Avoid PossiblyUnusedMethod on entity's setters when entity is bound to a form

[ThomasLandauer]

Psalm is reporting:

ERROR: PossiblyUnusedMethod - src/Entity/Foo.php:759:21 - Cannot find any calls to method App\Entity\Foo::setBar

...even though I have a Symfony form which is bound to Foo, and contains a field bar.

[zmitic]

It is not what you asked for, but I would still recommend to use either the default callbacks, or much better rich-forms-bundle:

'write_property_path' => fn (Foo $foo, string $bar) => $foo->setBar($bar),

If you use stricter scalars like non-empty-string, then you could even do:

'write_property_path' => function (Foo $foo, string $bar) {
    if ('' === $bar) {
        // this exception turns into validation error
        throw new TransformationFailedException(invalidMessage: 'Empty string not allowed');
    }
    // psalm now knows $bar is non-empty-string here
    $foo->setBar($bar); 
}

If you install webmozart/assert, do this first:

class FormAssert extends Assert
{
    /**
     * @psalm-external-mutation-free
     */
    protected static function reportInvalidArgument($message)
    {
        throw new TransformationFailedException(invalidMessage: $message);
    }
}

and the above code becomes:

'write_property_path' => function (Foo $foo, string $bar) {
    FormAssert::stringNotEmpty($bar);
    $foo->setBar($bar); 
}

It can be PITA to write these, but you get ctrl+click navigation to where getter/setter are used. And if any typehint is wrong, like some data transformer goes unexpected, then you will get validation error instead of 500.