RedirectView(query_string=True) produces double '?' when both destination URL and request have query parameters

[Ethan Jucovy]

When using the generic RedirectView(query_string=True) with a query string in the destination URL, the view always appends query string parameters from the incoming request with a ? separator. It should use & if there's also an existing query string in the incoming URL.

Currently, requests that come in with a query string end up redirected to a URL containing two question marks, e.g.:

path("redirect-me/", RedirectView.as_view(url="/destination/?pork=spam", query_string=True))

GET /redirect-me/?utm_source=foo

Currently results in:

Location: /destination/?pork=spam?utm_source=foo

Expected:

Location: /destination/?pork=spam&utm_source=foo

[Ethan Jucovy]

PR: ​https://github.com/django/django/pull/19610

[Natalia Bidart]

Hello Ethan Jucovy, thank you for taking the time to create this ticket and the PR. I think your report makes sense, I would also expect ? and & to be properly handled. Having said that, the current url manipulation logic feels somehow brittle and I wonder if we should consider a more robust implementation using urlparse. Have your given this some thought?

[umesh singh bisht]

Hi @EthanJucovy!
I'd love to take on this ticket as my first contribution to Django.
I've analyzed the problem in the get_redirect_url method and have a clean, backward-compatible solution ready. The fix should be just changing the hardcoded '?' separator to use '&' when the destination URL already contains query parameters. Whats your thought about this.