Read only once the theme.json files from the styles/ folder.

[oandregal]

Trac ticket https://core.trac.wordpress.org/ticket/61451

What

Read only once the theme.json files stored in the styles/ folder.

Why

I've realized that, unlike the theme.json files defined by core & theme, we don't cache these — hence we end up reading them a few times from the filesystem.

How

By using the existing read_json_file function instead of using wp_json_file_decode directly.

How to test

1. Verify the theme style variations are working as expected.

Go to "Site Editor > Styles" and apply one of them. Verify the changes are reflected in the front end. Do the same from the global styles sidebar in the site editor.

2. Verify the block style variations defined via theme.json are working as expected.

Create a partial.json file within the styles/ folder with the following contents:

{
        "$schema": "https://schemas.wp.org/trunk/theme.json",
        "version": 2,
        "title": "Partial",
        "blockTypes": [ "core/group" ],
        "styles": {
                "color": {
                        "background": "aliceblue"
                }
        }
}

Go to any editor, add a group block, and verify there is a "Partial" style variation (Block Settings > Styles). Apply the variation and save the changes. Verify the contents are the expected (background color is aliceblue) — also in the front-end.

Commit

Commit message, to make it easy for committers:

Read only once the theme.json files stored in the `styles/` folder.

Props oandregal, aaronrobertshaw, joemcgill, ramonopoly, isabel_brison.
See #61451.

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Props oandregal, aaronrobertshaw, joemcgill, ramonopoly, isabel_brison.

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[joemcgill]

Definitely a good idea to avoid rereading these same files. I wonder if we can also avoid the potential of processing the same decoded files multiple times as well?

[aaronrobertshaw]

I wonder if we can also avoid the potential of processing the same decoded files multiple times as well?

This PR was an initial step given issues encountered in an original attempt to also cache the additional processing of those files in: WordPress/gutenberg#62610

[ramonjd]

Tested and LGTM

Gutenberg sync PR over here:

• Theme JSON resolver: read theme.json files from the styles/ folder only once gutenberg#62638

[ramonjd]

I wonder if we can also avoid the potential of processing the same decoded files multiple times as well?

Very good question! I'll keep that in mind when testing WordPress/gutenberg#62638, maybe there's an way to test in the plugin first.

[aaronrobertshaw]

LGTM 👍

✅ Theme style variations continue to work
✅ Block style variations are registered from partials correctly

Screen.Recording.2024-06-18.at.2.39.11.PM.mp4

Might be worth adding a note about the caching to the @since comment?

[aaronrobertshaw]

Might be worth adding a note about the caching to the @SInCE comment?

I've taken then liberty to push this minor tweak.

[tellthemachines]

Just gave this a test run and switching styles and variations works as expected!

[tellthemachines]

committed in r58428.