net/url: Trailing question marks in query string appears to be misparsed

[bjkail]

Commit 9f26170 from issue #13488 appears to improperly parse URLs if the query string ends in ?, such as http://host/?q=?. I noticed through code inspection, so I don't have a way to verify and so this issue might be invalid. The current playground seems to behave correctly: http://play.golang.org/p/khxLopsBd0

[dghubble]

I noticed this in some test logs as well. Following 9f26170, http.NewRequest fails to create a http.Request for a test URL ending in "?", due to the url.Parse change.

_, err := http.NewRequest("GET", "http://a.io?mac=?", nil)
fmt.Println(err)

Output

&url.Error{Op:"parse", URL:"http://a.io?mac=?", Err:"?"}

I expected url.Parse to parse the URL ending in "?".

[gopherbot]

CL https://golang.org/cl/20116 mentions this issue.