Preload: fix multiple regressions around global styles

[ellatrix]

A PR to track the backporting of WordPress/gutenberg#66468

This fixes a regression whereby requests to global styles endpoints were not being preloaded, resulting in several requests being fired clientside unnecessarily.

For performance reasons, we should preload the requests so that the data is in the store and ready to use straight away.

The outcome is that the editor loads more quickly.

Testing

Fire up this branch and head to the site editor.

Check that global-styles endpoints aren't fetched client side, but are, rather, preloaded via rest_preload_api_request

Do the same for the post editor.

Trac ticket: https://core.trac.wordpress.org/ticket/62315

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[apermo]

Besides my comment, that I'm unsure about naming of the variable, this looks technically solid and fine.

👍

[ramonjd]

I tested this using the plugin (to get the js packages) and reverting the PHP changes in WordPress/gutenberg#66468

Looks good in both the site and post editors - the requests cited in WordPress/gutenberg#66468 are now prefetched by rest_preload_api_request

"/wp/v2/global-styles/themes/twentytwentyfive?context=view"
"/wp/v2/global-styles/themes/twentytwentyfive/variations?context=view"
"/wp/v2/global-styles/5"
"/wp/v2/global-styles/5?context=edit"

[ramonjd]

I added some missing commas, which were crashing things, but LGTM

[peterwilsoncc]

Was this regression introduced during the 6.7 cycle?

[ramonjd]

Was this regression introduced during the 6.7 cycle?

Yes. Not too late to update?

[peterwilsoncc]

@ramonjd in cycle regressions can still be fixed, so it's not too late.

[ramonjd]

Depending on user capabilities, a different clientside request will fire, e.g.,

✅ user can update global styles: '/wp/v2/global-styles/' . WP_Theme_JSON_Resolver::get_user_global_styles_post_id() . '?context=edit',

🔕 user cannot update global styles: '/wp/v2/global-styles/' . WP_Theme_JSON_Resolver::get_user_global_styles_post_id() . '?context=view',

So at the moment, editors will get a clientside request since '?context=view', isn't preloaded.

I'm wondering if it's worth changing this to "view" context based on caps.

Probably for a follow up, as this already fixes a bunch of unnecessary requests.

[ramonjd]

I've tried that here just to test things out:

• Global styles: preload user global styles based on user caps gutenberg#66541

[ramonjd]

WordPress/gutenberg#66468 has been cherry picked to Gutenberg's wp/6.7 branch

[ramonjd]

Do we need a second committer review to get this in the next 6.7 RC?

[peterwilsoncc]

@ramonjd The trunk commit can be on your approval, then re-open the trac ticket and add the dev-feedback keyword to put it in the queue for a second committer to review for backport.

[ramonjd]

Committed in r59316 / dc4bd050