x/pkgsite: Redirects of certain packages lose version information

[tushar-deepsource]

What is the URL of the page with the issue?

https://pkg.go.dev/http@go1.16.13

What did you expect to see?

It should have redirected to https://pkg.go.dev/net/http@go1.16.13

What did you see instead?

It redirected to https://pkg.go.dev/net/http

[hyangah]

@jamalc @julieqiu @jba Do you remember why pkgsite is supporting this http redirect? And what's the rule?
(I tried https://pkg.go.dev/pprof and this is an error)

From old go documentation code https://github.com/golang/website/blob/6b9583b28385477c088e8c70a2f6012251bdd0e7/internal/redirect/redirect.go#L61 I see this redirect was added to help people transitioning from pre-go1 to go1. But It was a decade ago.

[jamalc]

That logic was added here and only works if there is a single match. The path "/pprof" matches both "net/http/pprof" and "runtime/pprof" so a 404 is returned instead.