Description

This report originates from Automattic/wp-calypso#94184

There are two issues here:

Adding an HTML code that code that contains the

---

code results in an eventually broken block. Block recovery attempts recovers what's before the

---

tag but not what's after it.

If using classic revisions (wp-admin). If a revision contains that

---

tag, all the content will be visible in the revisions view but anything under the tag will not be included in the restored version.

Step-by-step reproduction instructions

Using Gutenberg, on any post.
Add a paragraph block and write anything - "Test"
Edit the paragraph block as HTML and add an

---

to the end or anywhere on the paragraph, but inside the

followed by some text.
Click Edit visually.
You will get an Attempt Block Recovery button
Clicking it removes the

---

tag and all that's after it

Screenshots, screen recording, code snippet

https://d.pr/v/SbGOoZ (for some reason I can't embed this here)

Environment info

• WordPress 6.6.2
• Gutenberg 19.5.0

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

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure