Auto-post a Playground preview link on every PR

[adamziel]

Similarly to wordpress-develop, the Gutenberg repo could have a preview link automatically posted at every PR.

See: How to add Pull Request previews to your repository?

Here's a GitHub action from another repo for inspiration:

https://github.com/adamziel/blueprints/blob/778ba6fad9e07cec6fa3d0803cbf589bdd5ea8b1/.github/workflows/preview-comment.yml

The Gutenberg PR previewer lives at https://playground.wordpress.net/gutenberg.html

Also, @dmsnell had this great idea:

💡 if a Gutenberg PR contains Depends on WordPress/wordpress-develop#5379 then the Playground comment includes a link drawing in both the Gutenberg and Core PRs

Implementing Dennis's idea would also require adjusting gutenberg.html

CC @ockham @jsnajdr @ellatrix – anyone interested in adding this integration?

[talldan]

I think this duplicates #60433.

I love the idea, but at the same time there are a lot of bot comments on PRs right now which creates a lot of notification noise, and it'd be great if they could be consolidated. Perhaps some of these workflows can be combined into a single comment where only portions of the comment are updated.

[adamziel]

Aha! Or it could update the PR description and add the button/link at the bottom to save some vertical space :)

[talldan]

I was thinking that you may not even need a bot if there were a way to include the PR number as a templated part of the pull request template -
https://github.com/WordPress/gutenberg/blob/trunk/.github/PULL_REQUEST_TEMPLATE.md.

(granted that the PR may not always be ready to preview, but maybe that would be an acceptable trade-off)

Unfortunately I don't think it's possible having had a quick look through the docs - https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/about-issue-and-pull-request-templates.

[adamziel]

Ooh that would have saved so much effort, too bad GitHub doesn't support that indeed!

[adamziel]

@vcanales created a reusable GitHub action here: https://github.com/vcanales/action-wp-playground-pr-preview/ 🎉 I'm filing a few issues to make it configurable enough to reuse everywhere.

[carstingaxion]

Because I did a similar workflow for the GatherPress plugin, @paaljoachim motivated me on slack to do the same for Gutenberg. And I’m willing to do so.

The action by @vcanales, mentioned by @adamziel, seems to be relevant and easy for a theme, but not a plugin.

Anything I need to know?

I’m starting working on this now.

[carstingaxion]

I opened a PR, which was kinda fun as it got much smaller than expected, because Gutenberg has so many of the necessary parts already on board.

I didn't need to worry about a suitable plugin-proxy.php, there was need for an additional build step and the whole built plugin got uploaded as GitHub artifact already. Cool!

So the only thing missing was a script that comments an updated link to a Playground. And that is what I did in #64947 .

Please have a look, everybody and add your appreciated feedback.