A Customised fixer for PHP-CS-Fixer to use `prettier`'s php plugin to pre-process the code before getting analysed by other fixers. This would enable `php-cs-fixer` to take advantage of `prettier`'s ability of managing long line.

.php_cs.dist

<?php

require_once __DIR__.'/PrettierPHPFixer.php';

$finder = PhpCsFixer\Finder::create()
    ->exclude('somedir')
    ->notPath('src/Symfony/Component/Translation/Tests/fixtures/resources.php')
    ->in(__DIR__)
;

return PhpCsFixer\Config::create()
    ->registerCustomFixers([
        (new PrettierPHPFixer()),
    ])
    ->setRules([
        'Prettier/php' => true,
        '@PSR2' => true,
    ])
    ->setFinder($finder);

PrettierPHPFixer.php

<?php

use PhpCsFixer\Fixer\FixerInterface;
use PhpCsFixer\Tokenizer\Tokens;
use Symfony\Component\Filesystem\Filesystem;

/**
 * Fixer for using prettier-php to fix.
 */
final class PrettierPHPFixer implements FixerInterface
{
    /**
     * {@inheritdoc}
     */
    public function getPriority()
    {
        // should be absolute first
        return 999;
    }

    /**
     * {@inheritdoc}
     */
    public function isCandidate(Tokens $tokens)
    {
        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function isRisky()
    {
        return false;
    }

    /**
     * {@inheritdoc}
     */
    public function fix(SplFileInfo $file, Tokens $tokens)
    {
        if (
            0 < $tokens->count() &&
            $this->isCandidate($tokens) &&
            $this->supports($file)
        ) {
            $this->applyFix($file, $tokens);
        }
    }

    /**
     * {@inheritdoc}
     */
    public function getName()
    {
        return 'Prettier/php';
    }

    /**
     * {@inheritdoc}
     */
    public function supports(SplFileInfo $file)
    {
        return true;
    }

    /**
     * {@inheritdoc}
     */
    private function applyFix(SplFileInfo $file, Tokens $tokens)
    {
        $tmpFile = $this->getTmpFile($file);
        // If you want to give custom config (though if you name it prettierrc, it automatically uses it)
        // $configFile = __DIR__ . '/.prettierrc';
        // system("prettier --write --config {$configFile} $tmpFile");
        // system command as I have installed prettier and exec was not working.
        system("prettier --write $tmpFile");

        $content = file_get_contents($tmpFile);
        $tokens->setCode($content);

        (new Filesystem())->remove($tmpFile);
    }

    /**
     * Create a Temp file with the same content as given file.
     *
     * @param SplFileInfo $file file to be copied
     *
     * @return string tmp file name
     */
    private function getTmpFile(SplFileInfo $file): string
    {
        $fileSys = new Filesystem();
        $tmpFolderPath = __DIR__ . '/tmp';
        $fileSys->mkdir($tmpFolderPath);

        $tmpFileName = str_replace(
            DIRECTORY_SEPARATOR,
            '_',
            $file->getRealPath()
        );
        // add php extension to enable prettier php plugin.
        $tmpFilePath = $tmpFolderPath . '/__' . $tmpFileName . '.php';
        $fileSys->copy($file->getRealPath(), $tmpFilePath, true);
        return $tmpFilePath;
    }
}

I had installed prettier and prettier php plugin globally using npm. I did not know how to exec using npm and alse php exec was not working so I used system function. Also this php plugin only works on the .php extension, so it was actually not formatting the temp file. Hence I appended php extension.