'Freeform' block is not supported error appears in between a custom post type's template blocks

[skorasaurus]

Description

After the introduction of #52325,

I'm running into a unique case specifically: when editing already published custom posts whose content is inserted through the register_post_type($template), A block warning appears in the editor stating 'Your site doesn’t include support for the "core/freeform" block. You can leave this block intact or remove it entirely.'

As far as I know, the block content I have inserted into the custom post type is valid and does not contain a classic block.

Notably, I am unable to reproduce this in Gutenberg 16.2.1;

Step-by-step reproduction instructions

1. Install Gutenberg nightly from or update your current branch to trunk (and build)
   2a. Go to Experiments http://yoursite.test/wp-admin/admin.php?page=gutenberg-experiments.
   2b. Enable the "Disable TinyMCE and Classic block" experiment and click "Save Changes".
2. Install and activate the test case plugin - (https://gitlab.com/cpl/test-case-52811)
3. create new 'agenda' (the new custom post type);
4. publish the post
5. refresh the editor in your browser

Screenshots, screen recording, code snippet

2023-07-20-gutenberg.mp4

Environment info

WP 6.2; Gutenberg built from trunk 2023-07-18 or newer. Have been able to reproduce with and without classic editor plugin installed.

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

yes (except the test case plugin)

[Mamaduka]

Cc @tyxla

[tyxla]

Thank you @Mamaduka for the ping and @skorasaurus for the thorough report!

I'll work on a fix this week.

[tyxla]

Alright, I've got a few related and direct fixes of this one - could use some 👀 if you folks have a chance:

• Block Library: Set freeform handler only if Classic block exists #52936 - sets the freeform content handler only if the block exists, part of the fix for this issue.
• Block Library: Do not display empty classic blocks if Classic block is not registered #52937 - stops displaying missing blocks for empty freeform blocks if that block is not registered.
• Experimental: Backend handle freeform blocks with TinyMCE removal #52938 - handles existing core/freeform blocks in post content properly
• Experimental: Fix TinyMCE removal for heartbeat requests #52935 - resolves some warning during heartbeat XHR requests and on the page to create a post from custom post types

Let me know what you think!

[tyxla]

@skorasaurus now that we merged #52935 and #52936, would you mind giving this a try with the latest trunk?

We still have #52938 open, but that resolves a different scenario, so you should be good when testing with the above steps. Actually, this landed as well already.

Let me know how it goes, thanks 🙌

[skorasaurus]

Thank you again for your work @tyxla and @Mamaduka (and anyone who reviewed the PRs).

Using the latest trunk, I am unable to reproduce the issue described earlier. I tested using my reduced test-case plugin and in another plugin that I maintain that has more complex blocks in the custom post template.

I edited and updated some other classic blocks on other pages on my site(s), and they worked as expected as well.

[tyxla]

Good to hear! 🎉

Thanks for confirming @skorasaurus and once more, thank you for testing the TinyMCE deprecation experiment 🙌