feat(i18n): compose pairing records during merges

scripts/translation-pairing-record.ts

@@ -0,0 +1,99 @@
+/** Canonical paths, parsing, and rendering for bilingual pairing records. */
+
+import { basename } from 'node:path'
+
+/** The three repository-relative paths that form one bilingual pair. */
+export interface TranslationPairPaths {
+  /** English document path. */
+  source: string
+  /** Simplified Chinese document path. */
+  zh: string
+  /** Generated consistency-record path. */
+  meta: string
+}
+
+/** The two content hashes recorded for a bilingual pair. */
+export interface TranslationPairingRecord {
+  /** Git blob hash of the English document. */
+  sourceHash: string
+  /** Git blob hash of the Simplified Chinese document. */
+  zhHash: string
+}
+
+const META_LINE = /^([^:#]+\.md): ([0-9a-f]{40})$/
+
+/**
+ * Derive the counterpart and consistency-record paths from an English document.
+ *
+ * @param source - Repository-relative English Markdown path.
+ * @returns The complete three-path pair.
+ */
+export function translationPairPaths(source: string): TranslationPairPaths {
+  if (!source.endsWith('.md') || source.endsWith('.zh.md')) {
+    throw new Error(`expected an English Markdown path, received ${JSON.stringify(source)}`)
+  }
+  return {
+    source,
+    zh: source.replace(/\.md$/, '.zh.md'),
+    meta: source.replace(/\.md$/, '.i18n.yaml'),
+  }
+}
+
+/**
+ * Derive one pair from its consistency-record path.
+ *
+ * @param meta - Repository-relative `foo.i18n.yaml` path.
+ * @returns The complete three-path pair.
+ */
+export function translationPairPathsFromMeta(meta: string): TranslationPairPaths {
+  if (!meta.endsWith('.i18n.yaml')) {
+    throw new Error(`expected a bilingual consistency-record path, received ${JSON.stringify(meta)}`)
+  }
+  return translationPairPaths(meta.replace(/\.i18n\.yaml$/, '.md'))
+}
+
+/**
+ * Parse a consistency record for its expected sibling names.
+ *
+ * @param content - Complete sidecar text.
+ * @param paths - Expected sibling paths.
+ * @returns The two hashes, or `undefined` for malformed, duplicate, or unexpected keys.
+ */
+export function parseTranslationPairingRecord(
+  content: string,
+  paths: TranslationPairPaths,
+): TranslationPairingRecord | undefined {
+  const hashes = new Map<string, string>()
+  for (const line of content.split('\n')) {
+    if (line === '' || line.startsWith('#')) continue
+    const match = META_LINE.exec(line)
+    if (!match?.[1] || !match[2] || hashes.has(match[1])) return undefined
+    hashes.set(match[1], match[2])
+  }
+  const sourceHash = hashes.get(basename(paths.source))
+  const zhHash = hashes.get(basename(paths.zh))
+  if (hashes.size !== 2 || sourceHash === undefined || zhHash === undefined) return undefined
+  return { sourceHash, zhHash }
+}
+
+/**
+ * Render the canonical consistency record for a pair.
+ *
+ * @param paths - Pair paths written into the record and its recovery command.
+ * @param record - Confirmed content hashes.
+ * @returns Canonical YAML text with exactly one trailing newline.
+ */
+export function renderTranslationPairingRecord(
+  paths: TranslationPairPaths,
+  record: TranslationPairingRecord,
+): string {
+  return [
+    '# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each',
+    '# side as of the last confirmed-consistent state. Both languages carry equal authority;',
+    '# after editing either side, bring the other along and re-record with:',
+    `#   pnpm run verify-translation-pairing --write ${paths.source}`,
+    `${basename(paths.source)}: ${record.sourceHash}`,
+    `${basename(paths.zh)}: ${record.zhHash}`,
+    '',
+  ].join('\n')
+}