Add a new version of Magento to a repository compatible with https://github.com/AydinHassan/magento-core-composer-installer

add-magento-version.php

<?php

/**
 * Script to manage to version of Magento in a git mirror
 * php $argv[0] core-repository new-version-of-magento
 * 
 * It will look for Mage.php in new-version-of-magento and parse the version
 * and edition from it.
 * 
 * It will copy the code, remove the old files, create new branches if necessary
 * and tag the release.
 * 
 * Branches are major.minor
 * 
 * so 1.9.0.0, 1.9.0.1, 1.9.10 all go in the 1.9 branch
 * 1.10.0.0 would cause a new 1.10 branch to be created.
 * 
 * 1.10 will be branched of 1.9 so you can diff them easily
 * 
 * @author Aydin Hassan <aydin@hotmail.co.uk>
 */

function cp($from, $to) {
    $iterator = new \RecursiveIteratorIterator(
        new \RecursiveDirectoryIterator($from, \RecursiveDirectoryIterator::SKIP_DOTS),
        \RecursiveIteratorIterator::SELF_FIRST
    );
    foreach ($iterator as $item) {
        if ($item->isDir()) {
            mkdir($to . "/" . $iterator->getSubPathName());
        } else {
            copy($item, $to . "/" . $iterator->getSubPathName());
        }
    }
}

function rmOldMagento()
{
    exec("rm -rf *");
    exec("rm -rf *.ht");
}

function commitAndTag($version, $edition)
{
    exec("git add --all");
    exec("git commit -m 'Magento $edition $version'");
    exec("git tag $version");
}

function parseCore($location) {
    if (!file_exists(rtrim($location, "/") . "/app/Mage.php")) {
        die("$location does not look like a Magento code base");
    }

    require_once rtrim($location, "/") . "/app/Mage.php";
    $edition = Mage::getEdition();
    $version = Mage::getVersionInfo();
    $versionStr = Mage::getVersion();
    return array('edition' => $edition, 'version' => $version, 'versionStr' => $versionStr);
}

if (!isset($argv[1]) || !isset($argv[2])) {
    die("{$argv[0]} core-repo magento-code-location");
}

$coreRepoLocation = $argv[1];
$coreLocation = $argv[2];
$packageName = isset($argv[3]) ? $argv[3] : 'magento/magento';

if (!file_exists($coreRepoLocation)) {
    die("Core Repo Location is invalid");
}
$info = parseCore($coreLocation);

$coreRepoLocation = realpath($coreRepoLocation);
chdir($coreRepoLocation);
exec("git for-each-ref refs/heads/ --format='%(refname:short)'", $branches);

usort($branches, function ($a, $b) {
    return version_compare($a, $b);
});

$composerFile = '{
    "name": "' . $packageName . '",
    "description": "Magento ' . $info['edition'] . '",
    "type": "magento-core"
}';

$major = $info['version']['major'];
$minor = $info['version']['minor'];
$version = $info['versionStr'];

$branch = $major . "." . $minor;

if (!count($branches)) {
    exec("git checkout -b $branch");
    cp($coreLocation, $coreRepoLocation);
    file_put_contents("composer.json", $composerFile);
    commitAndTag($version, $info['edition']);
    exit("Created branch: $branch and tagged: $version");
}

$earliestBranch = $branches[0];
if (version_compare($version, $earliestBranch, '<')) {
    die("Adding previous releases not supported");
}

$foundBranch = false;
foreach ($branches as $b) {
    if ($b === $branch) {
        $foundBranch = true;
    }
}

if ($foundBranch) {
    exec("git checkout $branch");
    rmOldMagento();
    cp($coreLocation, $coreRepoLocation);
    file_put_contents("composer.json", $composerFile);
    commitAndTag($version, $info['edition']);
    exit("Added to branch: $branch and tagged: $version");
}

$mostRecentVersion = end($branches);

if (version_compare($version, $mostRecentVersion, '<')) {
   die("Adding new previous minors is unsupported");
}

exec("git checkout -b $branch $mostRecentVersion");
rmOldMagento();
cp($coreLocation, $coreRepoLocation);
file_put_contents("composer.json", $composerFile);
commitAndTag($version, $info['edition']);
exit("Created new branch: $branch and tagged: $version");

Great Scripts. Thanks.
I had errors with this until I changed paths in command line to absolute. MAybes you should mention it.

For Magento Enterprise 1.9.1.1

php add-magento-version.php ~/Projects/ REDACTED /magento-enterprise ~/Projects/ REDACTED /1.9.1.1

...and the following error is the result.

PHP Fatal error:  Uncaught Error: Call to undefined method Mage::getEdition() in /Users/Dan/add-magento-version.php:56
Stack trace:
#0 /Users/Dan/add-magento-version.php(73): parseCore('/Users/Dan/Proj...')
#1 {main}
  thrown in /Users/Dan/add-magento-version.php on line 56

Fatal error: Uncaught Error: Call to undefined method Mage::getEdition() in /Users/Dan/add-magento-version.php:56
Stack trace:
#0 /Users/Dan/add-magento-version.php(73): parseCore('/Users/Dan/Proj...')
#1 {main}
  thrown in /Users/Dan/add-magento-version.php on line 56

Just got back to this. A quick search returns that the getEdition method wasn't available until Magento Community 1.7 or EE 1.12.

This confused me

This confused me

This confused me

This confused me

@SageRiley2015 obviously!