net/url: Request with %2F is not transmitted correctly

[burmanm]

go version 1.4.2, Linux x64

When trying to form an URL with escaped "/" (%2F) the handling in net/url either removes the escaping or does double escaping (in which case the requested URL is wrong).

http://play.golang.org/p/1vDHT_p-cZ

The same issue of course makes calling the http.NewRequest also impossible as the given URL is not honored (escaped characters are removed, since the method calls url.Parse) and the wrong URL is called on the other end.

Expected result: QueryEscaped URL should not be modified. Has resemblance to issue #2782

[minux]

Please see http://golang.org/pkg/net/url/#URL Note that the Path field is stored in decoded form: /%47%6f%2f becomes /Go/. A consequence is that it is impossible to tell which slashes in the Path were slashes in the raw URL and which were %2f. This distinction is rarely important, but when it is a client must use other routines to parse the raw URL or construct the parsed URL. For example, an HTTP server can consult req.RequestURI, and an HTTP client can use URL{Host: "example.com", Opaque: "//example.com/Go%2f"} instead of URL{Host: "example.com", Path: "/Go/"}.