[LiveForm] Required select with placeholder of TranslatableMessage has first value set upon rerender

[stehled]

The bug:
While having a liveform with required select and placeholder of type TranslatableMessage, instead of leaving this value blank, first not null value from choices is retrieved instead.

This behaviour occurs because of code in Symfony\UX\LiveComponent\ComponentWithFormTrait in if on line 276.

ux/src/LiveComponent/src/ComponentWithFormTrait.php

Line 276 in 314ca71

if (

.

In this if, the last condition is !\is_string($child->vars['placeholder']) which unfortunately is not satisfied e.g. for option 'placeholder' => new TranslatableMessage('some.value').

Solution
I would suggest to extending this condition to (!\is_string($child->vars['placeholder']) && !$child->vars['placeholder'] instanceof TranslatableMessage) or making it only !isset($child->vars['placeholder']) to support more cases. I feel that string only restriction is to harsh when most of the time, we will be creating multilingual applications.

We use TranslatableMessage class for translatable strings so our extractor can generate .yaml files with translations.

[smnandre]

I would suggest to extending this condition to (!\is_string($child->vars['placeholder']) && !$child->vars['placeholder'] instanceof TranslatableMessage)

Would you like to open a PR ?

or making it only !isset($child->vars['placeholder']) to support more cases

Any example of such case ?

[stehled]

Hi, thanks for reply, I will create PR tomorrow.

I was not able to think of any other case, therefore I will use the first suggested solution.

Thank you