Symfony version(s) affected: 3.4.18

Description

When extracting metadata about properties, the reflection extractor fails to recognize setters/getters for class properties that have snake_case.

\Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor
getMutatorMethod() and getAccessorMethod() have the same logic:

$ucProperty = ucfirst($property);

According to PSR-1, there is no restriction about property names - they intentionally omit any provisions whether to use SturdlyCase, camelCase or snake_case.

At the same time, PSR-1 states that methods must be in camelCase.

How to reproduce

<?php
use Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor;

require __DIR__ . '/vendor/autoload.php';

class MyEntity
{
    /** @var \DateTime */
    private $foo_bar;

    public function getFooBar(): DateTime
    {
        return $this->foo_bar;
    }

    public function setFooBar(DateTime $value): void
    {
        $this->foo_bar = $value;
    }
}

$extractor = new ReflectionExtractor();
$extractor->getTypes('MyEntity', 'foo_bar');
// returns null
// attempts setFoo_bar()

Possible Solution

For best compatibility with PSR-1, the extractor should attempt methods that do not contain "_".
E.g. in addition to "setFoo_bar", it should also attempt "setFooBar" (or "setfoobar" - in PHP, method names are not case-sensitive)