Warning after inserting a Gallery into an empty post

[Mamaduka]

Description

The following React warning is logged in the console after inserting a Gallery into an empty post. The gallery should be the only block in a post.

Based on the trace, this might be related to recent changes introduced for the Footnotes feature #51201.

cc @ellatrix

Warning: Each child in a list should have a unique "key" prop.

Check the top-level render call using <figure>. See https://reactjs.org/link/warning-keys for more information.
    at figure

Step-by-step reproduction instructions

1. Create a new post.
2. Insert Gallery block.
3. Select images from the media library and create a Gallery.
4. The warning should be logged in the console.

There are a few other ways to reproduce the warning. See the screencast for another one.

Screenshots, screen recording, code snippet

CleanShot.2023-07-06.at.12.53.46.mp4

Environment info

• WP 6.2, Gutenberg latest trunk
• Chrome, MacOS

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

[t-hamano]

I was able to reproduce the same issue shortly after this issue was submitted. With the latest trunk, I could not reproduce this issue. I think #52241 probably solved the problem because the getRichTextValues that appear in the trace changed in #52241.

Therefore, I would like to close this issue.