src/Composer/Config/JsonConfigSource.php
public function addRepository($name, $config)
    {
        $this->manipulateJson('addRepository', $name, $config, function (&$config, $repo, $repoConfig) {
            // if converting from an array format to hashmap format, and there is a {"packagist.org":false} repo, we have
            // to convert it to "packagist.org": false key on the hashmap otherwise it fails schema validation
            if (isset($config['repositories'])) {
                foreach ($config['repositories'] as $index => $val) {
                    if ($index === $repo) {
                        continue;
                    }
                    if (is_numeric($index) && ($val === array('packagist' => false) || $val === array('packagist.org' => false))) {
                        unset($config['repositories'][$index]);
                        $config['repositories']['packagist.org'] = false;
                        break;
                    }
                }
            }

            $config['repositories'][$repo] = $repoConfig;
        });
    }
public function addRepository($name, $config)
    {
        $this->manipulateJson('addRepository', $name, $config, function (&$config, $repo, $repoConfig) {
            // if converting from an array format to hashmap format, and there is a {"packagist.org":false} repo, we have
            // to convert it to "packagist.org": false key on the hashmap otherwise it fails schema validation
            if (isset($config['repositories'])) {
                foreach ($config['repositories'] as $index => $val) {
                    if ($index === $repo) {
                        continue;
                    }
                    if (is_numeric($index) && ($val === array('packagist' => false) || $val === array('packagist.org' => false))) {
                        unset($config['repositories'][$index]);
                        $config['repositories']['packagist.org'] = false;
                        break;
                    }
                }
            }

            $config['repositories'][$repo] = $repoConfig;
        });
    }
{@inheritdoc}