authority: address comments from PR

transport/handler_server.go

@@ -97,7 +97,7 @@ func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request) (ServerTr
 	}
 	for k, vv := range r.Header {
 		k = strings.ToLower(k)
-		if isReservedHeader(k) && !isWhitelistedHttp2Header(k){
+		if isReservedHeader(k) && !isWhitelistedPseudoHeader(k){
 			continue
 		}
 		for _, v := range vv {

transport/http2_client.go

@@ -341,6 +341,10 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	if md, ok := metadata.FromContext(ctx); ok {
 		hasMD = true
 		for k, v := range md {
+			// HTTP doesn't allow you to set pseudoheaders after non pseudoheaders were set.
+			if isReservedHeader(k) {
+				continue
+			}
 			for _, entry := range v {
 				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
 			}

transport/http_util.go

@@ -127,11 +127,11 @@ func isReservedHeader(hdr string) bool {
 	}
 }
 
-// isWhitelistedHttp2Header checks whether hdr belongs to HTTP2 headers
+// isWhitelistedPseudoHeader checks whether hdr belongs to HTTP2 pseudoheaders
 // that should be propagated into metadata visible to users.
-func isWhitelistedHttp2Header(hdr string) bool {
+func isWhitelistedPseudoHeader(hdr string) bool {
 	switch hdr {
-	case ":authority", "Authority":
+	case ":authority":
 		return true
 	default:
 		return false
@@ -173,7 +173,7 @@ func (d *decodeState) processHeaderField(f hpack.HeaderField) {
 	case ":path":
 		d.method = f.Value
 	default:
-		if !isReservedHeader(f.Name) || isWhitelistedHttp2Header(f.Name) {
+		if !isReservedHeader(f.Name) || isWhitelistedPseudoHeader(f.Name) {
 			if f.Name == "user-agent" {
 				i := strings.LastIndex(f.Value, " ")
 				if i == -1 {