Releases with the same directory name causes an error

[parasquid]

For example, here: https://launchpad.net/products/openkore the confpack and OpenKore releases all lead to the same directory name https://launchpad.net/products/openkore/1.6.3 which leads to the error page.

Before I experienced this error, I was trying to update confpack with another release. However, it seems that with my slow internet connection, I managed to resend the POST data three times leading to this error.

[Diogo Matsubara (matsubara)]

A very similar problem also occurs with product series, though product series has a database constraint that ensures a unique name. Product releases have no such constraint and really blow up.

[Stuart Bishop (stub)]

ProductRelease(productseries, version) is now unique so people will not be able to create duplicate product releases.

There is still UI work to do though, as the forms still allow people to attempt to do this at which point they will get a System Error page.