src/RecipeCommandBehaviour.php
protected function findBestConstraint($existingVersion)
    {
        // Cannot guess without existing version
        if (!$existingVersion) {
            return null;
        }

        // Existing version is already a ^1.0.0 or ~1.0.0 constraint
        if (preg_match('#^[~^]#', $existingVersion)) {
            return $existingVersion;
        }

        // Existing version is already a dev constraint
        if (stristr($existingVersion, 'dev') !== false) {
            return $existingVersion;
        }

        // Numeric-only version maps to semver constraint
        if (preg_match('#^([\d.]+)$#', $existingVersion)) {
            return "^{$existingVersion}";
        }

        // Cannot guess; Let composer choose (equivalent to `composer require vendor/library`)
        return null;
    }
protected function findBestConstraint($existingVersion)
    {
        // Cannot guess without existing version
        if (!$existingVersion) {
            return null;
        }

        // Existing version is already a ^1.0.0 or ~1.0.0 constraint
        if (preg_match('#^[~^]#', $existingVersion)) {
            return $existingVersion;
        }

        // Existing version is already a dev constraint
        if (stristr($existingVersion, 'dev') !== false) {
            return $existingVersion;
        }

        // Numeric-only version maps to semver constraint
        if (preg_match('#^([\d.]+)$#', $existingVersion)) {
            return "^{$existingVersion}";
        }

        // Cannot guess; Let composer choose (equivalent to `composer require vendor/library`)
        return null;
    }
protected function findBestConstraint ( $ existingVersion ) { // Cannot guess without existing version if ( ! $ existingVersion ) { return null ; } // Existing version is already a ^1.0.0 or ~1.0.0 constraint if ( preg_match ( '#^[~^]#' , $ existingVersion ) ) { return $ existingVersion ; } // Existing version is already a dev constraint if ( stristr ( $ existingVersion , 'dev' ) !== false ) { return $ existingVersion ; } // Numeric-only version maps to semver constraint if ( preg_match ( '#^([\d.]+)$#' , $ existingVersion ) ) { return "^{$existingVersion}" ; } // Cannot guess; Let composer choose (equivalent to `composer require vendor/library`) return null ; }
Guess constraint to use if not provided

@param string $existingVersion Known installed version
@return string
Guess constraint to use if not provided