deepseek-ai/deepseek-harness · error · Error

sourceEventSeqs must reference earlier events: ${nonEarlierS

Error message

sourceEventSeqs must reference earlier events: ${nonEarlierSource} >= current seq ${event.seq}

What it means

Error "sourceEventSeqs must reference earlier events: ${nonEarlierSource} >= current seq ${event.seq}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/surface.ts:236

    if (!Array.isArray(raw)) {
      throw new Error(`sourceEventSeqs on event at seq ${event.seq} must be an array when present`)
    }
    if (raw.length === 0 && event.type !== 'assistant/message') {
      throw new Error('sourceEventSeqs must not be empty except on assistant/message')
    }
    let nonEarlierSource: number | undefined
    for (const source of raw) {
      if (!isEventSeq(source)) {
        throw new Error(`session event "${event.type}" sourceEventSeqs must densely contain non-negative safe integers`)
      }
      sources.add(source)
      if (nonEarlierSource === undefined && source >= event.seq) nonEarlierSource = source
    }
    if (sources.size !== raw.length) {
      throw new Error('sourceEventSeqs must not contain duplicates')
    }
    if (nonEarlierSource !== undefined) {
      throw new Error(`sourceEventSeqs must reference earlier events: ${nonEarlierSource} >= current seq ${event.seq}`)
    }
  }
  const missing = shadowedSeqs.filter(seq => !sources.has(seq))
  if (missing.length > 0) {
    throw new Error(`surface replace: sourceEventSeqs must include every shadowed surface node; missing ${missing.join(', ')}`)
  }
}

/** Locate one replacement range without mutating the current fold state. */
function replacementRange(
  state: SurfaceFoldState,
  op: Extract<SurfaceOp, { op: 'replace' }>,
): Pick<SurfaceReplacePlan, 'startIdx' | 'endIdx' | 'shadowedSeqs'> {
  const startIdx = state.nodes.indexOf(op.start)
  if (startIdx === -1) {
    throw new Error(`surface replace: start seq ${op.start} not found in surface`)
  }
  const endIdx = state.nodes.indexOf(op.end)

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/core/session/src/surface.ts:236 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/286600438970ec15. Report an issue: GitHub.