proposal: net/url: provide AllowQuerySemicolons functionality for net/url rather than net/http

[chrisguiney]

#25192 was a breaking change and #45973 sought to alleviate that change with AllowQuerySemicolons. Implementing it as an http handler however ignores any other use case for parsing urls.

My understanding is that anything parsing doubleclick urls, which explicitly use semicolons, would still break.

https://support.google.com/richmedia/answer/117426?hl=en

It would be great if we could have some mechanism to allow for backward compatibility in net/url rather than net/http, so that all use cases can be accommodated.

[ianlancetaylor]

CC @FiloSottile

[FiloSottile]

Not saying that we necessarily shouldn’t do this, but it’s worth noting that if you have a URL, getting the original behavior back is a single call to strings.Replace(u, “;”, “&”, -1).

[chrisguiney]

One suggestion might be viable would be to simply return an error, such as url.ErrLegacyQuerySep or something to denote that it was parsed correctly, but contained semicolons. This would likely make all existing clients ignore the returned value, and bubble up the error.

Another option would be to make a function that takes a set of valid separators to use.

[gopherbot]

Change https://golang.org/cl/338750 mentions this issue: doc/go1.17: suggest method of restoring prior behavior of url.Parse

[neild]

Using strings.Replace seems simpler than adding additional API surface to url.Parse. Sent a CL to add this suggestion to the release notes, since it isn't immediately obvious that it's a valid workaround.

[rsc]

Given updated docs, it doesn't seem like we need to put this API in.

[rsc]

This proposal has been added to the active column of the proposals project
and will now be reviewed at the weekly proposal review meetings.
— rsc for the proposal review group

[rsc]

Based on the discussion above, this proposal seems like a likely decline.
— rsc for the proposal review group

[rsc]

No change in consensus, so declined.
— rsc for the proposal review group