Possible to paste links inside a button

[johngodley]

The button block has format tools for bold, italic, and strikethrough. However, if you paste content it's possible to insert additional formatting, including links. This leads to nested links, which is not valid HTML.

Here's the button editor:

And copy/pasting some text with links results in this:

Looking at the HTML we have nested links:

<div class="wp-block-button">
  <a class="wp-block-button__link">She is also the daughter of <a href="http://mlp.wikia.com/wiki/Twilight_Velvet_and_Night_Light">Twilight Velvet and Night Light</a></a>
</div>

To Reproduce
Steps to reproduce the behavior:

1. Create button block
2. Copy some text from a web page with links
3. Paste into the button

Expected behavior
Links to be stripped

[johngodley]

Also noting that after saving the post and then reloading the page, the block is shown invalid.

[ellatrix]

Duplicate of #7591.

[Inwerpsel]

Duplicate of #7591.

The referred ticket would create an interface that would allow to more easily fix this issue, but it would not do so by itself, so really it's not a duplicate of this one. This is a bug report, so why close it unless the bug is fixed or there is an other bug report that duplicates it?