Fatal error: Cannot use Composer\Installer as Installer because the name is already in use in phar:///usr/local/bin/composer/src/Composer/Plugin/PluginManager.php(195) : eval()'d code on line 13

[magicento]

` - Installing composer/semver (1.4.2) Loading from cache

• Installing composer/composer (1.0.0-beta1) Loading from cache
• Installing magento/composer (1.0.3) Loading from cache
• Installing tedivm/jshrink (v1.0.1) Loading from cache
• Installing phpseclib/phpseclib (2.0.4) Loading from cache
• Installing symfony/event-dispatcher (v2.8.17) Loading from cache
• Installing tubalmartin/cssmin (v2.4.8-p4) Loading from cache
• Installing pelago/emogrifier (v0.1.1) Loading from cache
• Installing oyejorge/less.php (v1.7.0.10) Loading from cache
• Installing monolog/monolog (1.16.0) Loading from cache
• Installing magento-hackathon/magento-composer-installer (3.0.7) Loading from cache

Fatal error: Cannot use Composer\Installer as Installer because the name is already in use in phar:///usr/local/bin/composer/src/Composer/Plugin/PluginManager.php(195) : eval()'d code on line 13
`

[Flyingmana]

how can I reproduce this?

[cyxddgithub]

hi @Flyingmana i also meet this problem.

composer create-project --repository-url=https://repo.magento.com/ magento/project-community-edition ./e_commerce_magento/
Installing magento/project-community-edition (2.1.5)

• Installing magento/project-community-edition (2.1.5)
  Loading from cache

Created project in ./e_commerce_magento/
Loading composer repositories with package information
...

PHP Fatal error: Cannot use Composer\Installer as Installer because the name is already in use in phar:///usr/local/bin/composer/src/Composer/Plugin/PluginManager.php(193) : eval()'d code on line 13

[Flyingmana]

@cyxddgithub your error occures for Magento2, where the "magento-hackathon/magento-composer-installer" should not be used for (its only for magento1)
seems like this M2 related bug should be reported to magento instead

[davidverholen]

just an idea: do you maybe have the hackathon composer installer installed globally?
you should be able to see that with composer global show -i (the -i param is only needed in older composer versions)

[cyxddgithub]

@davidverholen here is my composer show result seem lick no global install it:
Changed current directory to /home/vagrant/.composer
doctrine/inflector v1.1.0 Common String Manipulations with regard to casing and singular/plural rules.
guzzlehttp/guzzle 6.2.0 Guzzle is a PHP HTTP client library
guzzlehttp/promises 1.2.0 Guzzle promises library
guzzlehttp/psr7 1.3.1 PSR-7 message implementation
illuminate/contracts v5.2.37 The Illuminate Contracts package.
illuminate/support v5.2.37 The Illuminate Support package.
laravel/envoy v1.2.0 Elegant SSH tasks for PHP.
laravel/installer v1.3.3 Laravel application installer.
nategood/httpful 0.2.20 A Readable, Chainable, REST friendly, PHP HTTP Client
paragonie/random_compat v1.4.1 PHP 5.x polyfill for random_bytes() and random_int() from PHP 7
psr/http-message 1.0 Common interface for HTTP messages
symfony/console v3.1.1 Symfony Console Component
symfony/polyfill-mbstring v1.2.0 Symfony polyfill for the Mbstring extension
symfony/process v3.1.1 Symfony Process Component

@Flyingmana got it i have try report it in magento2 issue

[davidverholen]

I think it's still another problem, since magento 2 would not require the hackathon composer installer.
Try executing

composer why magento-hackathon/magento-composer-installer

it should show you the module, that requires the hackathon installer. Most likely you have a Magento1 Module in your requirements