Gecko [ 167.86.127.34 ]

Name	Size	Permission
http	[ DIR ]	drwxr-xr-x
internal	[ DIR ]	drwxr-xr-x
mail	[ DIR ]	drwxr-xr-x
rpc	[ DIR ]	drwxr-xr-x
smtp	[ DIR ]	drwxr-xr-x
testdata	[ DIR ]	drwxr-xr-x
textproto	[ DIR ]	drwxr-xr-x
url	[ DIR ]	drwxr-xr-x
addrselect.go	9.51 KB	-rw-r--r--
addrselect_test.go	6.2 KB	-rw-r--r--
cgo_aix.go	578 B	-rw-r--r--
cgo_android.go	268 B	-rw-r--r--
cgo_bsd.go	348 B	-rw-r--r--
cgo_linux.go	635 B	-rw-r--r--
cgo_netbsd.go	272 B	-rw-r--r--
cgo_openbsd.go	272 B	-rw-r--r--
cgo_resnew.go	577 B	-rw-r--r--
cgo_resold.go	571 B	-rw-r--r--
cgo_socknew.go	748 B	-rw-r--r--
cgo_sockold.go	838 B	-rw-r--r--
cgo_solaris.go	339 B	-rw-r--r--
cgo_stub.go	1.06 KB	-rw-r--r--
cgo_unix.go	9.53 KB	-rw-r--r--
cgo_unix_test.go	1.89 KB	-rw-r--r--
cgo_windows.go	398 B	-rw-r--r--
conf.go	8.88 KB	-rw-r--r--
conf_netcgo.go	369 B	-rw-r--r--
conf_test.go	9.59 KB	-rw-r--r--
conn_test.go	1.77 KB	-rw-r--r--
dial.go	22.44 KB	-rw-r--r--
dial_test.go	27 KB	-rw-r--r--
dial_unix_test.go	2.74 KB	-rw-r--r--
dnsclient.go	5.34 KB	-rw-r--r--
dnsclient_test.go	1.54 KB	-rw-r--r--
dnsclient_unix.go	21.86 KB	-rw-r--r--
dnsclient_unix_test.go	45.17 KB	-rw-r--r--
dnsconfig_unix.go	5.47 KB	-rw-r--r--
dnsconfig_unix_test.go	6.73 KB	-rw-r--r--
dnsname_test.go	1.98 KB	-rw-r--r--
error_plan9.go	224 B	-rw-r--r--
error_plan9_test.go	398 B	-rw-r--r--
error_posix.go	583 B	-rw-r--r--
error_posix_test.go	980 B	-rw-r--r--
error_test.go	19.39 KB	-rw-r--r--
error_unix.go	421 B	-rw-r--r--
error_unix_test.go	672 B	-rw-r--r--
error_windows.go	355 B	-rw-r--r--
error_windows_test.go	483 B	-rw-r--r--
example_test.go	3.16 KB	-rw-r--r--
external_test.go	4.07 KB	-rw-r--r--
fd_plan9.go	3.56 KB	-rw-r--r--
fd_unix.go	7.36 KB	-rw-r--r--
fd_windows.go	6.49 KB	-rw-r--r--
file.go	1.69 KB	-rw-r--r--
file_plan9.go	2.68 KB	-rw-r--r--
file_stub.go	485 B	-rw-r--r--
file_test.go	6.53 KB	-rw-r--r--
file_unix.go	2.51 KB	-rw-r--r--
file_windows.go	521 B	-rw-r--r--
hook.go	628 B	-rw-r--r--
hook_plan9.go	283 B	-rw-r--r--
hook_unix.go	734 B	-rw-r--r--
hook_windows.go	875 B	-rw-r--r--
hosts.go	3.1 KB	-rw-r--r--
hosts_test.go	4.65 KB	-rw-r--r--
interface.go	7.14 KB	-rw-r--r--
interface_aix.go	4.41 KB	-rw-r--r--
interface_bsd.go	2.74 KB	-rw-r--r--
interface_bsd_test.go	1.42 KB	-rw-r--r--
interface_bsdvar.go	711 B	-rw-r--r--
interface_darwin.go	1.29 KB	-rw-r--r--
interface_freebsd.go	1.42 KB	-rw-r--r--
interface_linux.go	6.9 KB	-rw-r--r--
interface_linux_test.go	3.65 KB	-rw-r--r--
interface_plan9.go	4.59 KB	-rw-r--r--
interface_solaris.go	2.46 KB	-rw-r--r--
interface_stub.go	808 B	-rw-r--r--
interface_test.go	9.67 KB	-rw-r--r--
interface_unix_test.go	4.69 KB	-rw-r--r--
interface_windows.go	5.41 KB	-rw-r--r--
ip.go	16.61 KB	-rw-r--r--
ip_test.go	23.96 KB	-rw-r--r--
iprawsock.go	7.08 KB	-rw-r--r--
iprawsock_plan9.go	874 B	-rw-r--r--
iprawsock_posix.go	3.45 KB	-rw-r--r--
iprawsock_test.go	5.62 KB	-rw-r--r--
ipsock.go	8.77 KB	-rw-r--r--
ipsock_plan9.go	6.25 KB	-rw-r--r--
ipsock_posix.go	6.16 KB	-rw-r--r--
ipsock_test.go	6.81 KB	-rw-r--r--
listen_test.go	21.32 KB	-rw-r--r--
lookup.go	15.45 KB	-rw-r--r--
lookup_fake.go	1.64 KB	-rw-r--r--
lookup_plan9.go	7.68 KB	-rw-r--r--
lookup_test.go	29.14 KB	-rw-r--r--
lookup_unix.go	8.78 KB	-rw-r--r--
lookup_windows.go	11.74 KB	-rw-r--r--
lookup_windows_test.go	8 KB	-rw-r--r--
mac.go	1.88 KB	-rw-r--r--
mac_test.go	3.26 KB	-rw-r--r--
main_cloexec_test.go	669 B	-rw-r--r--
main_conf_test.go	915 B	-rw-r--r--
main_noconf_test.go	493 B	-rw-r--r--
main_plan9_test.go	392 B	-rw-r--r--
main_posix_test.go	1.37 KB	-rw-r--r--
main_test.go	7.11 KB	-rw-r--r--
main_unix_test.go	1.24 KB	-rw-r--r--
main_windows_test.go	1.08 KB	-rw-r--r--
mockserver_test.go	11.23 KB	-rw-r--r--
net.go	20.9 KB	-rw-r--r--
net_fake.go	5.34 KB	-rw-r--r--
net_test.go	12.1 KB	-rw-r--r--
net_windows_test.go	15.94 KB	-rw-r--r--
netgo_unix_test.go	631 B	-rw-r--r--
nss.go	3.71 KB	-rw-r--r--
nss_test.go	3.33 KB	-rw-r--r--
packetconn_test.go	3.56 KB	-rw-r--r--
parse.go	7.82 KB	-rw-r--r--
parse_test.go	2.14 KB	-rw-r--r--
pipe.go	5.59 KB	-rw-r--r--
pipe_test.go	1.2 KB	-rw-r--r--
platform_test.go	4.59 KB	-rw-r--r--
port.go	1.46 KB	-rw-r--r--
port_test.go	1.34 KB	-rw-r--r--
port_unix.go	1.28 KB	-rw-r--r--
protoconn_test.go	7.22 KB	-rw-r--r--
rawconn.go	1.89 KB	-rw-r--r--
rawconn_stub_test.go	622 B	-rw-r--r--
rawconn_test.go	4.52 KB	-rw-r--r--
rawconn_unix_test.go	3.15 KB	-rw-r--r--
rawconn_windows_test.go	3.26 KB	-rw-r--r--
sendfile_linux.go	1.1 KB	-rw-r--r--
sendfile_stub.go	329 B	-rw-r--r--
sendfile_test.go	5.69 KB	-rw-r--r--
sendfile_unix_alt.go	1.98 KB	-rw-r--r--
sendfile_windows.go	1.02 KB	-rw-r--r--
server_test.go	11.55 KB	-rw-r--r--
sock_bsd.go	898 B	-rw-r--r--
sock_cloexec.go	1.46 KB	-rw-r--r--
sock_linux.go	644 B	-rw-r--r--
sock_plan9.go	262 B	-rw-r--r--
sock_posix.go	6.83 KB	-rw-r--r--
sock_stub.go	378 B	-rw-r--r--
sock_windows.go	1.16 KB	-rw-r--r--
sockaddr_posix.go	955 B	-rw-r--r--
sockopt_aix.go	1.32 KB	-rw-r--r--
sockopt_bsd.go	2.09 KB	-rw-r--r--
sockopt_linux.go	1.14 KB	-rw-r--r--
sockopt_plan9.go	406 B	-rw-r--r--
sockopt_posix.go	2.67 KB	-rw-r--r--
sockopt_solaris.go	1.14 KB	-rw-r--r--
sockopt_stub.go	738 B	-rw-r--r--
sockopt_windows.go	1.34 KB	-rw-r--r--
sockoptip_bsdvar.go	848 B	-rw-r--r--
sockoptip_linux.go	735 B	-rw-r--r--
sockoptip_posix.go	1.43 KB	-rw-r--r--
sockoptip_stub.go	949 B	-rw-r--r--
sockoptip_windows.go	819 B	-rw-r--r--
splice_linux.go	1.09 KB	-rw-r--r--
splice_stub.go	286 B	-rw-r--r--
splice_test.go	10.51 KB	-rw-r--r--
sys_cloexec.go	977 B	-rw-r--r--
tcpsock.go	9.85 KB	-rw-r--r--
tcpsock_plan9.go	2.13 KB	-rw-r--r--
tcpsock_posix.go	5.27 KB	-rw-r--r--
tcpsock_test.go	17.51 KB	-rw-r--r--
tcpsock_unix_test.go	2.38 KB	-rw-r--r--
tcpsockopt_darwin.go	770 B	-rw-r--r--
tcpsockopt_dragonfly.go	698 B	-rw-r--r--
tcpsockopt_openbsd.go	365 B	-rw-r--r--
tcpsockopt_plan9.go	503 B	-rw-r--r--
tcpsockopt_posix.go	491 B	-rw-r--r--
tcpsockopt_solaris.go	1.15 KB	-rw-r--r--
tcpsockopt_stub.go	393 B	-rw-r--r--
tcpsockopt_unix.go	712 B	-rw-r--r--
tcpsockopt_windows.go	741 B	-rw-r--r--
timeout_test.go	23.18 KB	-rw-r--r--
udpsock.go	8.7 KB	-rw-r--r--
udpsock_plan9.go	3.77 KB	-rw-r--r--
udpsock_plan9_test.go	1.31 KB	-rw-r--r--
udpsock_posix.go	4.09 KB	-rw-r--r--
udpsock_test.go	11.18 KB	-rw-r--r--
unixsock.go	10.17 KB	-rw-r--r--
unixsock_linux_test.go	2.29 KB	-rw-r--r--
unixsock_plan9.go	1.24 KB	-rw-r--r--
unixsock_posix.go	5.81 KB	-rw-r--r--
unixsock_test.go	10.58 KB	-rw-r--r--
unixsock_windows_test.go	2.07 KB	-rw-r--r--
write_unix_test.go	1.59 KB	-rw-r--r--
writev_test.go	5.01 KB	-rw-r--r--
writev_unix.go	706 B	-rw-r--r--

Code Editor : error_test.go

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build !js

package net

import (
	"context"
	"fmt"
	"internal/poll"
	"io"
	"io/ioutil"
	"net/internal/socktest"
	"os"
	"runtime"
	"strings"
	"testing"
	"time"
)

func (e *OpError) isValid() error {
	if e.Op == "" {
		return fmt.Errorf("OpError.Op is empty: %v", e)
	}
	if e.Net == "" {
		return fmt.Errorf("OpError.Net is empty: %v", e)
	}
	for _, addr := range []Addr{e.Source, e.Addr} {
		switch addr := addr.(type) {
		case nil:
		case *TCPAddr:
			if addr == nil {
				return fmt.Errorf("OpError.Source or Addr is non-nil interface: %#v, %v", addr, e)
			}
		case *UDPAddr:
			if addr == nil {
				return fmt.Errorf("OpError.Source or Addr is non-nil interface: %#v, %v", addr, e)
			}
		case *IPAddr:
			if addr == nil {
				return fmt.Errorf("OpError.Source or Addr is non-nil interface: %#v, %v", addr, e)
			}
		case *IPNet:
			if addr == nil {
				return fmt.Errorf("OpError.Source or Addr is non-nil interface: %#v, %v", addr, e)
			}
		case *UnixAddr:
			if addr == nil {
				return fmt.Errorf("OpError.Source or Addr is non-nil interface: %#v, %v", addr, e)
			}
		case *pipeAddr:
			if addr == nil {
				return fmt.Errorf("OpError.Source or Addr is non-nil interface: %#v, %v", addr, e)
			}
		case fileAddr:
			if addr == "" {
				return fmt.Errorf("OpError.Source or Addr is empty: %#v, %v", addr, e)
			}
		default:
			return fmt.Errorf("OpError.Source or Addr is unknown type: %T, %v", addr, e)
		}
	}
	if e.Err == nil {
		return fmt.Errorf("OpError.Err is empty: %v", e)
	}
	return nil
}

// parseDialError parses nestedErr and reports whether it is a valid
// error value from Dial, Listen functions.
// It returns nil when nestedErr is valid.
func parseDialError(nestedErr error) error {
	if nestedErr == nil {
		return nil
	}

switch err := nestedErr.(type) {
	case *OpError:
		if err := err.isValid(); err != nil {
			return err
		}
		nestedErr = err.Err
		goto second
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

second:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch err := nestedErr.(type) {
	case *AddrError, addrinfoErrno, *DNSError, InvalidAddrError, *ParseError, *poll.TimeoutError, UnknownNetworkError:
		return nil
	case *os.SyscallError:
		nestedErr = err.Err
		goto third
	case *os.PathError: // for Plan 9
		nestedErr = err.Err
		goto third
	}
	switch nestedErr {
	case errCanceled, poll.ErrNetClosing, errMissingAddress, errNoSuitableAddress,
		context.DeadlineExceeded, context.Canceled:
		return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

third:
	if isPlatformError(nestedErr) {
		return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
}

var dialErrorTests = []struct {
	network, address string
}{
	{"foo", ""},
	{"bar", "baz"},
	{"datakit", "mh/astro/r70"},
	{"tcp", ""},
	{"tcp", "127.0.0.1:☺"},
	{"tcp", "no-such-name:80"},
	{"tcp", "mh/astro/r70:http"},

{"tcp", JoinHostPort("127.0.0.1", "-1")},
	{"tcp", JoinHostPort("127.0.0.1", "123456789")},
	{"udp", JoinHostPort("127.0.0.1", "-1")},
	{"udp", JoinHostPort("127.0.0.1", "123456789")},
	{"ip:icmp", "127.0.0.1"},

{"unix", "/path/to/somewhere"},
	{"unixgram", "/path/to/somewhere"},
	{"unixpacket", "/path/to/somewhere"},
}

func TestDialError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = func(ctx context.Context, fn func(context.Context, string, string) ([]IPAddr, error), network, host string) ([]IPAddr, error) {
		return nil, &DNSError{Err: "dial error test", Name: "name", Server: "server", IsTimeout: true}
	}
	sw.Set(socktest.FilterConnect, func(so *socktest.Status) (socktest.AfterFilter, error) {
		return nil, errOpNotSupported
	})
	defer sw.Set(socktest.FilterConnect, nil)

d := Dialer{Timeout: someTimeout}
	for i, tt := range dialErrorTests {
		c, err := d.Dial(tt.network, tt.address)
		if err == nil {
			t.Errorf("#%d: should fail; %s:%s->%s", i, c.LocalAddr().Network(), c.LocalAddr(), c.RemoteAddr())
			c.Close()
			continue
		}
		if tt.network == "tcp" || tt.network == "udp" {
			nerr := err
			if op, ok := nerr.(*OpError); ok {
				nerr = op.Err
			}
			if sys, ok := nerr.(*os.SyscallError); ok {
				nerr = sys.Err
			}
			if nerr == errOpNotSupported {
				t.Errorf("#%d: should fail without %v; %s:%s->", i, nerr, tt.network, tt.address)
				continue
			}
		}
		if c != nil {
			t.Errorf("Dial returned non-nil interface %T(%v) with err != nil", c, c)
		}
		if err = parseDialError(err); err != nil {
			t.Errorf("#%d: %v", i, err)
			continue
		}
	}
}

func TestProtocolDialError(t *testing.T) {
	switch runtime.GOOS {
	case "solaris", "illumos":
		t.Skipf("not supported on %s", runtime.GOOS)
	}

for _, network := range []string{"tcp", "udp", "ip:4294967296", "unix", "unixpacket", "unixgram"} {
		var err error
		switch network {
		case "tcp":
			_, err = DialTCP(network, nil, &TCPAddr{Port: 1 << 16})
		case "udp":
			_, err = DialUDP(network, nil, &UDPAddr{Port: 1 << 16})
		case "ip:4294967296":
			_, err = DialIP(network, nil, nil)
		case "unix", "unixpacket", "unixgram":
			_, err = DialUnix(network, nil, &UnixAddr{Name: "//"})
		}
		if err == nil {
			t.Errorf("%s: should fail", network)
			continue
		}
		if err = parseDialError(err); err != nil {
			t.Errorf("%s: %v", network, err)
			continue
		}
	}
}

func TestDialAddrError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv4() || !supportsIPv6() {
		t.Skip("both IPv4 and IPv6 are required")
	}

for _, tt := range []struct {
		network string
		lit     string
		addr    *TCPAddr
	}{
		{"tcp4", "::1", nil},
		{"tcp4", "", &TCPAddr{IP: IPv6loopback}},
		// We don't test the {"tcp6", "byte sequence", nil}
		// case for now because there is no easy way to
		// control name resolution.
		{"tcp6", "", &TCPAddr{IP: IP{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}}},
	} {
		var err error
		var c Conn
		var op string
		if tt.lit != "" {
			c, err = Dial(tt.network, JoinHostPort(tt.lit, "0"))
			op = fmt.Sprintf("Dial(%q, %q)", tt.network, JoinHostPort(tt.lit, "0"))
		} else {
			c, err = DialTCP(tt.network, nil, tt.addr)
			op = fmt.Sprintf("DialTCP(%q, %q)", tt.network, tt.addr)
		}
		if err == nil {
			c.Close()
			t.Errorf("%s succeeded, want error", op)
			continue
		}
		if perr := parseDialError(err); perr != nil {
			t.Errorf("%s: %v", op, perr)
			continue
		}
		operr := err.(*OpError).Err
		aerr, ok := operr.(*AddrError)
		if !ok {
			t.Errorf("%s: %v is %T, want *AddrError", op, err, operr)
			continue
		}
		want := tt.lit
		if tt.lit == "" {
			want = tt.addr.IP.String()
		}
		if aerr.Addr != want {
			t.Errorf("%s: %v, error Addr=%q, want %q", op, err, aerr.Addr, want)
		}
	}
}

var listenErrorTests = []struct {
	network, address string
}{
	{"foo", ""},
	{"bar", "baz"},
	{"datakit", "mh/astro/r70"},
	{"tcp", "127.0.0.1:☺"},
	{"tcp", "no-such-name:80"},
	{"tcp", "mh/astro/r70:http"},

{"tcp", JoinHostPort("127.0.0.1", "-1")},
	{"tcp", JoinHostPort("127.0.0.1", "123456789")},

{"unix", "/path/to/somewhere"},
	{"unixpacket", "/path/to/somewhere"},
}

func TestListenError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = func(_ context.Context, fn func(context.Context, string, string) ([]IPAddr, error), network, host string) ([]IPAddr, error) {
		return nil, &DNSError{Err: "listen error test", Name: "name", Server: "server", IsTimeout: true}
	}
	sw.Set(socktest.FilterListen, func(so *socktest.Status) (socktest.AfterFilter, error) {
		return nil, errOpNotSupported
	})
	defer sw.Set(socktest.FilterListen, nil)

for i, tt := range listenErrorTests {
		ln, err := Listen(tt.network, tt.address)
		if err == nil {
			t.Errorf("#%d: should fail; %s:%s->", i, ln.Addr().Network(), ln.Addr())
			ln.Close()
			continue
		}
		if tt.network == "tcp" {
			nerr := err
			if op, ok := nerr.(*OpError); ok {
				nerr = op.Err
			}
			if sys, ok := nerr.(*os.SyscallError); ok {
				nerr = sys.Err
			}
			if nerr == errOpNotSupported {
				t.Errorf("#%d: should fail without %v; %s:%s->", i, nerr, tt.network, tt.address)
				continue
			}
		}
		if ln != nil {
			t.Errorf("Listen returned non-nil interface %T(%v) with err != nil", ln, ln)
		}
		if err = parseDialError(err); err != nil {
			t.Errorf("#%d: %v", i, err)
			continue
		}
	}
}

var listenPacketErrorTests = []struct {
	network, address string
}{
	{"foo", ""},
	{"bar", "baz"},
	{"datakit", "mh/astro/r70"},
	{"udp", "127.0.0.1:☺"},
	{"udp", "no-such-name:80"},
	{"udp", "mh/astro/r70:http"},

{"udp", JoinHostPort("127.0.0.1", "-1")},
	{"udp", JoinHostPort("127.0.0.1", "123456789")},
}

func TestListenPacketError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

for i, tt := range listenPacketErrorTests {
		c, err := ListenPacket(tt.network, tt.address)
		if err == nil {
			t.Errorf("#%d: should fail; %s:%s->", i, c.LocalAddr().Network(), c.LocalAddr())
			c.Close()
			continue
		}
		if c != nil {
			t.Errorf("ListenPacket returned non-nil interface %T(%v) with err != nil", c, c)
		}
		if err = parseDialError(err); err != nil {
			t.Errorf("#%d: %v", i, err)
			continue
		}
	}
}

func TestProtocolListenError(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("not supported on %s", runtime.GOOS)
	}

for _, network := range []string{"tcp", "udp", "ip:4294967296", "unix", "unixpacket", "unixgram"} {
		var err error
		switch network {
		case "tcp":
			_, err = ListenTCP(network, &TCPAddr{Port: 1 << 16})
		case "udp":
			_, err = ListenUDP(network, &UDPAddr{Port: 1 << 16})
		case "ip:4294967296":
			_, err = ListenIP(network, nil)
		case "unix", "unixpacket":
			_, err = ListenUnix(network, &UnixAddr{Name: "//"})
		case "unixgram":
			_, err = ListenUnixgram(network, &UnixAddr{Name: "//"})
		}
		if err == nil {
			t.Errorf("%s: should fail", network)
			continue
		}
		if err = parseDialError(err); err != nil {
			t.Errorf("%s: %v", network, err)
			continue
		}
	}
}

// parseReadError parses nestedErr and reports whether it is a valid
// error value from Read functions.
// It returns nil when nestedErr is valid.
func parseReadError(nestedErr error) error {
	if nestedErr == nil {
		return nil
	}

switch err := nestedErr.(type) {
	case *OpError:
		if err := err.isValid(); err != nil {
			return err
		}
		nestedErr = err.Err
		goto second
	}
	if nestedErr == io.EOF {
		return nil
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)

second:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
		nestedErr = err.Err
		goto third
	}
	switch nestedErr {
	case poll.ErrNetClosing, poll.ErrTimeout, poll.ErrNotPollable:
		return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

third:
	if isPlatformError(nestedErr) {
		return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
}

// parseWriteError parses nestedErr and reports whether it is a valid
// error value from Write functions.
// It returns nil when nestedErr is valid.
func parseWriteError(nestedErr error) error {
	if nestedErr == nil {
		return nil
	}

second:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch err := nestedErr.(type) {
	case *AddrError, addrinfoErrno, *DNSError, InvalidAddrError, *ParseError, *poll.TimeoutError, UnknownNetworkError:
		return nil
	case *os.SyscallError:
		nestedErr = err.Err
		goto third
	}
	switch nestedErr {
	case errCanceled, poll.ErrNetClosing, errMissingAddress, poll.ErrTimeout, ErrWriteToConnected, io.ErrUnexpectedEOF:
		return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

third:
	if isPlatformError(nestedErr) {
		return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
}

// parseCloseError parses nestedErr and reports whether it is a valid
// error value from Close functions.
// It returns nil when nestedErr is valid.
func parseCloseError(nestedErr error, isShutdown bool) error {
	if nestedErr == nil {
		return nil
	}

// Because historically we have not exported the error that we
	// return for an operation on a closed network connection,
	// there are programs that test for the exact error string.
	// Verify that string here so that we don't break those
	// programs unexpectedly. See issues #4373 and #19252.
	want := "use of closed network connection"
	if !isShutdown && !strings.Contains(nestedErr.Error(), want) {
		return fmt.Errorf("error string %q does not contain expected string %q", nestedErr, want)
	}

second:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
		nestedErr = err.Err
		goto third
	case *os.PathError: // for Plan 9
		nestedErr = err.Err
		goto third
	}
	switch nestedErr {
	case poll.ErrNetClosing:
		return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

third:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch nestedErr {
	case os.ErrClosed: // for Plan 9
		return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
}

func TestCloseError(t *testing.T) {
	ln, err := newLocalListener("tcp")
	if err != nil {
		t.Fatal(err)
	}
	defer ln.Close()
	c, err := Dial(ln.Addr().Network(), ln.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()

for i := 0; i < 3; i++ {
		err = c.(*TCPConn).CloseRead()
		if perr := parseCloseError(err, true); perr != nil {
			t.Errorf("#%d: %v", i, perr)
		}
	}
	for i := 0; i < 3; i++ {
		err = c.(*TCPConn).CloseWrite()
		if perr := parseCloseError(err, true); perr != nil {
			t.Errorf("#%d: %v", i, perr)
		}
	}
	for i := 0; i < 3; i++ {
		err = c.Close()
		if perr := parseCloseError(err, false); perr != nil {
			t.Errorf("#%d: %v", i, perr)
		}
		err = ln.Close()
		if perr := parseCloseError(err, false); perr != nil {
			t.Errorf("#%d: %v", i, perr)
		}
	}

pc, err := ListenPacket("udp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	defer pc.Close()

for i := 0; i < 3; i++ {
		err = pc.Close()
		if perr := parseCloseError(err, false); perr != nil {
			t.Errorf("#%d: %v", i, perr)
		}
	}
}

// parseAcceptError parses nestedErr and reports whether it is a valid
// error value from Accept functions.
// It returns nil when nestedErr is valid.
func parseAcceptError(nestedErr error) error {
	if nestedErr == nil {
		return nil
	}

second:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
		nestedErr = err.Err
		goto third
	case *os.PathError: // for Plan 9
		nestedErr = err.Err
		goto third
	}
	switch nestedErr {
	case poll.ErrNetClosing, poll.ErrTimeout, poll.ErrNotPollable:
		return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

third:
	if isPlatformError(nestedErr) {
		return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
}

func TestAcceptError(t *testing.T) {
	handler := func(ls *localServer, ln Listener) {
		for {
			ln.(*TCPListener).SetDeadline(time.Now().Add(5 * time.Millisecond))
			c, err := ln.Accept()
			if perr := parseAcceptError(err); perr != nil {
				t.Error(perr)
			}
			if err != nil {
				if c != nil {
					t.Errorf("Accept returned non-nil interface %T(%v) with err != nil", c, c)
				}
				if nerr, ok := err.(Error); !ok || (!nerr.Timeout() && !nerr.Temporary()) {
					return
				}
				continue
			}
			c.Close()
		}
	}
	ls, err := newLocalServer("tcp")
	if err != nil {
		t.Fatal(err)
	}
	if err := ls.buildup(handler); err != nil {
		ls.teardown()
		t.Fatal(err)
	}

time.Sleep(100 * time.Millisecond)
	ls.teardown()
}

// parseCommonError parses nestedErr and reports whether it is a valid
// error value from miscellaneous functions.
// It returns nil when nestedErr is valid.
func parseCommonError(nestedErr error) error {
	if nestedErr == nil {
		return nil
	}

second:
	if isPlatformError(nestedErr) {
		return nil
	}
	switch err := nestedErr.(type) {
	case *os.SyscallError:
		nestedErr = err.Err
		goto third
	case *os.LinkError:
		nestedErr = err.Err
		goto third
	case *os.PathError:
		nestedErr = err.Err
		goto third
	}
	switch nestedErr {
	case poll.ErrNetClosing:
		return nil
	}
	return fmt.Errorf("unexpected type on 2nd nested level: %T", nestedErr)

third:
	if isPlatformError(nestedErr) {
		return nil
	}
	return fmt.Errorf("unexpected type on 3rd nested level: %T", nestedErr)
}

func TestFileError(t *testing.T) {
	switch runtime.GOOS {
	case "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}

f, err := ioutil.TempFile("", "go-nettest")
	if err != nil {
		t.Fatal(err)
	}
	defer os.Remove(f.Name())
	defer f.Close()

c, err := FileConn(f)
	if err != nil {
		if c != nil {
			t.Errorf("FileConn returned non-nil interface %T(%v) with err != nil", c, c)
		}
		if perr := parseCommonError(err); perr != nil {
			t.Error(perr)
		}
	} else {
		c.Close()
		t.Error("should fail")
	}
	ln, err := FileListener(f)
	if err != nil {
		if ln != nil {
			t.Errorf("FileListener returned non-nil interface %T(%v) with err != nil", ln, ln)
		}
		if perr := parseCommonError(err); perr != nil {
			t.Error(perr)
		}
	} else {
		ln.Close()
		t.Error("should fail")
	}
	pc, err := FilePacketConn(f)
	if err != nil {
		if pc != nil {
			t.Errorf("FilePacketConn returned non-nil interface %T(%v) with err != nil", pc, pc)
		}
		if perr := parseCommonError(err); perr != nil {
			t.Error(perr)
		}
	} else {
		pc.Close()
		t.Error("should fail")
	}

ln, err = newLocalListener("tcp")
	if err != nil {
		t.Fatal(err)
	}

for i := 0; i < 3; i++ {
		f, err := ln.(*TCPListener).File()
		if err != nil {
			if perr := parseCommonError(err); perr != nil {
				t.Error(perr)
			}
		} else {
			f.Close()
		}
		ln.Close()
	}
}

func parseLookupPortError(nestedErr error) error {
	if nestedErr == nil {
		return nil
	}

switch nestedErr.(type) {
	case *AddrError, *DNSError:
		return nil
	case *os.PathError: // for Plan 9
		return nil
	}
	return fmt.Errorf("unexpected type on 1st nested level: %T", nestedErr)
}

${this.title}

Code Editor : error_test.go