flowable/flowable-engine · error · FlowableIllegalArgumentException

Cannot set global variable

Error message

Cannot set global variable '${name}' on task '${task.getId()}', task is not part of process.

What it means

A standalone task (not linked to a process execution, executionId == null) cannot hold global variables, since global scope means the execution/process scope. Flowable throws FlowableIllegalArgumentException when a global-scope variable is set on such a task.

Solutions

1. Use "variableScope": "local" (or omit scope; defaults to local) for standalone tasks
2. Attach the task to a process instance if global variables are genuinely needed
3. Handle the error in clients that accept both process and standalone tasks

Example fix

// before
{"name": "priority", "value": 3, "variableScope": "global"}   // standalone task
// after
{"name": "priority", "value": 3, "variableScope": "local"}

const task = await api.get(`/runtime/tasks/${taskId}`); if (!task.data.executionId && scope === 'global') { throw new Error('Standalone task: only local variables allowed'); }

function canSetGlobal(task) { return Boolean(task && task.executionId); }

try { await setVariable(taskId, var); } catch (e) { if (isIllegalArgument(e) && /not part of process/.test(e.message)) { await setVariable(taskId, {...var, variableScope: 'local'}); } else { throw e; } }

When it happens

Trigger: POST/PUT /runtime/tasks/{taskId}/variables with "variableScope": "global" on a task created outside any process instance (e.g. via the standalone task REST/TaskService API).

Common situations: Standalone tasks created via POST /runtime/tasks; code paths reused between process tasks and standalone tasks; assuming every task belongs to a process; task's process instance already ended so execution link is gone.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Cannot set global variables on task
• Can only unacquire BPMN or CMMN external job. Job with id
• Cannot set global variables on task
• Only allowed to update multiple variables in the same scope.
• Only allowed to update multiple variables in the same scope.

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/9648cedc6ecac5bb. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-rest/src/main/java/org/flowable/rest/service/api/runtime/task/TaskVariableBaseResource.java:249

        if (restApiInterceptor != null) {
            if (isNew) {
                restApiInterceptor.createTaskVariables(task, Collections.singletonMap(name, value), scope);
            } else {
                restApiInterceptor.updateTaskVariables(task, Collections.singletonMap(name, value), scope);
            }
        }

        if (scope == RestVariableScope.LOCAL) {
            taskService.setVariableLocal(task.getId(), name, value);
        } else {
            if (task.getExecutionId() != null) {
                // Explicitly set on execution, setting non-local variable on
                // task will override local-variable if exists
                runtimeService.setVariable(task.getExecutionId(), name, value);
            } else {
                // Standalone task, no global variables possible
                throw new FlowableIllegalArgumentException("Cannot set global variable '" + name + "' on task '" + task.getId() + "', task is not part of process.");
            }
        }
    }
}

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