drupal_composer_builder/src/MergeParamsCommand.php

<?php
declare(strict_types = 1);

namespace Fgm\Drupal\Composer;

use Drupal\Component\Utility\NestedArray;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Yaml\Yaml;

class MergeParamsCommand extends BaseBuilderCommand
{
    const DEFAULT_SITE = '_default';

    /**
   * @var string
   */
    protected $eventName;

    /**
   * {@inheritDoc}
   */
    public function configure()
    {
        parent::configure();
        $this->eventName = $this->getName();
        $this
            ->setName('build:merge_params')
            ->setDescription('Step 1: merges the params.local.yml with dist.params.local.yml.')
            ->setDefinition([])
            ->setHelp(
                <<<EOT
Step 1 of a build, the build:merge_params command combines shared and per-environment
parameters and generates merged.params.local.yml containing the merged result.

EOT
            );
    }

    protected function merge(array $dist, array $local): array
    {
        if (empty($local)) {
            return $dist;
        }

        // Merge local into defaults.
        $merged = NestedArray::mergeDeepArray([$dist, $local], true);

        // Generate per-site data from settings/_default.
        $default = $merged['sites'][static::DEFAULT_SITE] ?? [];
        $sites = array_diff_key($merged['sites'], [static::DEFAULT_SITE => null]);
        $merged['sites'] = [];
        foreach ($sites as $name => $params) {
            $merged['sites'][$name] = NestedArray::mergeDeep($default, $params);
        }
        return $merged;
    }

    /**
   * {@inheritDoc}
   */
    public function execute(InputInterface $input, OutputInterface $output)
    {
        $settingsPath = $this->getSettingsPath();
        $yaml = new Yaml();

        // Load defaults.
        $defaultsPath = "${settingsPath}/dist.params.local.yml";
        $realDefaultsPath = realpath($defaultsPath);
        if (empty($realDefaultsPath)) {
            $output->writeln("Failed to open $defaultsPath");
            return 1;
        }
        $defaults = $yaml->parseFile($realDefaultsPath);

        // Load local.
        $localPath = "${settingsPath}/params.local.yml";
        $realLocalPath = realpath($localPath);
        if (empty($realLocalPath)) {
            if ($output->isVerbose()) {
                $output->writeln("File $localPath not found, using only defaults");
            }
            $local = [];
        } else {
            $local = $yaml->parseFile($realLocalPath);
        }

        // Merge.
        $merged = $this->merge($defaults, $local);

        // Write.
        $ok = file_put_contents("${settingsPath}/merged.params.local.yml", $yaml->dump($merged, 10, 2));
        if (!$ok) {
            $output->writeln("Failed to write merged params.");
            return 2;
        }
    }
}