Theme JSON: Check for null values to cater for blockGap

[ramonjd]

What?

I noticed this PHP error while trying to extract block styles, whose values have a CSS var, using wp|gutenberg_get_global_styles().

Deprecated: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in lib/class-wp-theme-json-gutenberg.php on line 3827

Deprecated: preg_match_all(): Passing null to parameter #2 ($subject) of type string is deprecated in lib/class-wp-theme-json-gutenberg.php on line 3830

It's complaining about passing a null value to strpos() in WP_Theme_JSON_Gutenberg::convert_variables_to_value

So I added a check to make sure the value is not empty before we run it through strpos().

Why

When using wp|gutenberg_get_global_styles() with the resolve-variables flag like this —

`gutenberg_get_global_styles( array( 'typography', 'fontSize' ), array( 'block_name' => 'core/search', 'transforms' => array( 'resolve-variables' ) ) );`

— it will grab merged Theme JSON data from WP_Theme_JSON_Resolver_Gutenberg::get_merged_data() and run it through WP_Theme_JSON_Gutenberg::resolve_variables, which calls self::convert_variables_to_value.

The snag is that:

1. WP_Theme_JSON_Resolver_Gutenberg::get_merged_data() calls static::get_block_data()
2. static::get_block_data() sets blockGap for supported blocks to null if the value is not defined.

Because WP_Theme_JSON_Gutenberg::convert_variables_to_value is expecting strings as values, it will trigger the error.

Testing Instructions

Run the tests: npm run test:unit:php:base -- --filter WP_Theme_JSON_Gutenberg_Test

If you like, try to call the function from inside a block render/block supports function, or anywhere you're sure that block styles have already been registered

$test = gutenberg_get_global_styles( array( 'spacing', 'blockGap' ), array( 'origin' => 'base', 'block_name' => 'core/post-template', 'transforms' => array( 'resolve-variables' ) ) );
var_dump($test);

You should see NULL and no errors.

[github-actions]

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Co-authored-by: ramonjd <ramonopoly@git.wordpress.org>
Co-authored-by: andrewserong <andrewserong@git.wordpress.org>

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[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/class-wp-theme-json-gutenberg.php
❔ phpunit/class-wp-theme-json-test.php

[ramonjd]

i added this test to check the happy path, e.g., resolution of spacing presets when those presets are applied to blockGap values.

[github-actions]

Flaky tests detected in ece1a4d.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/7999294851
📝 Reported issues:

• [Flaky Test] list view should correctly reflect navigation items' structure #58980 in /test/e2e/specs/editor/blocks/navigation-list-view.spec.js

[andrewserong]

Thanks for fixing this up!

I didn't see the warning at first because my local env was running an older PHP version (PHP 8.0.22), but after updating to 8.2.10, I could see the PHP Deprecated warnings:

With this PR applied, no warnings 👍

LGTM! ✨

[getdave]

@ramonjd Do you want to backport this to WP 6.5? If so please can you add the requisite labels? Many thanks.

[ramonjd]

Do you want to backport this to WP 6.5? If so please can you add the requisite labels? Many thanks.

This will require a PHP back port.

I was going to prep one today.

I'm not sure it'll make 6.5, but I'll label the trac ticket to try 😄

[getdave]

I noticed the backport isn't committed. I'm going to try and wrangle this in time for Beta 3 today.

Perhaps @swissspidy or @youknowriad can commit as I don't have permissions.