List postfixers should always check type attribute and type of element.

[jodator]

The type attribute has a general name that might be used in other features. One such a feature was created here. Basically it adds a type attribute on video model element which represents the type of a media, ie video/mp4.

Unfortunately using it with conjunction with the List features leads to removing type attribute from a video element by List postfixer:

https://github.com/ckeditor/ckeditor5-list/blob/8074189abd6b406c02edd697556a267b8ae4e053/src/converters.js#L600-L620

The problem is that it should also if item is a listItem as in other checks.

[scofalik]

AFAIR without looking at the code, the problem won't be resolved by checking item.name. We will need to rename type to listType.

[jodator]

@scofalik yeah I'm checking this on schema - if it's allowed then it stays. The problem is that postfixer doesn't know which element it was previously - so it was removing it from every element (even those newly created). The simple check for now which I've added is to check schema.

Also this should be cleaned upon resolving this: https://github.com/ckeditor/ckeditor5-engine/issues/1228.

[Reinmar]

The problem is deeper. Much deeper. The type may be allowed on <listItem> and <video>. What if someone renames one to another? This postfixer, even when based on the schema (as after ckeditor/ckeditor5-engine#1228), will keep this attribute. The problem is that its value will be invalid in the context of the new element.

This indicates that we should rename this attribute to listType. Attributes belonging to specific elements should be prefixed with their names (or made unique in some other way).

Another example – the same situation might occur if <p alignment> was renamed to <image>. The <image> might allow alignment and the same situation would occur again. However, <image> should not use alignment attribute (unless, of course, it's handled by the same feature which handles it on paragraphs). It should use imageAlignment. Just like we have imageStyle instead of style (which was caused by a completely different problem, but turns out to be good :D).

So, I'm ok with renaming type to listType. We should go further and rename also listItem's indent to listIndent.

As for the image's src and alt, we might rename them too unless we want to make an exception for object elements which are never going to be renamed to anything (so their attributes won't leak), but then we have to live with that inconsistent imageStyle.

[Reinmar]

So, I'm ok with renaming type to listType. We should go further and rename also listItem's indent to listIndent.

@scofalik gave 👍 to that and @pjasiun was fine with this change too. Let's do it, then.