util/uniq,types/lazy,*: delete code that's now in Go std

sync.OnceValue and slices.Compact were both added in Go 1.21.

cmp.Or was added in Go 1.22.

Updates tailscale#8632
Updates tailscale#11058

Change-Id: I89ba4c404f40188e1f8a9566c8aaa049be377754
Signed-off-by: Brad Fitzpatrick <[email protected]>

Author: bradfitz

cmd/k8s-operator/depaware.txt

@@ -817,7 +817,6 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
         tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+
         tailscale.com/util/testenv                                   from tailscale.com/control/controlclient+
         tailscale.com/util/truncate                                  from tailscale.com/logtail
-        tailscale.com/util/uniq                                      from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/usermetric                                from tailscale.com/health+
         tailscale.com/util/vizerror                                  from tailscale.com/tailcfg+
      💣 tailscale.com/util/winutil                                   from tailscale.com/clientupdate+

cmd/tailscaled/depaware.txt

@@ -406,7 +406,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+
         tailscale.com/util/testenv                                   from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/truncate                                  from tailscale.com/logtail
-        tailscale.com/util/uniq                                      from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/usermetric                                from tailscale.com/health+
         tailscale.com/util/vizerror                                  from tailscale.com/tailcfg+
      💣 tailscale.com/util/winutil                                   from tailscale.com/clientupdate+

ipn/ipnlocal/local.go

@@ -111,7 +111,6 @@ import (
 	"tailscale.com/util/syspolicy/rsop"
 	"tailscale.com/util/systemd"
 	"tailscale.com/util/testenv"
-	"tailscale.com/util/uniq"
 	"tailscale.com/util/usermetric"
 	"tailscale.com/version"
 	"tailscale.com/version/distro"
@@ -3346,7 +3345,7 @@ func (b *LocalBackend) clearMachineKeyLocked() error {
 // incoming packet.
 func (b *LocalBackend) setTCPPortsIntercepted(ports []uint16) {
 	slices.Sort(ports)
-	uniq.ModifySlice(&ports)
+	ports = slices.Compact(ports)
 	var f func(uint16) bool
 	switch len(ports) {
 	case 0:

ipn/localapi/debugderp.go

@@ -4,6 +4,7 @@
 package localapi
 
 import (
+	"cmp"
 	"context"
 	"crypto/tls"
 	"encoding/json"
@@ -81,15 +82,15 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 		client *http.Client = http.DefaultClient
 	)
 	checkConn := func(derpNode *tailcfg.DERPNode) bool {
-		port := firstNonzero(derpNode.DERPPort, 443)
+		port := cmp.Or(derpNode.DERPPort, 443)
 
 		var (
 			hasIPv4 bool
 			hasIPv6 bool
 		)
 
 		// Check IPv4 first
-		addr := net.JoinHostPort(firstNonzero(derpNode.IPv4, derpNode.HostName), strconv.Itoa(port))
+		addr := net.JoinHostPort(cmp.Or(derpNode.IPv4, derpNode.HostName), strconv.Itoa(port))
 		conn, err := dialer.DialContext(ctx, "tcp4", addr)
 		if err != nil {
 			st.Errors = append(st.Errors, fmt.Sprintf("Error connecting to node %q @ %q over IPv4: %v", derpNode.HostName, addr, err))
@@ -98,7 +99,7 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 
 			// Upgrade to TLS and verify that works properly.
 			tlsConn := tls.Client(conn, &tls.Config{
-				ServerName: firstNonzero(derpNode.CertName, derpNode.HostName),
+				ServerName: cmp.Or(derpNode.CertName, derpNode.HostName),
 			})
 			if err := tlsConn.HandshakeContext(ctx); err != nil {
 				st.Errors = append(st.Errors, fmt.Sprintf("Error upgrading connection to node %q @ %q to TLS over IPv4: %v", derpNode.HostName, addr, err))
@@ -108,7 +109,7 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 		}
 
 		// Check IPv6
-		addr = net.JoinHostPort(firstNonzero(derpNode.IPv6, derpNode.HostName), strconv.Itoa(port))
+		addr = net.JoinHostPort(cmp.Or(derpNode.IPv6, derpNode.HostName), strconv.Itoa(port))
 		conn, err = dialer.DialContext(ctx, "tcp6", addr)
 		if err != nil {
 			st.Errors = append(st.Errors, fmt.Sprintf("Error connecting to node %q @ %q over IPv6: %v", derpNode.HostName, addr, err))
@@ -117,7 +118,7 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 
 			// Upgrade to TLS and verify that works properly.
 			tlsConn := tls.Client(conn, &tls.Config{
-				ServerName: firstNonzero(derpNode.CertName, derpNode.HostName),
+				ServerName: cmp.Or(derpNode.CertName, derpNode.HostName),
 				// TODO(andrew-d): we should print more
 				// detailed failure information on if/why TLS
 				// verification fails
@@ -166,7 +167,7 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 			addr = addrs[0]
 		}
 
-		addrPort := netip.AddrPortFrom(addr, uint16(firstNonzero(derpNode.STUNPort, 3478)))
+		addrPort := netip.AddrPortFrom(addr, uint16(cmp.Or(derpNode.STUNPort, 3478)))
 
 		txID := stun.NewTxID()
 		req := stun.Request(txID)
@@ -292,13 +293,3 @@ func (h *Handler) serveDebugDERPRegion(w http.ResponseWriter, r *http.Request) {
 	//   issued in the first place, tell them specifically that the
 	// 	 cert is bad not just that the connection failed.
 }
-
-func firstNonzero[T comparable](items ...T) T {
-	var zero T
-	for _, item := range items {
-		if item != zero {
-			return item
-		}
-	}
-	return zero
-}

types/lazy/lazy.go

@@ -120,41 +120,6 @@ func (z *SyncValue[T]) PeekErr() (v T, err error, ok bool) {
 	return zero, nil, false
 }
 
-// SyncFunc wraps a function to make it lazy.
-//
-// The returned function calls fill the first time it's called, and returns
-// fill's result on every subsequent call.
-//
-// The returned function is safe for concurrent use.
-func SyncFunc[T any](fill func() T) func() T {
-	var (
-		once sync.Once
-		v    T
-	)
-	return func() T {
-		once.Do(func() { v = fill() })
-		return v
-	}
-}
-
-// SyncFuncErr wraps a function to make it lazy.
-//
-// The returned function calls fill the first time it's called, and returns
-// fill's results on every subsequent call.
-//
-// The returned function is safe for concurrent use.
-func SyncFuncErr[T any](fill func() (T, error)) func() (T, error) {
-	var (
-		once sync.Once
-		v    T
-		err  error
-	)
-	return func() (T, error) {
-		once.Do(func() { v, err = fill() })
-		return v, err
-	}
-}
-
 // TB is a subset of testing.TB that we use to set up test helpers.
 // It's defined here to avoid pulling in the testing package.
 type TB interface {

types/lazy/sync_test.go

@@ -354,46 +354,3 @@ func TestSyncValueSetForTest(t *testing.T) {
 		})
 	}
 }
-
-func TestSyncFunc(t *testing.T) {
-	f := SyncFunc(fortyTwo)
-
-	n := int(testing.AllocsPerRun(1000, func() {
-		got := f()
-		if got != 42 {
-			t.Fatalf("got %v; want 42", got)
-		}
-	}))
-	if n != 0 {
-		t.Errorf("allocs = %v; want 0", n)
-	}
-}
-
-func TestSyncFuncErr(t *testing.T) {
-	f := SyncFuncErr(func() (int, error) {
-		return 42, nil
-	})
-	n := int(testing.AllocsPerRun(1000, func() {
-		got, err := f()
-		if got != 42 || err != nil {
-			t.Fatalf("got %v, %v; want 42, nil", got, err)
-		}
-	}))
-	if n != 0 {
-		t.Errorf("allocs = %v; want 0", n)
-	}
-
-	wantErr := errors.New("test error")
-	f = SyncFuncErr(func() (int, error) {
-		return 0, wantErr
-	})
-	n = int(testing.AllocsPerRun(1000, func() {
-		got, err := f()
-		if got != 0 || err != wantErr {
-			t.Fatalf("got %v, %v; want 0, %v", got, err, wantErr)
-		}
-	}))
-	if n != 0 {
-		t.Errorf("allocs = %v; want 0", n)
-	}
-}

util/uniq/slice.go

@@ -7,11 +7,10 @@ import (
 	"fmt"
 	"runtime"
 	"strings"
-
-	"tailscale.com/types/lazy"
+	"sync"
 )
 
-var stringLazy = lazy.SyncFunc(func() string {
+var stringLazy = sync.OnceValue(func() string {
 	var ret strings.Builder
 	ret.WriteString(Short())
 	ret.WriteByte('\n')

util/uniq/slice_test.go

@@ -9,6 +9,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"sync"
 
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/lazy"
@@ -174,7 +175,7 @@ func IsUnstableBuild() bool {
 	})
 }
 
-var isDev = lazy.SyncFunc(func() bool {
+var isDev = sync.OnceValue(func() bool {
 	return strings.Contains(Short(), "-dev")
 })