[nlemoine]

enqueue_assets_for_post() passes 'defer' => true in the $args array of wp_enqueue_script(). That key has never been supported, so the script was never actually deferred. Since WordPress 7.0, unknown keys also trigger a _doing_it_wrong() notice on every block editor load:

wp_enqueue_script was called incorrectly. Unrecognized key(s) in the $args param: defer. Supported keys: strategy, in_footer, fetchpriority, module_dependencies (This message was added in version 7.0.0.)

This switches to 'strategy' => 'defer', available since WordPress 6.3. The script only calls registerPlugin(), and deferred scripts run before DOMContentLoaded, so before the editor is initialised.

Tests enqueue the editor assets and check that no incorrect usage notice is raised and that the printed script tag has the defer attribute. The PHPUnit workflow doesn't build the JS, so the test creates a minimal build/index.asset.php when it is missing and removes it afterwards. Both tests fail against the previous code on WP 7.1, and the deferred check fails on WP 6.9 if the key is removed.

[roborourke]

If the intention was always to defer it (and note there might have been some other code in a project or elsewhere making use of this arg overload) then it'd be good to check it works with that fix and to defer through the proper WP system, rather than ignore it altogether.

A PHP test is probably overkill for this change, but it doesn't hurt :)

[nlemoine]

Good point, the intention was clearly to defer it. Switched to 'strategy' => 'defer', and the test now checks that the printed script tag has the defer attribute (it fails on both 6.9 and 7.1 without the key). The script only calls registerPlugin(), so deferring it doesn't change anything for the editor init.