addMarker event is not called in data pipeline when range is at start of the root element

[jacekbogdanski]

📝 Provide detailed reproduction steps (if any)

1. Open https://codepen.io/jacekbogdanski/pen/XWKwRjB?editors=1010
2. Open developer tools console.
3. Refresh the page.

✔️ Expected result

Debugger statement for addMarker event should stop script execution.

❌ Actual result

Nothing happens.

The issue seems to be caused by the

ckeditor5/packages/ckeditor5-engine/src/controller/datacontroller.js

Lines 491 to 510 in eee94ce

	function _getMarkersRelativeToElement( element ) {
	const result = [];
	const doc = element.root.document;
	if ( !doc ) {
	return [];
	}
	const elementRange = ModelRange._createIn( element );
	for ( const marker of doc.model.markers ) {
	const intersection = elementRange.getIntersection( marker.getRange() );
	if ( intersection ) {
	result.push( [ marker.name, intersection ] );
	}
	}
	return result;
	}

function executed in

ckeditor5/packages/ckeditor5-engine/src/controller/datacontroller.js

Lines 240 to 248 in eee94ce

	if ( !modelElementOrFragment.is( 'documentFragment' ) ) {
	// Then, if a document element is converted, convert markers.
	// From all document markers, get those, which "intersect" with the converter element.
	const markers = _getMarkersRelativeToElement( modelElementOrFragment );
	for ( const [ name, range ] of markers ) {
	this.downcastDispatcher.convertMarkerAdd( name, range, viewWriter );
	}
	}

It looks like when the marker range is at the start or end of the root it won't be contained in the root element range and the following code will fail to process markers.

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[psmyrek]

I've added it to the iteration 44 as this is needed for HTML comments.