Function nextShellRunRecord

packages/core/src/shell-run.ts:384–416

(current: ShellRunRecord, patch: ShellRunPatch)

 * is what callers use to tell a durable write from a redundant one.
 */
export function nextShellRunRecord(current: ShellRunRecord, patch: ShellRunPatch): ShellRunRecord {
  assertShellRunPatch(patch);
  const { sessionId, shellRunId } = current;
  if (patch.output && patch.output.mode !== current.output.mode) {
    throw new Error(`ShellRun output mode is immutable: ${current.output.mode}`);
  }
  const effectivePatch =
    current.observedAt !== undefined && Object.hasOwn(patch, 'observedAt')
      ? { ...patch, observedAt: current.observedAt }
      : patch;
  const candidate = normalizeShellRunRecord(
    { ...current, ...effectivePatch, sessionId, shellRunId, revision: current.revision },
    sessionId,
    shellRunId,
  );
  if (!isValidShellRunStatusTransition(current.status, candidate.status)) {
    throw new Error(`Invalid ShellRun status transition: ${current.status} -> ${candidate.status}`);
  }
  if (
    isTerminalShellRunStatus(current.status) &&
    (candidate.completedAt !== current.completedAt ||
      candidate.exitCode !== current.exitCode ||
      candidate.failureMessage !== current.failureMessage)
  ) {
    throw new Error(`ShellRun terminal outcome is immutable: ${current.status}`);
  }
  if (shellRunRecordsEqual(candidate, current)) return current;
  return normalizeShellRunRecord(
    { ...candidate, revision: current.revision + 1 },
    sessionId,
    shellRunId,
  );
}

/**
 * Structural equality for normalized ShellRun records. Records are plain