deepseek-ai/deepseek-harness · error · Error

surface replace: start seq ${op.start} (index ${startIdx}) i

Error message

surface replace: start seq ${op.start} (index ${startIdx}) is after end seq ${op.end} (index ${endIdx})

What it means

Error "surface replace: start seq ${op.start} (index ${startIdx}) is after end seq ${op.end} (index ${endIdx})" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/surface.ts:259

    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)
  if (endIdx === -1) {
    throw new Error(`surface replace: end seq ${op.end} not found in surface`)
  }
  if (startIdx > endIdx) {
    throw new Error(`surface replace: start seq ${op.start} (index ${startIdx}) is after end seq ${op.end} (index ${endIdx})`)
  }
  return {
    startIdx,
    endIdx,
    shadowedSeqs: state.nodes.slice(startIdx, endIdx + 1),
  }
}

/**
 * Deep structural equality over the session-event JSON value domain
 * (null/boolean/number/string, arrays, plain objects). Replaces
 * `node:util`'s isDeepStrictEqual to keep this module browser-safe.
 */
function isDeepEqualJson(a: unknown, b: unknown): boolean {
  if (a === b) return true
  if (Array.isArray(a) || Array.isArray(b)) {
    if (!Array.isArray(a) || !Array.isArray(b) || a.length !== b.length) return false
    return a.every((item, i) => isDeepEqualJson(item, b[i]))

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/core/session/src/surface.ts:259 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/de632d28296faae5. Report an issue: GitHub.