src/Composer/DependencyResolver/RuleSetGenerator.php
protected function createConflictRule(PackageInterface $issuer, PackageInterface $provider, $reason, $reasonData = null)
    {
        // ignore self conflict
        if ($issuer === $provider) {
            return null;
        }

        return new Rule(array(-$issuer->id, -$provider->id), $reason, $reasonData);
    }
protected function createConflictRule(PackageInterface $issuer, PackageInterface $provider, $reason, $reasonData = null)
    {
        // ignore self conflict
        if ($issuer === $provider) {
            return null;
        }

        return new Rule(array(-$issuer->id, -$provider->id), $reason, $reasonData);
    }
protected function createConflictRule ( PackageInterface $ issuer , PackageInterface $ provider , $ reason , $ reasonData = null ) { // ignore self conflict if ( $ issuer === $ provider ) { return null ; } return new Rule ( array ( - $ issuer -> id , - $ provider -> id ) , $ reason , $ reasonData ) ; }
Creates a rule for two conflicting packages

The rule for conflicting packages A and B is (-A|-B). A is called the issuer
and B the provider.

@param  PackageInterface $issuer     The package declaring the conflict
@param  PackageInterface $provider   The package causing the conflict
@param  int              $reason     A RULE_* constant describing the
reason for generating this rule
@param  mixed            $reasonData Any data, e.g. the package name, that
goes with the reason
@return Rule             The generated rule
Creates a rule for two conflicting packages