Use of loop and autostart in <audio> causes unknown error

[Ruifrok]

Issue Overview

Use of loop and autostart in causes unknown error

Steps to Reproduce (for bugs)

1. Add audio block
2. Use edit as HTML to add the loop and/or autoplay attributes to the tag.
3. Update the post.
4. message: block has been changed
5. Click edit as HTML in the block.
6. block shows unknown error. No HTML is shown
7. Switch to code editor: the string ="" is added to the controls, loop and autoplay attributes

Firefox 59.0.3, Chrome 66, Gutenberg 2.8

Expected Behavior

Preferably the addition of loop and autoplay options(checkboxes), as are available when using the audio shortcode.
At least allow for the error free addition of attributes.

[danielbachhuber]

Thanks for the report, @Ruifrok.

This issue is related to a general class of issues stemming from the Gutenberg's decision to drop "unknown" HTML attributes. I think we'll need to address this in some way before WordPress 5.0.

[danielbachhuber]

Flagging this as Needs Design Feedback. I'd like to add checkboxes for loop and autoplay to the Audio block so we handle them as a part of block transformation. Seem reasonable?

[Ruifrok]

Would solve the problem, I think

[karmatosed]

I am fine with those settings but as it's additional to what we have right now in WordPress it would be a lower priority. I think the bug here is to fix that it can be done in way it is now - that also wouldn't require any new interface.

[Ruifrok]

If it is additional is disputable, I think. You are right when adding audio initially. However when you click the pencil mark for the added audio, a screen opens where you can set preload, autoplay and loop.
But as mentioned, I can live with a solution where I can add html-allowed attributes without generating an error. The question is: Do you want to force code editing where we now have screen to choose the attributes.