Global Styles: Preserve block style variations in global styles revisions.

[ramonjd]

Description

Fixes an issue where block style variations were being stripped from global styles revisions when retrieved via the REST API.

Trac ticket: https://core.trac.wordpress.org/ticket/64292

Problem

When retrieving global styles revisions through the REST API, any block style variations (e.g., styles.blocks.core/group.variations.my-variation) were being removed during WP_Theme_JSON sanitization. This occurred because:

1. WP_Theme_JSON::sanitize() only preserves variations that exist in $valid_variations
2. $valid_variations is populated from WP_Block_Styles_Registry (registered block styles)
3. The revisions controller wasn't registering theme-defined variations before instantiation
4. Unregistered variations were stripped by remove_keys_not_in_schema()

Why This Matters

• Gutenberg works, Core doesn't: Gutenberg registers variations late through WP_Theme_JSON_Resolver_Gutenberg::get_merged_data()
• Data loss: Revision history was losing block style variation data
• Inconsistent behavior: Different outcomes depending on request lifecycle/initialization order

Solution

Register theme-defined block style variations in WP_REST_Global_Styles_Revisions_Controller::prepare_item_for_response() before instantiating WP_Theme_JSON, ensuring variations pass sanitization regardless of initialization order.

Changed file: src/wp-includes/rest-api/endpoints/class-wp-rest-global-styles-revisions-controller.php

Testing Instructions

Switch to a theme with block style variations (e.g., Twenty Twenty-Five)

Go to Global styles > Group and select a style variation

Change the style variation and save. Create a few revisions.

In the site editor, apply the variation to a group block and save the post.

Now open the global styles > revisions and ensure that, when you click on a past revision the style variation applies to the group block.

Kapture.2025-11-23.at.18.28.40.mp4

You can also check that the REST API returns the full revisions:

await wp.data.resolveSelect( 'core' ).getRevisions( 'root', 'globalStyles', await wp.data.resolveSelect( 'core' ).__experimentalGetCurrentGlobalStylesId() )

Run the test suite for bonus points

npm run test:php -- --filter=WP_REST_Global_Styles_Revisions_Controller_Test

Props

@ellatrix for finding the bug in WordPress/gutenberg#73440 and @aaronrobertshaw for initial investigation

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Props ramonopoly, aaronrobertshaw, ellatrix.

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[aaronrobertshaw]

Thanks for the fast work on this fix @ramonjd 🙇

It's testing well for me. I have one tiny nit regarding the inline comment but other than that, it LGTM.

✅ Manual testing via site editor, creating revisions with variations data, applying them etc all works

Screen.Recording.2025-11-24.at.5.28.53.pm.mp4

✅ API response contains correct variations styles data

✅ Automated test coverage looks good and all passes locally

[ellatrix]

Do you know when it was introduced?

[ramonjd]

Do you know when it was introduced?

Style variations have been a thing since May/June 2024. See:

• Global Styles and Theme.json: Next Steps gutenberg#62686

First added to Core in f91931a

[ramonjd]

Thanks for testing @aaronrobertshaw 🙇🏻

[ramonjd]

Committed in https://core.trac.wordpress.org/changeset/61301