Embeds: pasting a non-embeddable Facebook URL throws a TypeError

[jsnajdr]

To reproduce
Start editing a post and paste the following URL:

https://www.facebook.com/informationisbeautiful/

It's a link to a Facebook page that is not embeddable. The oEmbed Proxy REST request returns a response with html: false:

This then leads to an error being reported in console:

The offending function is isFromWordPress that calls html.includes() on its html argument that is false.

The embed block UI then ends up like this:

Expected behavior
When testing on WordPress.com or on a self-hosted WordPress 5.4.2 with default editor, I see something more correct:

The fact that this works correctly with older versions of Gutenberg that are not bleeding edge suggests the bug is a recent regression. Maybe the refactoring in #24090 by @ntsekouras is the cause?

Editor version (please complete the following information):

• WordPress version: 5.5.1
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? Gutenberg plugin
• If the Gutenberg plugin is installed, which version is it? built from master

[ntsekouras]

Hey @jsnajdr thanks for reporting this. This seems to need a bit more investigation but maybe the removal of support for facebook embeds here: #24472 might be involved.

Also just pasting your provided url in creates a code block for me.. Do you try to insert an embed block and paste the url?

[jsnajdr]

Also just pasting your provided url in creates a code block for me..

I'm simply copy&pasting a URL from the browser URL bar. The code block is triggered by the triple-backtick Markdown formatting I used to write the URL in the issue description. Maybe you're doing some rich-text copy&paste that copies the formatting, too? That looks like a plausible way how the code block could be triggered.

[ntsekouras]

The code block is triggered by the triple-backtick Markdown formatting

Yes that was the case 👍, my bad, but it's the same as trying to create an embed block due to the embed block's transformations.

[jsnajdr]

@ntsekouras It seems to be caused by #24090 after all, namely the refactor that replaced Lodash includes( html, x ) with html.includes( x ). See the fix in #25140.

[ntsekouras]

Thanks @jsnajdr for looking into it and for the fix! I approved your fix there 💯