mermaid-js/mermaid · error

The service [${id}] cannot be placed within itself

Error message

The service [${id}] cannot be placed within itself

What it means

Thrown by addService when the service's parent ('in' field) equals its own id. Placing a service inside itself would create a self-referential containment cycle, so the db rejects it explicitly before any structural work.

Source

Thrown at packages/mermaid/src/diagrams/architecture/architectureDb.ts:89

    this.diagramId = '';
    commonClear();
  }

  public addService({
    id,
    icon,
    in: parent,
    title,
    iconText,
  }: Omit<ArchitectureService, 'edges'>): void {
    if (this.registeredIds.has(id)) {
      throw new Error(
        `The service id [${id}] is already in use by another ${this.registeredIds.get(id)}`
      );
    }
    if (parent !== undefined) {
      if (id === parent) {
        throw new Error(`The service [${id}] cannot be placed within itself`);
      }
      if (!this.registeredIds.has(parent)) {
        throw new Error(
          `The service [${id}]'s parent does not exist. Please make sure the parent is created before this service`
        );
      }
      if (this.registeredIds.get(parent) === 'node') {
        throw new Error(`The service [${id}]'s parent is not a group`);
      }
    }

    this.registeredIds.set(id, 'node');

    this.nodes.set(id, {
      id,
      type: 'service',
      icon,
      iconText,

View on GitHub (pinned to d93e9c88c0)

Solutions

1. Ensure the parent id differs from the service id.
2. Omit the 'in' field when the service is top-level.
3. Validate id !== parent before calling addService.

Example fix

// before
db.addService({ id: 'svc', in: 'svc' });

// after
db.addService({ id: 'svc' }); // top-level
// or
db.addService({ id: 'svc', in: 'groupA' });

if (id === parent) {
  throw new Error(`Service '${id}' cannot be its own parent`);
}
db.addService({ id, in: parent });

When it happens

Trigger: addService({ id: 'X', in: 'X' }); or user text like 'service: X { ... } in X'.

Common situations: Auto-generated architecture specs where a node is mistakenly listed as its own parent, or a templating bug copies a node id into its parent slot.

Related errors

• The service [${id}]'s parent does not exist. Please make sur
• The service [${id}]'s parent is not a group
• The junction [${id}] cannot be placed within itself
• The junction [${id}]'s parent does not exist. Please make su
• The junction [${id}]'s parent is not a group

AI-assisted analysis of mermaid-js/mermaid@d93e9c88c0 (2026-08-12). Data as JSON: /api/errors/4cc7f141a0125515. Report an issue: GitHub.