update with changes from go1.20.5 to go1.21.4

http/server.go

@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
+// TINYGO: The following is copied and modified from Go 1.21.4 official implementation.
 
 // TINYGO: atomic.Pointer and atomic.Uint64 are added in Go 1.19, so keep
 // pre-1.19 code to cover min TinyGo.  If TinyGo min moves to 1.19 or higher,
@@ -469,6 +469,10 @@ type response struct {
 	// Content-Length.
 	closeAfterReply bool
 
+	// When fullDuplex is false (the default), we consume any remaining
+	// request body before starting to write a response.
+	fullDuplex bool
+
 	// requestBodyLimitHit is set by requestTooLarge when
 	// maxBytesReader hits its max size. It is checked in
 	// WriteHeader, to make sure we don't consume the
@@ -506,6 +510,11 @@ func (c *response) SetWriteDeadline(deadline time.Time) error {
 	return c.conn.rwc.SetWriteDeadline(deadline)
 }
 
+func (c *response) EnableFullDuplex() error {
+	c.fullDuplex = true
+	return nil
+}
+
 // TrailerPrefix is a magic prefix for ResponseWriter.Header map keys
 // that, if present, signals that the map entry is actually for
 // the response trailers, and not the response headers. The prefix
@@ -1162,8 +1171,11 @@ func (w *response) WriteHeader(code int) {
 	}
 	checkWriteHeaderCode(code)
 
-	// Handle informational headers
-	if code >= 100 && code <= 199 {
+	// Handle informational headers.
+	//
+	// We shouldn't send any further headers after 101 Switching Protocols,
+	// so it takes the non-informational path.
+	if code >= 100 && code <= 199 && code != StatusSwitchingProtocols {
 		// Prevent a potential race with an automatically-sent 100 Continue triggered by Request.Body.Read()
 		if code == 100 && w.canWriteContinue.isSet() {
 			w.writeContinueMu.Lock()
@@ -1325,7 +1337,7 @@ func (cw *chunkWriter) writeHeader(p []byte) {
 	// send a Content-Length header.
 	// Further, we don't send an automatic Content-Length if they
 	// set a Transfer-Encoding, because they're generally incompatible.
-	if w.handlerDone.isSet() && !trailers && !hasTE && bodyAllowedForStatus(w.status) && header.get("Content-Length") == "" && (!isHEAD || len(p) > 0) {
+	if w.handlerDone.isSet() && !trailers && !hasTE && bodyAllowedForStatus(w.status) && !header.has("Content-Length") && (!isHEAD || len(p) > 0) {
 		w.contentLength = int64(len(p))
 		setHeader.contentLength = strconv.AppendInt(cw.res.clenBuf[:0], int64(len(p)), 10)
 	}
@@ -1371,14 +1383,14 @@ func (cw *chunkWriter) writeHeader(p []byte) {
 		w.closeAfterReply = true
 	}
 
-	// Per RFC 2616, we should consume the request body before
-	// replying, if the handler hasn't already done so. But we
-	// don't want to do an unbounded amount of reading here for
-	// DoS reasons, so we only try up to a threshold.
-	// TODO(bradfitz): where does RFC 2616 say that? See Issue 15527
-	// about HTTP/1.x Handlers concurrently reading and writing, like
-	// HTTP/2 handlers can do. Maybe this code should be relaxed?
-	if w.req.ContentLength != 0 && !w.closeAfterReply {
+	// We do this by default because there are a number of clients that
+	// send a full request before starting to read the response, and they
+	// can deadlock if we start writing the response with unconsumed body
+	// remaining. See Issue 15527 for some history.
+	//
+	// If full duplex mode has been enabled with ResponseController.EnableFullDuplex,
+	// then leave the request body alone.
+	if w.req.ContentLength != 0 && !w.closeAfterReply && !w.fullDuplex {
 		var discard, tooBig bool
 
 		switch bdy := w.req.Body.(type) {
@@ -1766,7 +1778,7 @@ type closeWriter interface {
 
 var _ closeWriter = (*net.TCPConn)(nil)
 
-// closeWrite flushes any outstanding data and sends a FIN packet (if
+// closeWriteAndWait flushes any outstanding data and sends a FIN packet (if
 // client is connected via TCP), signaling that we're done. We then
 // pause for a bit, hoping the client processes it before any
 // subsequent RST.
@@ -1861,7 +1873,9 @@ func isCommonNetReadError(err error) bool {
 
 // Serve a new connection.
 func (c *conn) serve(ctx context.Context) {
-	c.remoteAddr = c.rwc.RemoteAddr().String()
+	if ra := c.rwc.RemoteAddr(); ra != nil {
+		c.remoteAddr = ra.String()
+	}
 	ctx = context.WithValue(ctx, LocalAddrContextKey, c.rwc.LocalAddr())
 	var inFlightResponse *response
 	defer func() {
@@ -2258,7 +2272,7 @@ func RedirectHandler(url string, code int) Handler {
 // Longer patterns take precedence over shorter ones, so that
 // if there are handlers registered for both "/images/"
 // and "/images/thumbnails/", the latter handler will be
-// called for paths beginning "/images/thumbnails/" and the
+// called for paths beginning with "/images/thumbnails/" and the
 // former will receive requests for any other paths in the
 // "/images/" subtree.
 //
@@ -2873,23 +2887,9 @@ func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {
 		handler = globalOptionsHandler{}
 	}
 
-	if req.URL != nil && strings.Contains(req.URL.RawQuery, ";") {
-		var allowQuerySemicolonsInUse int32
-		req = req.WithContext(context.WithValue(req.Context(), silenceSemWarnContextKey, func() {
-			atomic.StoreInt32(&allowQuerySemicolonsInUse, 1)
-		}))
-		defer func() {
-			if atomic.LoadInt32(&allowQuerySemicolonsInUse) == 0 {
-				sh.srv.logf("http: URL query contains semicolon, which is no longer a supported separator; parts of the query may be stripped when parsed; see golang.org/issue/25192")
-			}
-		}()
-	}
-
 	handler.ServeHTTP(rw, req)
 }
 
-var silenceSemWarnContextKey = &contextKey{"silence-semicolons"}
-
 // AllowQuerySemicolons returns a handler that serves requests by converting any
 // unescaped semicolons in the URL query to ampersands, and invoking the handler h.
 //
@@ -2901,9 +2901,6 @@ var silenceSemWarnContextKey = &contextKey{"silence-semicolons"}
 // AllowQuerySemicolons should be invoked before Request.ParseForm is called.
 func AllowQuerySemicolons(h Handler) Handler {
 	return HandlerFunc(func(w ResponseWriter, r *Request) {
-		if silenceSemicolonsWarning, ok := r.Context().Value(silenceSemWarnContextKey).(func()); ok {
-			silenceSemicolonsWarning()
-		}
 		if strings.Contains(r.URL.RawQuery, ";") {
 			r2 := new(Request)
 			*r2 = *r