net/http: remove invalid checks of Request.Proto* for outgoing requests

The net/http package has long documented that Request.ProtoMajor and
Request.ProtoMinor are ignored for outgoing requests (HTTP/1.1 or
HTTP/2 is always used, never HTTP/1.0). There was one part in the code
that was actually checking 1.0 vs 1.1, but it appears to have been
harmless. Remove it.

Fixes #18407

Change-Id: I362ed6c47ca2de7a2fbca917ed3e866273cfe41f
Reviewed-on: https://go-review.googlesource.com/45155
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/http/request.go

@@ -349,18 +349,6 @@ func (r *Request) ProtoAtLeast(major, minor int) bool {
 		r.ProtoMajor == major && r.ProtoMinor >= minor
 }
 
-// protoAtLeastOutgoing is like ProtoAtLeast, but is for outgoing
-// requests (see issue 18407) where these fields aren't supposed to
-// matter.  As a minor fix for Go 1.8, at least treat (0, 0) as
-// matching HTTP/1.1 or HTTP/1.0.  Only HTTP/1.1 is used.
-// TODO(bradfitz): ideally remove this whole method. It shouldn't be used.
-func (r *Request) protoAtLeastOutgoing(major, minor int) bool {
-	if r.ProtoMajor == 0 && r.ProtoMinor == 0 && major == 1 && minor <= 1 {
-		return true
-	}
-	return r.ProtoAtLeast(major, minor)
-}
-
 // UserAgent returns the client's User-Agent, if sent in the request.
 func (r *Request) UserAgent() string {
 	return r.Header.Get("User-Agent")

src/net/http/transfer.go

@@ -99,13 +99,13 @@ func newTransferWriter(r interface{}) (t *transferWriter, err error) {
 		t.TransferEncoding = rr.TransferEncoding
 		t.Header = rr.Header
 		t.Trailer = rr.Trailer
-		atLeastHTTP11 = rr.protoAtLeastOutgoing(1, 1)
 		t.Body = rr.Body
 		t.BodyCloser = rr.Body
 		t.ContentLength = rr.outgoingLength()
-		if t.ContentLength < 0 && len(t.TransferEncoding) == 0 && atLeastHTTP11 && t.shouldSendChunkedRequestBody() {
+		if t.ContentLength < 0 && len(t.TransferEncoding) == 0 && t.shouldSendChunkedRequestBody() {
 			t.TransferEncoding = []string{"chunked"}
 		}
+		atLeastHTTP11 = true // Transport requests are always 1.1 or 2.0
 	case *Response:
 		t.IsResponse = true
 		if rr.Request != nil {