execCommand("indent") conflicts with the content model of <ul>/<ol>

[saschanaz]

Consider the following tree:

<ul>
<li>first</li>
<li>second</li>
</ul>

Here, execCommand("indent") on the second list item generates the following tree:

<ul>
<li>first</li>
<ul><li>second</li></ul>
</ul>

The resulting tree inserts a <ul> inside another <ul>, conflicting with HTML:

Content model:
Zero or more li and script-supporting elements.

I guess we have two options:

• Change the indentation behavior: I don't think we want to change the behavior that has been there for decades, though. The previous author also preferred the current behavior because of algorithm simplicity.
• Change HTML. This was once rejected but IMO is the way to go for web compatibility.

Pinging @annevk for the HTML part.

[annevk]

Well, we could also do nothing or add indentCorrectly or some such.

Having said that, I recommend opening an issue against the HTML Standard to see what people think.

[rniwa]

• Change the indentation behavior: I don't think we want to change the behavior that has been there for decades, though. The previous author also preferred the current behavior because of algorithm simplicity.

We definitely can't change this behavior now. A lot of content depends on this behavior.

• Change HTML. This was once rejected but IMO is the way to go for web compatibility.

I support changing the HTML spec to allow this construct although it's not really a show stopper given all browsers interoperate anyway.

[masayuki-nakano]

I agree with @rniwa -san. <li> containing only sub list element may also have a bullet, and I don't think this style is better because word processors do not use this style.