We cannot avoid continuing to call SetReadDeadline and similar method…

…s after the connection is closed. (#1835)

In the current implementation, there are several places where it's assumed that SetReadDeadline and similar functions logically won't affect a closed connection. However, these assumptions may not hold in certain specific situations. Therefore, instead of asserting that such errors will never occur, simply return the errors encountered during the execution of these methods.

server.go

@@ -1597,14 +1597,14 @@ func (s *Server) NextProto(key string, nph ServeHandler) {
 func (s *Server) getNextProto(c net.Conn) (proto string, err error) {
 	if tlsConn, ok := c.(connTLSer); ok {
 		if s.ReadTimeout > 0 {
-			if err := c.SetReadDeadline(time.Now().Add(s.ReadTimeout)); err != nil {
-				panic(fmt.Sprintf("BUG: error in SetReadDeadline(%v): %v", s.ReadTimeout, err))
+			if err = c.SetReadDeadline(time.Now().Add(s.ReadTimeout)); err != nil {
+				return
 			}
 		}
 
 		if s.WriteTimeout > 0 {
-			if err := c.SetWriteDeadline(time.Now().Add(s.WriteTimeout)); err != nil {
-				panic(fmt.Sprintf("BUG: error in SetWriteDeadline(%v): %v", s.WriteTimeout, err))
+			if err = c.SetWriteDeadline(time.Now().Add(s.WriteTimeout)); err != nil {
+				return
 			}
 		}
 
@@ -2137,8 +2137,8 @@ func (s *Server) serveConn(c net.Conn) (err error) {
 		// Remove read or write deadlines that might have previously been set.
 		// The next handler is responsible for setting its own deadlines.
 		if s.ReadTimeout > 0 || s.WriteTimeout > 0 {
-			if err := c.SetDeadline(zeroTime); err != nil {
-				panic(fmt.Sprintf("BUG: error in SetDeadline(zeroTime): %v", err))
+			if err = c.SetDeadline(zeroTime); err != nil {
+				return
 			}
 		}
 
@@ -2177,7 +2177,7 @@ func (s *Server) serveConn(c net.Conn) (err error) {
 		// If this is a keep-alive connection set the idle timeout.
 		if connRequestNum > 1 {
 			if d := s.idleTimeout(); d > 0 {
-				if err := c.SetReadDeadline(time.Now().Add(d)); err != nil {
+				if err = c.SetReadDeadline(time.Now().Add(d)); err != nil {
 					break
 				}
 			}
@@ -2221,13 +2221,13 @@ func (s *Server) serveConn(c net.Conn) (err error) {
 			s.setState(c, StateActive)
 
 			if s.ReadTimeout > 0 {
-				if err := c.SetReadDeadline(time.Now().Add(s.ReadTimeout)); err != nil {
+				if err = c.SetReadDeadline(time.Now().Add(s.ReadTimeout)); err != nil {
 					break
 				}
 			} else if s.IdleTimeout > 0 && connRequestNum > 1 {
 				// If this was an idle connection and the server has an IdleTimeout but
 				// no ReadTimeout then we should remove the ReadTimeout.
-				if err := c.SetReadDeadline(zeroTime); err != nil {
+				if err = c.SetReadDeadline(zeroTime); err != nil {
 					break
 				}
 			}
@@ -2261,8 +2261,8 @@ func (s *Server) serveConn(c net.Conn) (err error) {
 					reqConf := onHdrRecv(&ctx.Request.Header)
 					if reqConf.ReadTimeout > 0 {
 						deadline := time.Now().Add(reqConf.ReadTimeout)
-						if err := c.SetReadDeadline(deadline); err != nil {
-							panic(fmt.Sprintf("BUG: error in SetReadDeadline(%v): %v", deadline, err))
+						if err = c.SetReadDeadline(deadline); err != nil {
+							break
 						}
 					}
 					switch {
@@ -2401,14 +2401,14 @@ func (s *Server) serveConn(c net.Conn) (err error) {
 		ctx.hijackNoResponse = false
 
 		if writeTimeout > 0 {
-			if err := c.SetWriteDeadline(time.Now().Add(writeTimeout)); err != nil {
-				panic(fmt.Sprintf("BUG: error in SetWriteDeadline(%v): %v", writeTimeout, err))
+			if err = c.SetWriteDeadline(time.Now().Add(writeTimeout)); err != nil {
+				break
 			}
 			previousWriteTimeout = writeTimeout
 		} else if previousWriteTimeout > 0 {
 			// We don't want a write timeout but we previously set one, remove it.
-			if err := c.SetWriteDeadline(zeroTime); err != nil {
-				panic(fmt.Sprintf("BUG: error in SetWriteDeadline(zeroTime): %v", err))
+			if err = c.SetWriteDeadline(zeroTime); err != nil {
+				break
 			}
 			previousWriteTimeout = 0
 		}