Joomla-CMS: JInstallerHelper::downloadPackage patch to encode url query values

helper.php

/**
 * JInstallerHelper::downloadPackage patch to encode redirect url query values.
 *
 * File Locations: 
 * - J3.2: /libraries/cms/installer/helper.php
 * - J2.5: /libraries/joomla/installer/helper.php
 *
 * For performance reasons (assuming that initial $url is valid),
 * this code can be moved just under the `302 == $response->code` check.
 */
public static function downloadPackage($url, $target = false)
{
	/* JInstallerHelper::downloadPackage patch to encode url query values
	 */

	// Using JUri here (not parse_url) to preserve non-query data
	$uri = new JUri($url);

	// Get query variables
	$vars  = $uri->getQuery(true);

	// Encode values
	array_walk_recursive($vars, 'rawurlencode');

	// Set query and convert to string
	$uri->setQuery($vars);
	$url = (string) $uri;

	// Rest of the code
	//...
}

which version is this? J3.x? My downloadPackage (libraries/joomla/installer/helper.php, right?) in 2.5.17 looks nothing like this. Or is it just to be inserted at the beginning of the method?

Yeah, at the very beginning of downloadPackage method. Be warned, that I didn't test it at all.
To debug, see if this
if (strpos($url, 'https://s3.amazonaws.com/github-cloud/') === 0) { print_r($url); die('-') }} is properly escaped.

The difference is that in 3.2 helper.php is located in libraries/cms/installer and 2.5 in libraries/joomla/installer.