[4.1][Bug] Relationship with InlineCreate allows_null not working due to missing empty option placeholder

[warton]

Bug report

What I did

I set my relationship field to allow inline_create and 'allows_null' => true

What I expected to happen

When my relationship field is set, I cannot unset it as the underlying select is missing empty option as required https://select2.org/placeholders:

For single selects only, in order for the placeholder value to appear, you must have a blank <option> as the first option in your <select> control. This is because the browser tries to select the first option by default. If your first option were non-empty, the browser would display this instead of the placeholder

What happened

My set value remained populated and didn't unset.

What I've already tried to fix it

The fix is easy for me. I've added to blade: crud/fields/relationship/fetch_or_create.blade.php:115

{{-- allow clear --}}
    @if ($field['allows_null'])
        <option value="" selected>
            {{ $field['placeholder'] }}
        </option>
    @endif

I didn't try fetch.blade.php, but I suppose it's the same issue there.

Backpack, Laravel, PHP, DB version

When I run php artisan backpack:version the output is:

PHP VERSION:

PHP 7.4.4 (cli) (built: Mar 17 2020 13:49:19) ( ZTS Visual C++ 2017 x64 )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
with Xdebug v2.8.1, Copyright (c) 2002-2019, by Derick Rethans

LARAVEL VERSION:

v7.9.2@757b155658ae6da429065ba8f22242fe599824f7

BACKPACK VERSION:

4.1.x-dev@71cff08a82f925f014e815d2daa9190b6f2e5f5f

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[pxpm]

@warton Thank you very much for spotting and providing a solution.

I'v just submited PR: #2765

As soon as it gets merged a composer update should provide you with the fix.

Also note that multiple selects does not need the empty placeholder. From select2 docs:

For single selects only, in order for the placeholder value to appear, you must have a blank

and fetch_and_create and fetch handle both multiple and non-multiple, so I updated your fix with that information in mind.

Going to close this, any further addressing should be done in the PR thread.

Thanks again @warton

[warton]

cool, thx :)

[tabacitu]

Merged! A composer update backpack/crud should do it for you @warton

[warton]

Yes, it works as expected. Thank you guys, you're the best! :)