deepseek-ai/deepseek-harness · error

[web-runtime] lineage cycle at ${s.sessionId}; emitting as r

Error message

[web-runtime] lineage cycle at ${s.sessionId}; emitting as root

What it means

Error "[web-runtime] lineage cycle at ${s.sessionId}; emitting as root" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/client/runtime/src/client/sessions/lineage.ts:73

  for (const s of summaries) byId.set(s.sessionId, s)

  const children = new Map<SessionId, TitledSessionSummary[]>()
  const roots: TitledSessionSummary[] = []
  for (const s of summaries) {
    if (s.parentSessionId !== undefined && byId.has(s.parentSessionId)) {
      const list = children.get(s.parentSessionId) ?? []
      list.push(s)
      children.set(s.parentSessionId, list)
    } else {
      roots.push(s) // root, or an orphan whose parent is absent from summaries (degrade to root, never drop)
    }
  }

  const out: SessionListEntry[] = []
  const visited = new Set<SessionId>()
  const walk = (s: TitledSessionSummary, depth: number): void => {
    if (visited.has(s.sessionId)) {
      console.warn(`[web-runtime] lineage cycle at ${s.sessionId}; emitting as root`)
      return
    }
    visited.add(s.sessionId)
    const pendingInteraction = pendingInteractions?.get(s.sessionId)
    out.push({
      ...s,
      ...(pendingInteraction === undefined ? {} : { pendingInteraction }),
      completed: completed?.has(s.sessionId) ?? false,
      depth,
    })
    const kids = children.get(s.sessionId)
    if (kids === undefined) return
    for (const kid of kids) walk(kid, depth + 1)
  }
  for (const root of roots) walk(root, 0)
  // Cycle members (unreachable from any root): emit as roots so no entry is lost.
  for (const s of summaries) {
    if (!visited.has(s.sessionId)) walk(s, 0)

View on GitHub (pinned to b150a551b8)

Solutions

1. Inspect session lineage data for a cycle at the reported sessionId and remove the circular parent reference.

When it happens

Trigger: Thrown at packages/client/runtime/src/client/sessions/lineage.ts:73 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/27697537aaa86021. Report an issue: GitHub.