fix: fix write-translations warning for theme-common translations (#5398)

packages/docusaurus/src/commands/writeTranslations.ts

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 import {ConfigOptions, InitializedPlugin} from '@docusaurus/types';
+import path from 'path';
 import {loadContext, loadPluginConfigs} from '../server';
 import initPlugins from '../server/plugins/init';
 
@@ -15,9 +16,27 @@ import {
   getPluginsDefaultCodeTranslationMessages,
   applyDefaultCodeTranslations,
 } from '../server/translations/translations';
-import {extractSiteSourceCodeTranslations} from '../server/translations/translationsExtractor';
+import {
+  extractSiteSourceCodeTranslations,
+  globSourceCodeFilePaths,
+} from '../server/translations/translationsExtractor';
 import {getCustomBabelConfigFilePath, getBabelOptions} from '../webpack/utils';
 
+// This is a hack, so that @docusaurus/theme-common translations are extracted!
+// A theme doesn't have a way to express that one of its dependency (like @docusaurus/theme-common) also has translations to extract
+// Instead of introducing a new lifecycle (like plugin.getThemeTranslationPaths() ?)
+// We just make an exception and assume that Docusaurus user is using an official theme
+async function getExtraSourceCodeFilePaths(): Promise<string[]> {
+  try {
+    const themeCommonSourceDir = path.dirname(
+      require.resolve('@docusaurus/theme-common/lib'),
+    );
+    return globSourceCodeFilePaths([themeCommonSourceDir]);
+  } catch (e) {
+    return []; // User may not use a Docusaurus official theme? Quite unlikely...
+  }
+}
+
 async function writePluginTranslationFiles({
   siteDir,
   plugin,
@@ -80,6 +99,7 @@ Available locales are: ${context.i18n.locales.join(',')}.`,
     siteDir,
     plugins,
     babelOptions,
+    await getExtraSourceCodeFilePaths(),
   );
   const defaultCodeMessages = await getPluginsDefaultCodeTranslationMessages(
     plugins,

packages/docusaurus/src/server/translations/translationsExtractor.ts

@@ -80,6 +80,7 @@ export async function extractSiteSourceCodeTranslations(
   siteDir: string,
   plugins: InitializedPlugin[],
   babelOptions: TransformOptions,
+  extraSourceCodeFilePaths: string[] = [],
 ): Promise<TranslationFileContent> {
   // Should we warn here if the same translation "key" is found in multiple source code files?
   function toTranslationFileContent(
@@ -92,8 +93,13 @@ export async function extractSiteSourceCodeTranslations(
 
   const sourceCodeFilePaths = await getSourceCodeFilePaths(siteDir, plugins);
 
+  const allSourceCodeFilePaths = [
+    ...sourceCodeFilePaths,
+    ...extraSourceCodeFilePaths,
+  ];
+
   const sourceCodeFilesTranslations = await extractAllSourceCodeFileTranslations(
-    sourceCodeFilePaths,
+    allSourceCodeFilePaths,
     babelOptions,
   );