Redirect back to Event Registration after login fails

Question

I've implemented user accounts during Event registration by enabling the profile's advanced settings to give the user the option to create a Joomla account.

When a user registers for an event, they are correctly offered the chance to sign-up or login:

If you would like to create an account on this site, check the box below and enter a Username and a password. If you already have an account please login before completing this form.

The 'login' word above is hotlinked to a page which allows the user to login and then CiviCRM should return the user back to the Event Registration page. It does not - after logging in, the user just gets a blank page.

The reason seems to be that the redirect page is malformed; it is:

/index.php?option=com_civicrm&task=civicrm/event/register&reset=1&id=60

when it should be:

/index.php?option=com_civicrm&task=civicrm/event/register&reset=1&id=60

The & concatenators in the URL are being incorrectly escaped. Any ideas how to address this?

Answer 1

Fix proposed here to turn off the cleansing of the redirect URL: https://github.com/civicrm/civicrm-core/pull/6183

Answer 2

As suggested on the question related to Contributions above, I have duplicated this error on the demo site.

I created a profile that gives the option to login and, after logging in, the redirection failed due to this invalid URL: http://joomla.demo.civicrm.org/index.php?option=com_civicrm&task=civicrm/event/register&reset=1&id=8

I think the problem is in the coding of this link (which is used to redirect the user to login): http://joomla.demo.civicrm.org/index.php?option=com_users&view=login&return=aHR0cDovL2pvb21sYS5kZW1vLmNpdmljcm0ub3JnL2luZGV4LnBocD9vcHRpb249Y29tX2Npdmljcm0mYW1wO3Rhc2s9Y2l2aWNybS9ldmVudC9yZWdpc3RlciZhbXA7cmVzZXQ9MSZhbXA7aWQ9OA%3D%3D

I am going to raise a bug and will post the link here after.