Gallery Block: Media Library not refreshing after adding local files to existing Gallery

[mrfoxtalbot]

@pauljacobson and I tested edits to a Tiled Gallery block on both a WordPress.com site, and a self-hosted WordPress.org site. We noticed an issue that occurred when editing a Tiled Gallery in a Gutenberg block.

Steps to reproduce

1. Starting with a Tiled Gallery added to a post, working in the WP Admin dashboard.
2. Clicked on the pencil icon to edit an existing mosaic gallery in a Tiled Gallery block.
3. Uploaded a new image to add to the gallery.
4. The new image was initially numbered as an addition to the gallery, and was then immediately unselected.
5. After selecting the new image, we added it to the gallery.
6. We then saved the post, and clicked on the pencil icon again to add another image.
7. When the Media browser opened, it didn't include the previous addition, despite it appearing in the revised gallery.
8. The addition to the gallery only appeared in the Media browser when we reloaded our browser tab.

What I expected

When uploading a new image, and adding it to an existing gallery in a Tiled Gallery block, the Media browser should update to reflect current contents of the gallery when invoking it. This is the default behaviour both in the wp-admin classic editor and in the classic block.

What happened instead

Instead, despite adding a new image to the gallery, the Media browser does not update to reflect the contents of the updated gallery, at least not until the browser tab is reloaded.

Browser / OS version

Firefox Developer Edition, v66.0b4 running on macOS 10.14.2

This issue was reproduced using gallery blocks on both WordPress.com and a self-hosted site. We were also able to reproduce this on Calypso.

Screenshot / Video

Here's a higher resolution video version of this GIF demonstrating of the issue

Context / Source

Internal testing in Automattic by @mrfoxtalbot and @pauljacobson

[simison]

Noting that Tiled gallery block is a Jetpack block.

We have a couple of issues open related to this at our end:
Automattic/wp-calypso#28959
https://github.com/Automattic/wp-calypso/issues/30065

That said, this is also an issue in the core Gallery block and probably in other image related blocks as well. So block names in the original description could be switched and this would still be a valid report.

This is fixed in #12435 and reported originally in #9073

[mrfoxtalbot]

Thank you, I looked up only issues but I will make sure to check PRs next time.

[simison]

This is now fixed as of #12435 and can be closed.