^^&&^^

Edit File: YamlReferenceDumper.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Config\Definition\Dumper;

use Symfony\Component\Config\Definition\ArrayNode;
use Symfony\Component\Config\Definition\ConfigurationInterface;
use Symfony\Component\Config\Definition\EnumNode;
use Symfony\Component\Config\Definition\NodeInterface;
use Symfony\Component\Config\Definition\PrototypedArrayNode;
use Symfony\Component\Config\Definition\ScalarNode;
use Symfony\Component\Config\Definition\VariableNode;
use Symfony\Component\Yaml\Inline;

/**
 * Dumps a Yaml reference configuration for the given configuration/node instance.
 *
 * @author Kevin Bond <kevinbond@gmail.com>
 */
class YamlReferenceDumper
{
    private $reference;

public function dump(ConfigurationInterface $configuration)
    {
        return $this->dumpNode($configuration->getConfigTreeBuilder()->buildTree());
    }

public function dumpAtPath(ConfigurationInterface $configuration, $path)
    {
        $rootNode = $node = $configuration->getConfigTreeBuilder()->buildTree();

foreach (explode('.', $path) as $step) {
            if (!$node instanceof ArrayNode) {
                throw new \UnexpectedValueException(sprintf('Unable to find node at path "%s.%s".', $rootNode->getName(), $path));
            }

/** @var NodeInterface[] $children */
            $children = $node instanceof PrototypedArrayNode ? $this->getPrototypeChildren($node) : $node->getChildren();

foreach ($children as $child) {
                if ($child->getName() === $step) {
                    $node = $child;

continue 2;
                }
            }

throw new \UnexpectedValueException(sprintf('Unable to find node at path "%s.%s".', $rootNode->getName(), $path));
        }

return $this->dumpNode($node);
    }

public function dumpNode(NodeInterface $node)
    {
        $this->reference = '';
        $this->writeNode($node);
        $ref = $this->reference;
        $this->reference = null;

return $ref;
    }

private function writeNode(NodeInterface $node, NodeInterface $parentNode = null, int $depth = 0, bool $prototypedArray = false)
    {
        $comments = [];
        $default = '';
        $defaultArray = null;
        $children = null;
        $example = $node->getExample();

// defaults
        if ($node instanceof ArrayNode) {
            $children = $node->getChildren();

if ($node instanceof PrototypedArrayNode) {
                $children = $this->getPrototypeChildren($node);
            }

if (!$children) {
                if ($node->hasDefaultValue() && \count($defaultArray = $node->getDefaultValue())) {
                    $default = '';
                } elseif (!\is_array($example)) {
                    $default = '[]';
                }
            }
        } elseif ($node instanceof EnumNode) {
            $comments[] = 'One of '.implode('; ', array_map('json_encode', $node->getValues()));
            $default = $node->hasDefaultValue() ? Inline::dump($node->getDefaultValue()) : '~';
        } elseif (VariableNode::class === \get_class($node) && \is_array($example)) {
            // If there is an array example, we are sure we dont need to print a default value
            $default = '';
        } else {
            $default = '~';

if ($node->hasDefaultValue()) {
                $default = $node->getDefaultValue();

if (\is_array($default)) {
                    if (\count($defaultArray = $node->getDefaultValue())) {
                        $default = '';
                    } elseif (!\is_array($example)) {
                        $default = '[]';
                    }
                } else {
                    $default = Inline::dump($default);
                }
            }
        }

// required?
        if ($node->isRequired()) {
            $comments[] = 'Required';
        }

// deprecated?
        if ($node->isDeprecated()) {
            $comments[] = sprintf('Deprecated (%s)', $node->getDeprecationMessage($node->getName(), $parentNode ? $parentNode->getPath() : $node->getPath()));
        }

// example
        if ($example && !\is_array($example)) {
            $comments[] = 'Example: '.Inline::dump($example);
        }

$default = '' != (string) $default ? ' '.$default : '';
        $comments = \count($comments) ? '# '.implode(', ', $comments) : '';

$key = $prototypedArray ? '-' : $node->getName().':';
        $text = rtrim(sprintf('%-21s%s %s', $key, $default, $comments), ' ');

if ($info = $node->getInfo()) {
            $this->writeLine('');
            // indenting multi-line info
            $info = str_replace("\n", sprintf("\n%".($depth * 4).'s# ', ' '), $info);
            $this->writeLine('# '.$info, $depth * 4);
        }

$this->writeLine($text, $depth * 4);

// output defaults
        if ($defaultArray) {
            $this->writeLine('');

$message = \count($defaultArray) > 1 ? 'Defaults' : 'Default';

$this->writeLine('# '.$message.':', $depth * 4 + 4);

$this->writeArray($defaultArray, $depth + 1);
        }

if (\is_array($example)) {
            $this->writeLine('');

$message = \count($example) > 1 ? 'Examples' : 'Example';

$this->writeLine('# '.$message.':', $depth * 4 + 4);

$this->writeArray(array_map([Inline::class, 'dump'], $example), $depth + 1);
        }

if ($children) {
            foreach ($children as $childNode) {
                $this->writeNode($childNode, $node, $depth + 1, $node instanceof PrototypedArrayNode && !$node->getKeyAttribute());
            }
        }
    }

/**
     * Outputs a single config reference line.
     */
    private function writeLine(string $text, int $indent = 0)
    {
        $indent = \strlen($text) + $indent;
        $format = '%'.$indent.'s';

$this->reference .= sprintf($format, $text)."\n";
    }

private function writeArray(array $array, int $depth)
    {
        $isIndexed = array_values($array) === $array;

foreach ($array as $key => $value) {
            if (\is_array($value)) {
                $val = '';
            } else {
                $val = $value;
            }

if ($isIndexed) {
                $this->writeLine('- '.$val, $depth * 4);
            } else {
                $this->writeLine(sprintf('%-20s %s', $key.':', $val), $depth * 4);
            }

if (\is_array($value)) {
                $this->writeArray($value, $depth + 1);
            }
        }
    }

private function getPrototypeChildren(PrototypedArrayNode $node): array
    {
        $prototype = $node->getPrototype();
        $key = $node->getKeyAttribute();

// Do not expand prototype if it isn't an array node nor uses attribute as key
        if (!$key && !$prototype instanceof ArrayNode) {
            return $node->getChildren();
        }

if ($prototype instanceof ArrayNode) {
            $keyNode = new ArrayNode($key, $node);
            $children = $prototype->getChildren();

if ($prototype instanceof PrototypedArrayNode && $prototype->getKeyAttribute()) {
                $children = $this->getPrototypeChildren($prototype);
            }

// add children
            foreach ($children as $childNode) {
                $keyNode->addChild($childNode);
            }
        } else {
            $keyNode = new ScalarNode($key, $node);
        }

$info = 'Prototype';
        if (null !== $prototype->getInfo()) {
            $info .= ': '.$prototype->getInfo();
        }
        $keyNode->setInfo($info);

return [$key => $keyNode];
    }
}