flowable/flowable-engine · error · FlowableIllegalArgumentException

Illegal value for delegationState

Error message

Illegal value for delegationState: {delegationState}

What it means

FlowableIllegalArgumentException thrown when a task query includes a delegationState request parameter whose value is neither 'pending' nor 'resolved' (case-insensitive). Only those two DelegationState values are accepted by this converter.

Solutions

1. Send only 'pending' or 'resolved' (case-insensitive) as delegationState
2. Omit the parameter entirely to get all tasks regardless of delegation state
3. Check the client's enum mapping against Flowable's DelegationState
4. Trim whitespace and remove accidental suffixes from the parameter

Example fix

// before
GET /runtime/tasks?delegationState=delegated
// after
GET /runtime/tasks?delegationState=pending

const VALID = ['pending','resolved'];
if (delegationState != null && !VALID.includes(delegationState.toLowerCase().trim())) throw new Error(`delegationState must be 'pending' or 'resolved', got: ${delegationState}`);

function isDelegationState(v) { return v == null || ['pending','resolved'].includes(String(v).toLowerCase().trim()); }

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

When it happens

Trigger: Task list query GET /runtime/tasks?delegationState=foo (or 'resolve', 'resolved ', uppercase variants are fine — only unknown words fail) where the string doesn't match PENDING or RESOLVED.

Common situations: Clients sending their own enum spellings ('delegated', 'resolve'); an extra null/empty variant the API doesn't support; API-version drift where a client expects more states than Flowable defines.

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

• Invalid action: ''.
• Only 'binary' and 'serializable' are supported as variable…
• Unsupported variable query operation:
• Unsupported variable query operation
• A group or a user is required to create an identity link.

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/08bca5ffa8486a88. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-rest/src/main/java/org/flowable/rest/service/api/runtime/task/TaskBaseResource.java:83

    @Autowired
    protected TaskService taskService;

    @Autowired
    protected HistoryService historyService;
    
    @Autowired(required=false)
    protected BpmnRestApiInterceptor 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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