Function appendEntryToFile

src/utils/sessionStorage.ts:2611–2623

(
  fullPath: string,
  entry: Record<string, unknown>,
)

 */
/* eslint-disable custom-rules/no-sync-fs -- sync callers (exit cleanup, materialize) */
function appendEntryToFile(
  fullPath: string,
  entry: Record<string, unknown>,
): void {
  const fs = getFsImplementation()
  const line = jsonStringify(entry) + '\n'
  try {
    fs.appendFileSync(fullPath, line, { mode: 0o600 })
  } catch {
    fs.mkdirSync(dirname(fullPath), { mode: 0o700 })
    fs.appendFileSync(fullPath, line, { mode: 0o600 })
  }
}

/**
 * Sync tail read for reAppendSessionMetadata's external-writer check.