Allow test Client to re-use query string for non-GET requests when following 307/308 redirects.

[Max Crowe]

If an application uses an HTTP 307 or 308 response to redirect /foo/ to /bar/?a=b, when the test client is instructed to follow redirects, the ultimate request will be to /bar/ (with no query string). This is due to the fact that the test client only examines the query portion of the response URL if the HTTP status is not 307 or 308:

if response.status_code in (HTTPStatus.TEMPORARY_REDIRECT, HTTPStatus.PERMANENT_REDIRECT):
    # Preserve request method post-redirect for 307/308 responses.
    request_method = getattr(self, response.request['REQUEST_METHOD'].lower())
else:
    request_method = self.get
    data = QueryDict(url.query)
    content_type = None

The test client should respect query strings indicated in redirect URLs, even if the request method is something other than GET or HEAD.

[Carlton Gibson]

OK, so there's a valid use-case here I think. One should be able to explicitly pass the query string when creating the redirect response. Such as:

HttpResponseRedirect("/post_view/?hello=world", status=307)

Expecting both the original POST data and the query string to be resubmitted when following the redirect. (Assuming a POST request in the first place.)

Examining the test client behaviour, the redirect_chain is correct (e.g. response.redirect_chain[0] gives ('/post_view/?hello=world', 307)) but the final request query string is empty, as per the report.

_handle_redirects() receives the correct request, including the query string, but this gets dropped by the urlsplit call, and as Max says is not then reused.

Where method != 'GET' path should have the query parameters re-appended in this case.

I'll mark this a new feature since it's never been supported. (Arguably could have been part of 272f685794de0b8dead220ee57b30e65c9aa097c but...)

[Max Crowe]

The test client in Django 2.0 would actually reuse the query string as expected in this scenario; however, this was sort of a consequence of it failing to preserve the request method for 307 and 308 redirects.

[Ahmad Abdallah]

As stated on the PR, this patch is incorrect. Fixing it now.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 6425fd3:

Refs #31494 -- Added test for query strings for GET/HEAD requests when following HTTP 307/308 redirects in test client.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 7c947f0:

Fixed #31494 -- Preserved query strings when following HTTP 307/308 redirects in test client.