editor builder defaultConfig.language not apply to editor.locale

[xinglie]

📝 Provide detailed reproduction steps (if any)

1. use ckeditor5/packages/ckeditor5-build-decoupled-document to build custom editor
2. change ckeditor5/packages/ckeditor5-build-decoupled-document/src/ckeditor.js the defaultConfig.language to zh-cn

✔️ Expected result

ui is zh-cn and editor.locale also too

❌ Actual result

only ui display language in zh-cn . editor.locale language still is en,both uiLanguage and cotentLanguage

📃 Other details

---

If you'd like to see this fixed sooner, add a 👍 reaction to this post.

[FilipTokarski]

Hi, thanks for the report. Indeed after changing the language the editor.locale still shows en.
cc @ma2ciek could you take a look at this?

[Reinmar]

I confirm that it doesn't work. And it's odd.

Only setting it in create() works.

[pomek]

📝 Steps

• Use the ckeditor5-build-classic, but it happens with other builds too.

• Start the HTTP server in the packages/ckeditor5-build-classic directory (hs .)

• In the sample/index.html file, modify script tags:

  <script src="../build/ckeditor.js"></script>
  <script src="../build/translations/pl.js"></script>
  <script>
      ClassicEditor.defaultConfig.language = 'pl';
      ClassicEditor.create( document.querySelector( '#editor' ) )
    	  .then( editor => {
    		  window.editor = editor;
    	  } )
    	  .catch( error => {
    		  console.error( 'There was a problem initializing the editor.', error );
    	  } );
  </script>
  

• Type editor.locale in the console.

✔️ Expected result

  editor.locale
  Locale {uiLanguage: 'pl', contentLanguage: 'pl', uiLanguageDirection: 'ltr', contentLanguageDirection: 'ltr', t: ƒ}

❌ Actual result

  editor.locale
  Locale {uiLanguage: 'en', contentLanguage: 'en', uiLanguageDirection: 'ltr', contentLanguageDirection: 'ltr', t: ƒ}

❓ Possible solution

• Find a place where the editor.locale object is created.
• Notice that Editor#defaultConfig is used too late, and the Context class is already initialized.
• The goal is to use the language specified in the configuration object passed in the constructor or built in the editor (Editor#defaultConfig).

Solution (SPOILER)

diff --git a/packages/ckeditor5-core/src/editor/editor.js b/packages/ckeditor5-core/src/editor/editor.js
index 141a7076f2..c4677263c4 100644
--- a/packages/ckeditor5-core/src/editor/editor.js
+++ b/packages/ckeditor5-core/src/editor/editor.js
@@ -52,6 +52,8 @@ export default class Editor {
 	 * @param {Object} [config={}] The editor configuration.
 	 */
 	constructor( config = {} ) {
+		const language = config.language || this.constructor.defaultConfig.language;
+
 		/**
 		 * The editor context.
 		 * When it is not provided through the configuration, the editor creates it.
@@ -59,7 +61,7 @@ export default class Editor {
 		 * @protected
 		 * @type {module:core/context~Context}
 		 */
-		this._context = config.context || new Context( { language: config.language } );
+		this._context = config.context || new Context( { language } );
 		this._context._addEditor( this, !config.context );
 
 		// Clone the plugins to make sure that the plugin array will not be shared

Make sure to cover this change with tests:

• passing the language in the constructor
• specifying the language as #defaultConfig
• specifying the language by passing an instance of the Context class in the constructor as config.context

[pomek]

☝️ remember that the build is not refreshed when applying changes in its sources.

Please call the yarn run build --mode development --watch command in the build directory to automatically rebuild the build when changing the code.

[wimleers]

This might solve https://www.drupal.org/project/drupal/issues/3250191 🤞