Function findAssistantIndexAfterPrefix

test/harness/replayingCapiProxy.ts:1293–1328

(
  requestMessages: NormalizedMessage[],
  savedMessages: NormalizedMessage[],
)

// Checks if requestMessages is a prefix of savedMessages,
// and returns the index of the next assistant message if found.
function findAssistantIndexAfterPrefix(
  requestMessages: NormalizedMessage[],
  savedMessages: NormalizedMessage[],
): number | undefined {
  const logFile = process.env.PROXY_DEBUG_LOG;
  const log = (msg: string) => { if (logFile) try { appendFileSync(logFile, msg + "\n"); } catch {} };

  if (requestMessages.length >= savedMessages.length) {
    log(`prefix check failed: request.length=${requestMessages.length} >= saved.length=${savedMessages.length}`);
    return undefined;
  }

  for (let i = 0; i < requestMessages.length; i++) {
    const reqMsg = JSON.stringify(requestMessages[i]);
    const savedMsg = JSON.stringify(savedMessages[i]);
    if (reqMsg !== savedMsg) {
      log(`mismatch at index ${i}:`);
      log(`  REQ:   ${reqMsg.substring(0, 1000)}`);
      log(`  SAVED: ${savedMsg.substring(0, 1000)}`);
      return undefined;
    }
  }

  // The next message after the prefix should be an assistant message
  const nextIndex = requestMessages.length;
  if (
    nextIndex < savedMessages.length &&
    savedMessages[nextIndex].role === "assistant"
  ) {
    log(`MATCH found at index ${nextIndex}`);
    return nextIndex;
  }

  log(`no assistant at nextIndex=${nextIndex}, saved.length=${savedMessages.length}`);
  return undefined;
}

function expandWorkDir(
  content: string | undefined,