Symfony 3.4, composer post-install-cmd, and env() parameters a default value

Question

I try to follow the Symfony 3.4 documentation in order to use the environment variables and their default value https://symfony.com/doc/3.4/configuration/external_parameters.html

As the documentation suggest, i try to put the env parameter and his default value:

parameters:
    env(DATABASE_HOST): 127.0.0.1
    database_host: '%env(DATABASE_HOST)%'

But when i try to execute composer, composer dump-autoload --optimize && composer run-script post-install-cmd

I have this exception

> Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::clearCache

In EnvVarProcessor.php line 76:

  Environment variable not found: "DATABASE_HOST".


Script Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::clearCache handling the post-install-cmd event terminated with an exception


  [RuntimeException]
  An error occurred when executing the "'cache:clear --no-warmup'" command:




  In EnvVarProcessor.php line 76:

    Environment variable not found: "DATABASE_HOST".


run-script [--timeout TIMEOUT] [--dev] [--no-dev] [-l|--list] [--] [<script>] [<args>]...

Look like that composer ignore the default parameter value.

Answer 1

I got almost the same scenario; I tried to maker migration from Symfony 3.3 => 3.4 and I got excited to use Environment Variable Processors but need to be configure:

After reading how to use https://symfony.com/doc/current/components/dotenv.html is not enough here is the steps how to configure Dotenv

run command bellow to update composer.json composer require --dev symfony/dotenv

web/app_dev.yml

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Debug\Debug;
use Symfony\Component\Dotenv\Dotenv;
...

/**
 * @var Composer\Autoload\ClassLoader $loader
 */
$loader = require __DIR__.'/../vendor/autoload.php';
Debug::enable();

$dotenv = new Dotenv();
$dotenv->load(__DIR__.'/../.env');

$kernel = new AppKernel('dev', true);

...

bin/console.php

use Symfony\Bundle\FrameworkBundle\Console\Application;
use Symfony\Component\Console\Input\ArgvInput;
use Symfony\Component\Debug\Debug;
use Symfony\Component\Dotenv\Dotenv;

...

$loader = require __DIR__.'/../vendor/autoload.php';

$input = new ArgvInput();
$env = $input->getParameterOption(array('--env', '-e'), getenv('SYMFONY_ENV') ?: 'dev');
$debug = getenv('SYMFONY_DEBUG') !== '0' && !$input->hasParameterOption(array('--no-debug', '')) && $env !== 'prod';

if ($env === 'dev') {
    $dotenv = new Dotenv();
    $dotenv->load(__DIR__.'/../.env');
}

if ($debug) {
    Debug::enable();
}
...