flowable/flowable-engine · error · FlowableIllegalArgumentException

Incompatible usage: cannot use type '' together with a…

Error message

Incompatible usage: cannot use type '' together with a groupId

What it means

DeleteIdentityLinkCmd.validateParams throws FlowableIllegalArgumentException when type is ASSIGNEE or OWNER but a groupId is also supplied. Assignee/owner links apply to a single user only, so combining them with a group is a contradictory request.

Solutions

1. Pass groupId = null when the type is ASSIGNEE or OWNER.
2. Use a group type (e.g. CANDIDATE) if the link to remove actually targets a group.

Example fix

// before
taskService.deleteTaskIdentityLink(taskId, userId, groupId, IdentityLinkType.ASSIGNEE);
// after
taskService.deleteTaskIdentityLink(taskId, userId, null, IdentityLinkType.ASSIGNEE);

if ((IdentityLinkType.ASSIGNEE.equals(type) || IdentityLinkType.OWNER.equals(type)) && groupId != null) { throw new IllegalArgumentException("groupId not allowed for " + type); }

try { taskService.deleteTaskIdentityLink(taskId, userId, groupId, type); } catch (FlowableIllegalArgumentException e) { log.error("Incompatible link parameters: {}", e.getMessage()); }

When it happens

Trigger: Calling taskService.deleteTaskIdentityLink with type ASSIGNEE or OWNER and a non-null groupId, e.g. generic link-removal code that always passes both userId and groupId.

Common situations: Refactorings that route all identity-link deletions through one generic method and pass all parameters unconditionally; misunderstanding of which link types are group-scoped.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

• caseDefinitionId is null
• caseInstanceId is null
• groupId is null
• groupIds are empty
• groupIds are null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/916d8641b865a89f. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/DeleteIdentityLinkCmd.java:62

        this.taskId = taskId;
        this.userId = userId;
        this.groupId = groupId;
        this.type = type;
    }

    protected void validateParams(String userId, String groupId, String type, String taskId) {
        if (taskId == null) {
            throw new FlowableIllegalArgumentException("taskId is null");
        }

        if (type == null) {
            throw new FlowableIllegalArgumentException("type is required when adding a new task identity link");
        }

        // Special treatment for assignee and owner: group cannot be used and userId may be null
        if (IdentityLinkType.ASSIGNEE.equals(type) || IdentityLinkType.OWNER.equals(type)) {
            if (groupId != null) {
                throw new FlowableIllegalArgumentException("Incompatible usage: cannot use type '" + type + "' together with a groupId");
            }
        } else {
            if (userId == null && groupId == null) {
                throw new FlowableIllegalArgumentException("userId and groupId cannot both be null");
            }
        }
    }

    @Override
    protected Void execute(CommandContext commandContext, TaskEntity task) {
        CmmnEngineConfiguration cmmnEngineConfiguration = CommandContextUtil.getCmmnEngineConfiguration(commandContext);
        if (IdentityLinkType.ASSIGNEE.equals(type)) {
            TaskHelper.changeTaskAssignee(task, null, cmmnEngineConfiguration);
        } else if (IdentityLinkType.OWNER.equals(type)) {
            TaskHelper.changeTaskOwner(task, null, cmmnEngineConfiguration);
        } else {
            IdentityLinkUtil.deleteTaskIdentityLinks(task, userId, groupId, type, cmmnEngineConfiguration);
        }

View on GitHub (pinned to d6d39ce1c6)