Improve Drupal\Core\Ajax\AddCssCommand to accept an array of CSS assets

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Did a rebase & squash, since merge conflicts were pretty significant, and addressed remaining comments.

I changed the jQuery Deferred to a native Promise, matching add_js. I'm still not sure that it is actually necessary - there isn't a concern about out-of-order execution like with new JS files that was the reason for introducing the add_js command.

Tests are now passing, and I've updated the draft Change Record

It looks nice and ready except legacy test for JS deprecation message

Added a test for a the JavaScript deprecation message

Thanks 👍 last mossing brick is follow-up to remove deprecation in 11.x - todo needs link to issue

Filed follow-up 📌 [11.x] Require array argument for AddCssCommand Postponed fixed TODOs https://git.drupalcode.org/project/drupal/-/merge_requests/1420/diffs?co...

Change record makes sense (to me)
Test coverage of deprecation is there
New tests for new way to do the call is there
No remaining tasks
All remaining threads closed

This looks good to me.

updated release notes.

I was about to commit this but have a question, with this change it's not possible to add inline CSS with the addCss command. It's easy enough to add a new append/prepend command with the styles to do the same but just wondering if we're all good with that.

Let's move forward and fix if/when necessary

Committed 8496c2c and pushed to 10.1.x. Thanks!

nod_ → closed merge request !1420

Very nice!

Automatically closed - issue fixed for 2 weeks with no activity.

This introduced a fairly convoluted regression 🐛 claro.jquery.ui css assets may be added the page multiple times Fixed

I was about to commit this but have a question, with this change it's not possible to add inline CSS with the addCss command. It's easy enough to add a new append/prepend command with the styles to do the same but just wondering if we're all good with that.

This broke the Critical CSS module: 🐛 Critical CSS is broken in AJAX requests since Drupal 10.1.0 Active

Previous behavior was to prepend the CSS:
$('head').prepend(response.data);

I think the new code is appending to which can cause order of precedence issues. A module might have CSS component assets (weight of 0) which are added into after our theme's CSS_THEME assets (weight of 200).

This might not be an issue for most situation, but I just noticed it with some quick D10 testing in advance of an upgrade. Maybe it was just a coincidence that we were able to have our theme CSS override the module's component CSS?

Any known workarounds for this (potential) issue?

We are experiencing an issue with z-index in the media library widget related to this CSS sorting change.

It seems that https://www.drupal.org/project/drupal/issues/3396505 🐛 Improved Drupal\Core\Ajax\AddCssCommand causes change in CSS load order. Needs work fixes our issue.

Hope this helps.

We also have a problem with the z-index and the media-library-widget. It occurred after the update from 10.1.7 to 10.2.0.