Add language of parts plugin

Tagging for Contribution event

Fixing tags.

working on this so assigning to myself

I have converted PNG to SVG for the language icon as CKEditor doesn't provide an icon for it. Please check if we need to update it.

Need to provide TextPartLanguageOption.

I was trying to follow the same pattern as "imageUpload" for id but facing the below error so I set the plugin id to "language".

Drupal\Core\Config\ConfigValueException: ckeditor5.language key contains a dot which is not supported. in Drupal\Core\Config\ConfigBase->validateKeys() (line 211 of core/lib/Drupal/Core/Config/ConfigBase.php).

@Wim Leers Forgot to upload the screenshot showing config works, please check the attached screenshots. The screenshot previously attached were before creating the configuration form.

In CKEditor 5, AFAICT the default plugin configuration really should be set in ckeditor5.ckeditor5.yml, under plugin_config.

will work on this.

I will work on the test case part.

working on this so assigning to myself

After adding this plugin kernel test case is failing due to the order of plugins in case 2

Case 2: The CKEditor 5 layercake plugin is available and the library should be loaded without having to enable plugins.

1) Drupal\Tests\ckeditor5\Kernel\CKEditor5PluginManagerTest::testEnabledPlugins
Failed asserting that two arrays are identical.
--- Expected
+++ Actual
@@ @@
     14 => 'ckeditor5.superscript'
     15 => 'ckeditor5.table'
     16 => 'ckeditor5.underline'
-    17 => 'language'
-    18 => 'ckeditor5_test.layercake'
+    17 => 'ckeditor5_test.layercake'
+    18 => 'language'
 )

This issue might come up with each new plugin added, is it ok to sort an array and assert them or the order of the plugin is important here?

   $default_plugins_with_layercake = array_merge($default_plugins, ['ckeditor5_test.layercake']);
    asort($default_plugins_with_layercake);
    $this->assertSame(array_values($default_plugins_with_layercake), $plugin_ids);

In test case we are using $plugin_ids = array_keys($this->manager->getEnabledDefinitions($editor));

getEnabledDefinitions function sorting plugin ids so I think we can use the code from comment 12 .

 public function getEnabledDefinitions(Editor $editor) {
    $definitions = $this->getDefinitions();
    ksort($definitions);
    foreach ($definitions as $plugin_id => $definition) {
      $plugin = $this->createInstance($plugin_id);

In CKEditor 5, AFAICT the default plugin configuration really should be set in ckeditor5.ckeditor5.yml, under plugin_config.

This is fixed.

Added tests for the language of parts plugin.
Fixed failing kernel test after adding a plugin.

This works well, the settings form lets a user pick which set of languages to use, which matches the lists CKEditor 4 loads.
I'm also excited to see the `settingsForm` used here, I think it's the first new plugin that has configuration (besides ImageUpload)
I left some feedback in the issue fork for a few changes, but this is really close, nice work @anand.toshniwal93 !

working on this so assigning to myself

When I test testLanguageOfPartsPlugin locally it fails, but it seems to be because the dropdown is opening up and it's cut off.
Curious if the testbot will pass still, I can't see where anything changed.

There's also an incomplete schema exception for editor.editor.ckeditor5:settings.plugins.language "missing schema"

This should be back to needs review, I added the schema and rebased off the latest 1.0.x.

Updated the postponed issues, thanks!