src/Composer/Package/Archiver/ArchiveManager.php
public function getPackageFilename(PackageInterface $package)
    {
        $nameParts = array(preg_replace('#[^a-z0-9-_]#i', '-', $package->getName()));

        if (preg_match('{^[a-f0-9]{40}$}', $package->getDistReference())) {
            array_push($nameParts, $package->getDistReference(), $package->getDistType());
        } else {
            array_push($nameParts, $package->getPrettyVersion(), $package->getDistReference());
        }

        if ($package->getSourceReference()) {
            $nameParts[] = substr(sha1($package->getSourceReference()), 0, 6);
        }

        $name = implode('-', array_filter($nameParts, function ($p) {
            return !empty($p);
        }));

        return str_replace('/', '-', $name);
    }
public function getPackageFilename(PackageInterface $package)
    {
        $nameParts = array(preg_replace('#[^a-z0-9-_]#i', '-', $package->getName()));

        if (preg_match('{^[a-f0-9]{40}$}', $package->getDistReference())) {
            array_push($nameParts, $package->getDistReference(), $package->getDistType());
        } else {
            array_push($nameParts, $package->getPrettyVersion(), $package->getDistReference());
        }

        if ($package->getSourceReference()) {
            $nameParts[] = substr(sha1($package->getSourceReference()), 0, 6);
        }

        $name = implode('-', array_filter($nameParts, function ($p) {
            return !empty($p);
        }));

        return str_replace('/', '-', $name);
    }
Generate a distinct filename for a particular version of a package.

@param PackageInterface $package The package to get a name for

@return string A filename without an extension