// before
GET /runtime/tasks?delegationState=PENDING
// after
GET /runtime/tasks?delegationState=pending
Defensive patterns

Strategy: validation

Validate before calling

if (delegationState != null && !['pending','resolved'].includes(delegationState)) throw new Error('delegationState must be pending or resolved');

Type guard

const isDelegationState = (s) => s === 'pending' || s === 'resolved';

Try / catch

try { await queryTasks({delegationState}); } catch (e) { if (e.status === 400 && /delegationState/.test(e.message)) { delete params.delegationState; } else { throw e; } }

Prevention

When it happens

Trigger: Task query REST call with delegationState=<value> where value is not 'pending' or 'resolved' (e.g. 'PENDING' uppercase, 'delegated', an empty string, or 'involved').

Common situations: Passing the raw enum name in uppercase; UI dropdowns listing states not valid for task queries; copied values from process-instance APIs that support extra states.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/8fda57d25ebc3a94. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-rest/src/main/java/org/flowable/cmmn/rest/service/api/runtime/task/TaskBaseResource.java:82

    @Autowired
    protected CmmnTaskService taskService;

    @Autowired
    protected CmmnHistoryService historyService;

    @Autowired(required=false)
    protected CmmnRestApiInterceptor restApiInterceptor;

    protected DelegationState getDelegationState(String delegationState) {
        DelegationState state = null;
        if (delegationState != null) {
            if (DelegationState.RESOLVED.name().toLowerCase().equals(delegationState)) {
                return DelegationState.RESOLVED;
            } else if (DelegationState.PENDING.name().toLowerCase().equals(delegationState)) {
                return DelegationState.PENDING;
            } else {
                throw new FlowableIllegalArgumentException("Illegal value for delegationState: " + delegationState);
            }
        }
        return state;
    }

    /**
     * Populate the task based on the values that are present in the given {@link TaskRequest}.
     */
    protected void populateTaskFromRequest(Task task, TaskRequest taskRequest) {
        if (taskRequest.isNameSet()) {
            task.setName(taskRequest.getName());
        }
        if (taskRequest.isAssigneeSet()) {
            task.setAssignee(taskRequest.getAssignee());
        }
        if (taskRequest.isDescriptionSet()) {
            task.setDescription(taskRequest.getDescription());
        }

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