net/url: Parse not working correctly for a non absolute URL with port.

[zbindenren]

What version of Go are you using (go version)?

go version go1.9.1 linux/amd64

Does this issue reproduce with the latest release?

Yes: https://play.golang.org/p/yoLxXnHE1J

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/rz/golang"
GORACE=""
GOROOT="/home/rz/.gimme/versions/go1.9.1.linux.amd64"
GOTOOLDIR="/home/rz/.gimme/versions/go1.9.1.linux.amd64/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build155424131=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"

What did you do?

url.Parse not working for relative url with port.

When parsing www.example.com:443, IsAbs returns true, and port is empty.

https://play.golang.org/p/yoLxXnHE1J

What did you expect to see?

IsAbs returns false.

What did you see instead?

IsAbs returns true.

[bradfitz]

Dup of #21415

That is not a valid URL. An absolute URL starts with a scheme (http://, etc) and a relative URL must never contain a colon in its first path element, per the specs.

[zbindenren]

@bradfitz Shouldn't Parse return an error in that case?

[bradfitz]

Just keep in mind that you're parsing either a full URL or just a path. Other crap tends to end up in Path or Opaque (https://play.golang.org/p/vbQkLpYwRX) if it's malformed and not one of those forms, but don't depend on how malformed stuff gets parsed.

[gopherbot]

Change https://golang.org/cl/81436 mentions this issue: net/url: document Parse more