Iconpicker does not render classes appropriately

I suspect this might be due to old data already being saved. If you change the icon to a new one, does it render properly (with the new prefixes)?

During testing, I made sure to test on a new page and inserted a new icon ("fa-house") which resulted in <i class="fa-fas fa-house"></i> being printed.

This is strange, I can't reproduce. Are you inserting with an actual icon field, or are you using the CKEditor button?

This is from inserting using the actual icon field.

When I inspect the select dropdown, all the values are still "fas", "fab", etc. Are they supposed to be showing "solid" and "brands"?

I tracked this down. The iconpicker submodule does not render classes appropriately (has not been updated to use the new fa-solid prefix rather than fas).

Attaching patch - please confirm this fixes your issue

The provided patch does not fix anything. When using the provided field widget only (not the submodules at all), the classes for the icons in the autocomplete do not match FontAwesome 5 classes. They do however match FontAwesome 6.

Take for example the `drupal` icon: Using FA5 the appropriate classes are 'fab fa-drupal'. But in the autocomplete controller, the brands are prefixed with 'fa-brands'. This matches the FA6 version of the "drupal" icon though.

The good thing for me is that the displayed classes using the included field widget render correctly.

I do believe this module should definitely support the FA6 classes, but also the FA5 classes.

I believe I found the issue - I've attached my current patch as a starting point, but it doesn't take into consideration other work or changes that might exist in other areas of the module - and also ignores FA5 compatibility.

Mostly, the issue (in the latest 8.x-2.x branch) is at line 639 in src/Plugin/Field/FieldWidget/FontAwesomeIconWidget.php. This seems to prepend the selected icon style with fa- which is giving us the incorrect class(es) on the icon when printed. Related: the available options are on line 119, but the following lines of code seem to be removing styles without checking if their Sharp alternatives are still enabled.

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Since the module is prepending fa- it either needs to change the available style values to the words of the styles (e.g. 'solid' instead of 'fas') or remove the prepending functionality on line 639. Either way, we could check to see which value is added, and simply add the _additional_ class for the previous or next version.

Example: If the module implements the full word option, then if the value is set to 'solid', prepend fa- and then append fas.

This would make it work for both FA5 and FA6, I think.