net: enable most tests on wasip1 and js

To get them to pass, implement more fake syscalls.
To make those syscalls easier to reason about, replace
the use of sync.Cond with selectable channels.

Fixes #59718.
Fixes #50216.

Change-Id: I135a6656f5c48f0e5c43dc4d4bcbdb48ee5535d2
Reviewed-on: https://go-review.googlesource.com/c/go/+/526117
Run-TryBot: Bryan Mills <[email protected]>
Reviewed-by: Johan Brandhorst-Satzkorn <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Reviewed-by: Achille Roussel <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: Bryan C. Mills

src/net/cgo_stub.go

@@ -9,7 +9,7 @@
 //   (Darwin always provides the cgo functions, in cgo_unix_syscall.go)
 // - on wasip1, where cgo is never available
 
-//go:build (netgo && unix) || (unix && !cgo && !darwin) || wasip1
+//go:build (netgo && unix) || (unix && !cgo && !darwin) || js || wasip1
 
 package net
 

src/net/conf.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !js
-
 package net
 
 import (

src/net/conn_test.go

@@ -2,10 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// This file implements API tests across platforms and will never have a build
-// tag.
-
-//go:build !js && !wasip1
+// This file implements API tests across platforms and should never have a build
+// constraint.
 
 package net
 
@@ -21,44 +19,46 @@ const someTimeout = 1 * time.Hour
 
 func TestConnAndListener(t *testing.T) {
 	for i, network := range []string{"tcp", "unix", "unixpacket"} {
-		if !testableNetwork(network) {
-			t.Logf("skipping %s test", network)
-			continue
-		}
+		i, network := i, network
+		t.Run(network, func(t *testing.T) {
+			if !testableNetwork(network) {
+				t.Skipf("skipping %s test", network)
+			}
 
-		ls := newLocalServer(t, network)
-		defer ls.teardown()
-		ch := make(chan error, 1)
-		handler := func(ls *localServer, ln Listener) { ls.transponder(ln, ch) }
-		if err := ls.buildup(handler); err != nil {
-			t.Fatal(err)
-		}
-		if ls.Listener.Addr().Network() != network {
-			t.Fatalf("got %s; want %s", ls.Listener.Addr().Network(), network)
-		}
+			ls := newLocalServer(t, network)
+			defer ls.teardown()
+			ch := make(chan error, 1)
+			handler := func(ls *localServer, ln Listener) { ls.transponder(ln, ch) }
+			if err := ls.buildup(handler); err != nil {
+				t.Fatal(err)
+			}
+			if ls.Listener.Addr().Network() != network {
+				t.Fatalf("got %s; want %s", ls.Listener.Addr().Network(), network)
+			}
 
-		c, err := Dial(ls.Listener.Addr().Network(), ls.Listener.Addr().String())
-		if err != nil {
-			t.Fatal(err)
-		}
-		defer c.Close()
-		if c.LocalAddr().Network() != network || c.RemoteAddr().Network() != network {
-			t.Fatalf("got %s->%s; want %s->%s", c.LocalAddr().Network(), c.RemoteAddr().Network(), network, network)
-		}
-		c.SetDeadline(time.Now().Add(someTimeout))
-		c.SetReadDeadline(time.Now().Add(someTimeout))
-		c.SetWriteDeadline(time.Now().Add(someTimeout))
+			c, err := Dial(ls.Listener.Addr().Network(), ls.Listener.Addr().String())
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer c.Close()
+			if c.LocalAddr().Network() != network || c.RemoteAddr().Network() != network {
+				t.Fatalf("got %s->%s; want %s->%s", c.LocalAddr().Network(), c.RemoteAddr().Network(), network, network)
+			}
+			c.SetDeadline(time.Now().Add(someTimeout))
+			c.SetReadDeadline(time.Now().Add(someTimeout))
+			c.SetWriteDeadline(time.Now().Add(someTimeout))
 
-		if _, err := c.Write([]byte("CONN AND LISTENER TEST")); err != nil {
-			t.Fatal(err)
-		}
-		rb := make([]byte, 128)
-		if _, err := c.Read(rb); err != nil {
-			t.Fatal(err)
-		}
+			if _, err := c.Write([]byte("CONN AND LISTENER TEST")); err != nil {
+				t.Fatal(err)
+			}
+			rb := make([]byte, 128)
+			if _, err := c.Read(rb); err != nil {
+				t.Fatal(err)
+			}
 
-		for err := range ch {
-			t.Errorf("#%d: %v", i, err)
-		}
+			for err := range ch {
+				t.Errorf("#%d: %v", i, err)
+			}
+		})
 	}
 }

src/net/dial_test.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !js && !wasip1
-
 package net
 
 import (
@@ -983,6 +981,8 @@ func TestDialerControl(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
 		t.Skipf("not supported on %s", runtime.GOOS)
+	case "js", "wasip1":
+		t.Skipf("skipping: fake net does not support Dialer.Control")
 	}
 
 	t.Run("StreamDial", func(t *testing.T) {
@@ -1026,28 +1026,32 @@ func TestDialerControlContext(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
 		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
+	case "js", "wasip1":
+		t.Skipf("skipping: fake net does not support Dialer.ControlContext")
 	}
 	t.Run("StreamDial", func(t *testing.T) {
 		for i, network := range []string{"tcp", "tcp4", "tcp6", "unix", "unixpacket"} {
-			if !testableNetwork(network) {
-				continue
-			}
-			ln := newLocalListener(t, network)
-			defer ln.Close()
-			var id int
-			d := Dialer{ControlContext: func(ctx context.Context, network string, address string, c syscall.RawConn) error {
-				id = ctx.Value("id").(int)
-				return controlOnConnSetup(network, address, c)
-			}}
-			c, err := d.DialContext(context.WithValue(context.Background(), "id", i+1), network, ln.Addr().String())
-			if err != nil {
-				t.Error(err)
-				continue
-			}
-			if id != i+1 {
-				t.Errorf("got id %d, want %d", id, i+1)
-			}
-			c.Close()
+			t.Run(network, func(t *testing.T) {
+				if !testableNetwork(network) {
+					t.Skipf("skipping: %s not available", network)
+				}
+
+				ln := newLocalListener(t, network)
+				defer ln.Close()
+				var id int
+				d := Dialer{ControlContext: func(ctx context.Context, network string, address string, c syscall.RawConn) error {
+					id = ctx.Value("id").(int)
+					return controlOnConnSetup(network, address, c)
+				}}
+				c, err := d.DialContext(context.WithValue(context.Background(), "id", i+1), network, ln.Addr().String())
+				if err != nil {
+					t.Fatal(err)
+				}
+				if id != i+1 {
+					t.Errorf("got id %d, want %d", id, i+1)
+				}
+				c.Close()
+			})
 		}
 	})
 }
@@ -1059,7 +1063,8 @@ func mustHaveExternalNetwork(t *testing.T) {
 	t.Helper()
 	definitelyHasLongtestBuilder := runtime.GOOS == "linux"
 	mobile := runtime.GOOS == "android" || runtime.GOOS == "ios"
-	if testenv.Builder() != "" && !definitelyHasLongtestBuilder && !mobile {
+	fake := runtime.GOOS == "js" || runtime.GOOS == "wasip1"
+	if testenv.Builder() != "" && !definitelyHasLongtestBuilder && !mobile && !fake {
 		// On a non-Linux, non-mobile builder (e.g., freebsd-amd64-13_0).
 		//
 		// Don't skip testing because otherwise the test may never run on

src/net/dnsclient_unix.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !js
-
 // DNS client: see RFC 1035.
 // Has to be linked into package net for Dial.
 

src/net/dnsconfig_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !js && !windows
+//go:build !windows
 
 // Read system DNS config from /etc/resolv.conf
 

src/net/dnsname_test.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !js && !wasip1
-
 package net
 
 import (

src/net/error_posix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build unix || (js && wasm) || wasip1 || windows
+//go:build unix || js || wasip1 || windows
 
 package net