Plugin: Remove compat layers for WP 6.4 and 6.5

[Mamaduka]

What?

PR removes compat layers for WP 6.4 and 6.5. This is usually done after each release.

How?

• Remove compat files.
• Fix any errors that appear in logs.

Testing Instructions

• All CI checks are green.
• Smoke test editors and front-end view. They should work as before.
• There are no PHP warnings/errors in logs.

Testing Instructions for Keyboard

Same.

[Mamaduka]

cc @WordPress/gutenberg-core

[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.

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: Mamaduka <mamaduka@git.wordpress.org>
Co-authored-by: talldan <talldanwp@git.wordpress.org>
Co-authored-by: hellofromtonya <hellofromtonya@git.wordpress.org>
Co-authored-by: creativecoder <grantmkin@git.wordpress.org>
Co-authored-by: ramonjd <ramonopoly@git.wordpress.org>
Co-authored-by: dmsnell <dmsnell@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>

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[Mamaduka]

@hellofromtonya, do we still need this?

[hellofromtonya]

@Mamaduka no longer needed as of 6.4.0.

That callback was deprecated and its associated add_action() hook was removed in 6.4.0 via r56500.

[Mamaduka]

Thank you, @hellofromtonya!

[Mamaduka]

The remaining PHPUnit test failure comes from a test introduced in #60354. Based on the description, it seems like a back-sync from the core (WP 6.5), but I can find a similar test at https://github.com/WordPress/wordpress-develop.

cc @creativecoder

[github-actions]

Flaky tests detected in fac3b3d.
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/10168055536
📝 Reported issues:

• [Flaky Test] Navigates from items list to preview via TAB, and vice versa #62434 in /test/e2e/specs/site-editor/dataviews-list-layout-keyboard.spec.js

[dmsnell]

Much of the 6.6 HTML API code relies on the 6.5 compat layer. They will need to be updated and brought over as the _6_6 variants otherwise code will crash when those _6_5 classes are missing.

[ramonjd]

Thanks @Mamaduka!!

I've tested the features I'm most familiar with:

✅ revision REST API related functionality (lib/compat/wordpress-6.4/class-gutenberg-rest-global-styles-revisions-controller-6-4.php)
✅ date translations (lib/compat/wordpress-6.5/script-loader.php)
✅ background CSS validation (lib/compat/wordpress-6.5/kses.php)
✅ deleting draft patterns (lib/compat/wordpress-6.4/blocks.php)

[t-hamano]

Is this PR intended to drop support for WP 6.4 and WP 6.5? If so, I think the "Requires at least" field also needs to be updated to 6.6.

Otherwise, we will likely encounter critical errors in older WordPress versions.

Here is an example of the error:

Fatal error: Uncaught Error: Call to undefined function get_all_registered_block_bindings_sources() in /var/www/html/wp-content/plugins/gutenberg/lib/compat/wordpress-6.6/block-bindings/pattern-overrides.php:49
Stack trace:
#0 /var/www/html/wp-includes/class-wp-hook.php(324): gutenberg_register_block_bindings_pattern_overrides_source('')
#1 /var/www/html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array)
#2 /var/www/html/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#3 /var/www/html/wp-settings.php(643): do_action('init')
#4 /var/www/html/wp-config.php(142): require_once('/var/www/html/w...')
#5 /var/www/html/wp-load.php(50): require_once('/var/www/html/w...')
#6 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...')
#7 /var/www/html/index.php(17): require('/var/www/html/w...')
#8 {main} thrown in /var/www/html/wp-content/plugins/gutenberg/lib/compat/wordpress-6.6/block-bindings/pattern-overrides.php on line 49

Also, I remember that the Gutenberg plugin customarily supported one version older.

[ramonjd]

I think the "Requires at least" field also needs to be updated to 6.6.

Good point! I think @Mamaduka also raised previously that performance tests hashes might need an update?

https://github.com/WordPress/gutenberg/pull/56464/files#r1402992768

[talldan]

@Mamaduka Is it right that the 6.5 folder is being removed? My understanding is that Gutenberg usually supports the last two WordPress versions (current stable and previous), so that would usually mean only removing the 6.4 folder. I can't find any written confirmation of that, though! Maybe this changed at some point, and I'm not aware.

Here's a link to one of the previous times this was done - #60780

Edit - actually I think you're right, here's a couple more PRs:

• Plugin: require minimum WordPress 6.2 #53451
• Remove compatibility layer for WP 6.2 #56464

They both removed the folder for the version previous to the current release, as this PR does.

[talldan]

There's also some code in the button block that can be removed so I've pushed a commit - #63115

[t-hamano]

Can we also remove this fallback code for WP6.4?

gutenberg/lib/block-supports/layout.php

Lines 1030 to 1043 in 86735ca

	/*
	* The class_list method was only added in 6.4 so this needs a temporary fallback.
	* This fallback should be removed when the minimum supported version is 6.4.
	*/
	$classes = $processor->get_attribute( 'class' );
	if ( $classes ) {
	$classes = explode( ' ', $classes );
	foreach ( $classes as $class_name ) {
	if ( str_contains( $class_name, 'is-layout-' ) ) {
	array_push( $layout_classes, $class_name );
	$processor->remove_class( $class_name );
	}
	}
	}

[Mamaduka]

The "Requires at least" field needs to be updated to 6.5. The plugin supports the latest two major releases.

Updating the "Requires at least" field and performance hash were usually done separately.

[Mamaduka]

Here's the PR for bumping versions and perf job SHA - #64126.

[talldan]

Thanks for handling this.

I've smoke tested 6.5 and 6.6 with the build from this PR and haven't spotted any issues.

Also not seeing anything that stands out in the code, it all looks good to me. Nice job!