Always output core block global styles after base global styles

[tellthemachines]

What?

Brings the changes from WordPress/wordpress-develop#6010 into Gutenberg.

When should_load_separate_core_block_assets is true, core block global styles should now be loaded right after base global styles, inside the global-styles-inline-css tag. This matches the loading order when should_load_separate_core_block_assets is false, as well as the order inside the editor iframe.

When should_load_separate_core_block_assets is true, only the styles relevant to the blocks on the page should be loaded.

Testing Instructions

1. Publish a post with a Quote or a Button block and one without. Make sure the post template itself doesn't contain these blocks.
2. In the front end, check that for the post with the Quote, quote global styles are loaded, but for the post without the Quote they aren't.
3. Check that the block global styles are loaded after the base global styles (this can be easily checked by e.g. adding a background color to the Button block in global styles, and checking that style is output after the base global styles default button background color)

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core SVN

Core Committers: Use this line as a base for the props when committing in SVN:

Props isabel_brison, poena, oandregal.

GitHub Merge commits

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: tellthemachines <isabel_brison@git.wordpress.org>
Co-authored-by: carolinan <poena@git.wordpress.org>
Co-authored-by: oandregal <oandregal@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[github-actions]

This pull request has changed or added PHP files. Please confirm whether these changes need to be synced to WordPress Core, and therefore featured in the next release of WordPress.

If so, it is recommended to create a new Trac ticket and submit a pull request to the WordPress Core Github repository soon after this pull request is merged.

If you're unsure, you can always ask for help in the #core-editor channel in WordPress Slack.

Thank you! ❤️

View changed files

❔ lib/global-styles-and-settings.php

[carolinan]

I have tested the PR manually and it works as described.

[oandregal]

Thanks for making sure both codebases are in sync.