HTML Tags not closing with markdown extension

[natsch93]

Describe the issue

HTML Tags are not closing automatically with markdown() extension.

<div> seems to work fine, and closes automatically.

But trying other elements like <b>, <a>, <label>, etc. does not work, unless a <div></div> is present above.

Reproduction steps:

• Open the reproduction link
• Enter <b>, notice how doesn't auto-close
• Delete <b> and enter <div>, <div> auto-closes successfully
• Go below the <div></div> and enter <b> again, this time auto-close is successful for <b>

codemirror-markdown-html-auto-close-tag-issue.mp4

Browser and platform

Chrome

Reproduction link

https://codemirror.net/try/#c=aW1wb3J0IHsgYmFzaWNTZXR1cCwgRWRpdG9yVmlldyB9IGZyb20gImNvZGVtaXJyb3IiCmltcG9ydCB7IG1hcmtkb3duIH0gZnJvbSAiQGNvZGVtaXJyb3IvbGFuZy1tYXJrZG93biIKCmxldCB2aWV3ID0gbmV3IEVkaXRvclZpZXcoewogIGRvYzogIiIsCiAgZXh0ZW5zaW9uczogWwogICAgYmFzaWNTZXR1cCwKICAgIG1hcmtkb3duKCksCiAgXSwKICBwYXJlbnQ6IGRvY3VtZW50LmJvZHkKfSk=

[marijnh]

What's happening is that the Markdown parser isn't yet parsing <b as an HTML tag, whereas it is <div (or <p or any block tag). As such, HTML-specific behavior like the auto-closing isn't firing when a > is typed. This parsing behavior matches the CommonMark spec (compare this and this example), but I agree that the outcome isn't great in this situation.

It seems kind of hard to work around, though. The closing logic is implemented with an input handler, which runs before the > is in the document (and thus in the parse).