fix(docs): versioning CLI should copy localized translation file current.json to version-<v>.json (#10875)

Co-authored-by: Sungchang Ha <bryan98@naver.com>

packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/simple-site/i18n/zh-Hans/docusaurus-plugin-content-docs/current.json

@@ -0,0 +1,3 @@
+{
+  "some.key": "some translation"
+}

packages/docusaurus-plugin-content-docs/src/cli.ts

@@ -14,6 +14,7 @@ import {
   getVersionDocsDirPath,
   getVersionSidebarsPath,
   getDocsDirPathLocalized,
+  getPluginDirPathLocalized,
   readVersionsFile,
 } from './versions/files';
 import {validateVersionName} from './versions/validation';
@@ -123,6 +124,23 @@ async function cliDocsVersionCommand(
               versionName: version,
             });
       await fs.copy(docsDir, newVersionDir);
+
+      // Copy version JSON translation file for this locale
+      // i18n/<l>/docusaurus-plugin-content-docs/current.json => version-v1.json
+      // See https://docusaurus.io/docs/next/api/plugins/@docusaurus/plugin-content-docs#translation-files-location
+      if (locale !== i18n.defaultLocale) {
+        const dir = getPluginDirPathLocalized({
+          localizationDir,
+          pluginId,
+        });
+        const sourceFile = path.join(dir, 'current.json');
+        const dest = path.join(dir, `version-${version}.json`);
+        if (await fs.pathExists(sourceFile)) {
+          await fs.copy(sourceFile, dest);
+        } else {
+          logger.warn`${pluginIdLogPrefix}: i18n translation file does not exist in path=${sourceFile}. Skipping.`;
+        }
+      }
     }),
   );
 

packages/docusaurus-plugin-content-docs/src/versions/files.ts

@@ -75,6 +75,21 @@ export function getDocsDirPathLocalized({
   });
 }
 
+export function getPluginDirPathLocalized({
+  localizationDir,
+  pluginId,
+}: {
+  localizationDir: string;
+  pluginId: string;
+}): string {
+  return getPluginI18nPath({
+    localizationDir,
+    pluginName: 'docusaurus-plugin-content-docs',
+    pluginId,
+    subPaths: [],
+  });
+}
+
 /** `community` => `[siteDir]/community_versions.json` */
 export function getVersionsFilePath(siteDir: string, pluginId: string): string {
   return path.join(siteDir, addPluginIdPrefix(VERSIONS_JSON_FILE, pluginId));