Drush fails because "TRUE" gets passed into the Drush\Config\Environment::setLoader() call.

[erikfrerejean]

I've just installed a composer based project that includes drush, however all drush commands fail with the exception:

$ drush --help
PHP Fatal error:  Uncaught TypeError: Argument 1 passed to Drush\Config\Environment::setLoader() must be an instance of Composer\Autoload\ClassLoader, boolean given, called in /var/www/site/vendor/drush/drush/drush.php on line 57 and defined in /var/www/site/vendor/drush/drush/src/Config/Environment.php:219
Stack trace:
#0 /var/www/site/vendor/drush/drush/drush.php(57): Drush\Config\Environment->setLoader(true)
#1 /var/www/site/vendor/drush/drush/includes/preflight.inc(17): require('/var/www/site...')
#2 phar:///usr/local/bin/drush/bin/drush.php(139): drush_main()
#3 /usr/local/bin/drush(10): require('phar:///usr/loc...')
#4 {main}
  thrown in /var/www/site/vendor/drush/drush/src/Config/Environment.php on line 219

To check I've dumped both $autoloadFile and $loader to see their values and ran drush status from the site directory.

$ drush status
string(58) "/var/www/site/vendor/drush/drush/../../autoload.php"
bool(true)

The path to autoload.php is correct and the file itself is readable, $loader however is the TRUE which normally is returned by include_once.

This happens on a CentOS 7 server running PHP 7.0.20, and using Drush 9.0.0-beta7.

[weitzman]

I see phar:// in the backtrace. Is that drush8 or the drupal-launcher? what version? and what version of drupal is in the site? a `composer show` and `drush status` would give helpful info.

[erikfrerejean]

Running Drupal 8.4.

composer show output attached, drush status doesn't work since it throws the same exception before outputting anything.

I see phar:// in the backtrace. Is that drush8 or the drupal-launcher? what
version?
That is the drush launcher

[weitzman]

Sounds like your composer install is broken. I guess you should Delete vendor dir and run composer install.

[greg-1-anderson]

The autoloader returns the class loader the first time it is called, and returns true if it is called a second time. Drush 9 needs a reference to the class loader, so you shouldn't call the autoloader prior to launching Drush.

Older versions of the launcher loaded the autoloader and then included drush_main(). The newest launcher still does this for Drush 8, but skips loading the autoloader for Drush 9. You probably need to upgrade your launcher.

[erikfrerejean]

Sorry for the delay, didn't have time to update the server. @greg-1-anderson, updating the launcher indeed fixed the issue.

[fede-green]

mhm sorry @erikfrerejean . looks i'm having the same problem here... how do you update the launcher?

thanks :)