chore: update to go1.21rc2, drop support for go1.19

component/dialer/control.go

@@ -20,3 +20,20 @@ func addControlToListenConfig(lc *net.ListenConfig, fn controlFn) {
 		return fn(context.Background(), network, address, c)
 	}
 }
+
+func addControlToDialer(d *net.Dialer, fn controlFn) {
+	ld := *d
+	d.ControlContext = func(ctx context.Context, network, address string, c syscall.RawConn) (err error) {
+		switch {
+		case ld.ControlContext != nil:
+			if err = ld.ControlContext(ctx, network, address, c); err != nil {
+				return
+			}
+		case ld.Control != nil:
+			if err = ld.Control(network, address, c); err != nil {
+				return
+			}
+		}
+		return fn(ctx, network, address, c)
+	}
+}

component/dialer/control_go119.go

@@ -1,22 +0,0 @@
-//go:build !go1.20
-
-package dialer
-
-import (
-	"context"
-	"net"
-	"syscall"
-)
-
-func addControlToDialer(d *net.Dialer, fn controlFn) {
-	ld := *d
-	d.Control = func(network, address string, c syscall.RawConn) (err error) {
-		switch {
-		case ld.Control != nil:
-			if err = ld.Control(network, address, c); err != nil {
-				return
-			}
-		}
-		return fn(context.Background(), network, address, c)
-	}
-}

component/dialer/control_go120.go

@@ -1,26 +0,0 @@
-//go:build go1.20
-
-package dialer
-
-import (
-	"context"
-	"net"
-	"syscall"
-)
-
-func addControlToDialer(d *net.Dialer, fn controlFn) {
-	ld := *d
-	d.ControlContext = func(ctx context.Context, network, address string, c syscall.RawConn) (err error) {
-		switch {
-		case ld.ControlContext != nil:
-			if err = ld.ControlContext(ctx, network, address, c); err != nil {
-				return
-			}
-		case ld.Control != nil:
-			if err = ld.Control(network, address, c); err != nil {
-				return
-			}
-		}
-		return fn(ctx, network, address, c)
-	}
-}

component/dialer/dialer.go

@@ -2,6 +2,7 @@ package dialer
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net"
 	"net/netip"
@@ -207,7 +208,7 @@ func dualStackDialContext(ctx context.Context, dialFn dialFunc, network string,
 	if fallback.error == nil && fallback.Conn != nil {
 		return fallback.Conn, nil
 	}
-	return nil, errorsJoin(errs...)
+	return nil, errors.Join(errs...)
 }
 
 func parallelDialContext(ctx context.Context, network string, ips []netip.Addr, port string, opt *option) (net.Conn, error) {
@@ -244,7 +245,7 @@ func parallelDialContext(ctx context.Context, network string, ips []netip.Addr,
 	}
 
 	if len(errs) > 0 {
-		return nil, errorsJoin(errs...)
+		return nil, errors.Join(errs...)
 	}
 	return nil, os.ErrDeadlineExceeded
 }
@@ -261,7 +262,7 @@ func serialDialContext(ctx context.Context, network string, ips []netip.Addr, po
 			errs = append(errs, err)
 		}
 	}
-	return nil, errorsJoin(errs...)
+	return nil, errors.Join(errs...)
 }
 
 type dialResult struct {

component/dialer/error.go

@@ -2,17 +2,9 @@ package dialer
 
 import (
 	"errors"
-
-	E "github.com/sagernet/sing/common/exceptions"
 )
 
 var (
 	ErrorNoIpAddress           = errors.New("no ip address")
 	ErrorInvalidedNetworkStack = errors.New("invalided network stack")
 )
-
-func errorsJoin(errs ...error) error {
-	// compatibility with golang<1.20
-	// maybe use errors.Join(errs...) is better after we drop the old version's support
-	return E.Errors(errs...)
-}