deepseek-ai/deepseek-harness · error · Error

session "${id}" already exists

Error message

session "${id}" already exists

What it means

Error "session "${id}" already exists" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/index.ts:918

   * cross-package primitives and a caller may interleave arbitrary work (or
   * another create) between them, so a stale prepared session must NOT overwrite
   * a live store entry of the same id — its detach disposer would later delete
   * the REAL session. The {@link create} convenience and the agent factory call
   * the two back-to-back so they never trip this, but the public API cannot
   * assume that.
   *
   * @param session - a {@link prepare}d session not yet in the store.
   * @returns the detach disposer (publication hooks + store removal). When called from
   *   a synchronous `session/created` listener, removal and disposal wait until
   *   that creation dispatch unwinds.
   * @throws if a session with this id is already in the store.
   */
  enter(session: Session): () => void {
    const id = session.id
    const carrier = scopeTarget(session, scopeOf(this.ctx))
    // This is the authoritative collision boundary after arbitrary unpublished
    // preparation. Only one exact same-id transaction can publish.
    if (this.store.has(id)) throw new Error(`session "${id}" already exists`)
    if (attachments.has(session)) throw new Error(`session "${id}" is already attached to a store`)
    const entry: SessionEntry = {
      id,
      session,
      carrier,
      emitCtx: this.ctx,
      announced: false,
      announcing: false,
      appending: false,
      detachRequested: false,
      detach: () => { this.detachEntered(entry) },
    }
    this.store.set(id, entry)
    attachments.set(session, entry)
    let entered = true
    const detach = (): void => {
      if (!entered) return
      entered = false

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/core/session/src/index.ts:918 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/02e7a8cf3af8eba9. Report an issue: GitHub.