Type of report

CKEDITOR.tools.convertToPx does not properly support frameworks that replace HTML body but don't reload Javascript libraries, such as Hotwire Turbo.

More accurately, anything that clears or replaces the DOM body will break this CKEDITOR.tools.convertToPx

Provide detailed reproduction steps (if any)

This surfaces when using the autogrow plugin, but anything that relies on editor.resize() will trigger this behavior. Instantiate an editor, clear the DOM body, create new HTML for an editor and instantiate it, then call resize on it.

Expected result

The editor should resize to the size specified.

Actual result

The editor resizes to a zero height.

Other details

This is because CKEDITOR.tools.convertToPx declares a variable calculator which it uses to memoize an element appended to the body used for the calculation.

But if anything clears the DOM body, this "calculator" element no longer exists, even though the variable still points to the disembodied element. This causes the incorrect calculation that—at least in Chrome—returns zero.

The fix is to also check calculator.$.isConnected to see whether it is connected to the DOM:

if ( !calculator ) {
	calculator = CKEDITOR.dom.element.createFromHtml( '<div style="position:absolute;left:-9999px;' +
		'top:-9999px;margin:0px;padding:0px;border:0px;"' +
		'></div>', CKEDITOR.document );
	CKEDITOR.document.getBody().append( calculator );
}
else
{
	if ( !calculator.$.isConnected ) {
		// Re-attach to DOM if it got disconnected.
		CKEDITOR.document.getBody().append( calculator );
	}
}