Close SourceEditing view on plugin disabling

[l-lejman]

Suggested merge commit message (convention)

Other (source-editing): The SourceEditing plugin now closes its view upon being disabled, preventing users from remaining stuck in this mode.

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Additional information

A change is needed to ensure that SourceEditing is properly closed when CommentsOnly mode is enabled or when SourceEditing is disabled by API calls. These two plugins should not operate simultaneously.

[f1ames]

It generally works as intended, but there is more general topic to discuss. What happens with any modifications while the source mode gets disabled programmatically? The current implementation is done in a way that all changes are automatically propagated (I also reported a related issue which somehow touches it - #17738).

This is because when isSourceEditingMode flag changed (which basically turns source mode on/off in every case), the editor data is updated:

ckeditor5/packages/ckeditor5-source-editing/src/sourceediting.ts

Lines 124 to 133 in 9333cc9

	this.on( 'change:isSourceEditingMode', ( evt, name, isSourceEditingMode ) => {
	if ( isSourceEditingMode ) {
	this._hideVisibleDialog();
	this._showSourceEditing();
	this._disableCommands();
	} else {
	this._hideSourceEditing();
	this._enableCommands();
	}
	} );

ckeditor5/packages/ckeditor5-source-editing/src/sourceediting.ts

Lines 294 to 298 in 9333cc9

	private _hideSourceEditing(): void {
	const editor = this.editor;
	const editingView = editor.editing.view;
	this.updateEditorData();

I'll bring this topic to broader discussion so we can decide how to move forward. Maybe that was one of the reasons it earlier applied read-only mode in similar scenarios instead of switching back to WYSIWYG mode?

[scofalik]

Sorry for the confusion, as I suggested that maybe source editing should close if the plugin is disabled, but I didn't fully understand how this plugin operates now and what we want to achieve.

Right now, the plugin has some issues, both from:

• product perspective (e.g. if read-only mode kicks in when you are in source mode, you are stuck in it, also it should be possible to see the source in read-only mode, just not change it), and
• from code perspective (e.g. the plugin does not have any commands and the logic is written in unfortunate way, e.g. closing source mode is coupled with saving the data).

We won't solve all the problems without a bigger refactor, so let's stick to something that makes sense and is quick.

Right now, when you switch to read-only following things happen in source editing plugin:

1. Toolbar and menu bar buttons for source mode are disabled. You can't switch to/from the source mode.
2. Textarea is disabled.

Let's go with exactly same behavior for when the plugin is disabled (e.g. for comments-only mode, note, that comments-only mode will be set to true or false at the beginning of the editor initialization and likely won't change after).

So, if the plugin gets disabled (comments-only is activated), we will disable the buttons and textareas.

And I think that for this behavior we don't need any change in the plugin, correct?