util/slicesx: add MapKeys and MapValues from golang.org/x/exp/maps

Importing the ~deprecated golang.org/x/exp/maps as "xmaps" to not
shadow the std "maps" was getting ugly.

And using slices.Collect on an iterator is verbose & allocates more.

So copy (x)maps.Keys+Values into our slicesx package instead.

Updates #cleanup
Updates #12912
Updates #14514 (pulled out of that change)

Change-Id: I5e68d12729934de93cf4a9cd87c367645f86123a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/systray/systray.go

@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"io"
 	"log"
-	"maps"
 	"net/http"
 	"os"
 	"os/signal"
@@ -31,6 +30,7 @@ import (
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
+	"tailscale.com/util/slicesx"
 	"tailscale.com/util/stringsx"
 )
 
@@ -616,7 +616,7 @@ type mullvadPeers struct {
 
 // sortedCountries returns countries containing mullvad nodes, sorted by name.
 func (mp mullvadPeers) sortedCountries() []*mvCountry {
-	countries := slices.Collect(maps.Values(mp.countries))
+	countries := slicesx.MapValues(mp.countries)
 	slices.SortFunc(countries, func(a, b *mvCountry) int {
 		return stringsx.CompareFold(a.name, b.name)
 	})
@@ -632,7 +632,7 @@ type mvCountry struct {
 
 // sortedCities returns cities containing mullvad nodes, sorted by name.
 func (mc *mvCountry) sortedCities() []*mvCity {
-	cities := slices.Collect(maps.Values(mc.cities))
+	cities := slicesx.MapValues(mc.cities)
 	slices.SortFunc(cities, func(a, b *mvCity) int {
 		return stringsx.CompareFold(a.name, b.name)
 	})

cmd/tailscale/cli/exitnode.go

@@ -15,10 +15,10 @@ import (
 
 	"github.com/kballard/go-shellquote"
 	"github.com/peterbourgon/ff/v3/ffcli"
-	xmaps "golang.org/x/exp/maps"
 	"tailscale.com/envknob"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
+	"tailscale.com/util/slicesx"
 )
 
 func exitNodeCmd() *ffcli.Command {
@@ -255,7 +255,7 @@ func filterFormatAndSortExitNodes(peers []*ipnstate.PeerStatus, filterBy string)
 	}
 
 	filteredExitNodes := filteredExitNodes{
-		Countries: xmaps.Values(countries),
+		Countries: slicesx.MapValues(countries),
 	}
 
 	for _, country := range filteredExitNodes.Countries {

cmd/tailscale/cli/serve_legacy.go

@@ -27,6 +27,7 @@ import (
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
+	"tailscale.com/util/slicesx"
 	"tailscale.com/version"
 )
 
@@ -707,10 +708,7 @@ func (e *serveEnv) printWebStatusTree(sc *ipn.ServeConfig, hp ipn.HostPort) erro
 		return "", ""
 	}
 
-	var mounts []string
-	for k := range sc.Web[hp].Handlers {
-		mounts = append(mounts, k)
-	}
+	mounts := slicesx.MapKeys(sc.Web[hp].Handlers)
 	sort.Slice(mounts, func(i, j int) bool {
 		return len(mounts[i]) < len(mounts[j])
 	})

cmd/tailscale/cli/serve_v2.go

@@ -28,6 +28,7 @@ import (
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
 	"tailscale.com/util/mak"
+	"tailscale.com/util/slicesx"
 	"tailscale.com/version"
 )
 
@@ -439,11 +440,7 @@ func (e *serveEnv) messageForPort(sc *ipn.ServeConfig, st *ipnstate.Status, dnsN
 	}
 
 	if sc.Web[hp] != nil {
-		var mounts []string
-
-		for k := range sc.Web[hp].Handlers {
-			mounts = append(mounts, k)
-		}
+		mounts := slicesx.MapKeys(sc.Web[hp].Handlers)
 		sort.Slice(mounts, func(i, j int) bool {
 			return len(mounts[i]) < len(mounts[j])
 		})

cmd/tailscale/depaware.txt

@@ -202,7 +202,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
         golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
    W    golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+
-        golang.org/x/exp/maps                                        from tailscale.com/cmd/tailscale/cli+
+        golang.org/x/exp/maps                                        from tailscale.com/util/syspolicy/internal/metrics+
         golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http+

cmd/tailscaled/depaware.txt

@@ -449,7 +449,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/crypto/sha3                                     from crypto/internal/mlkem768+
   LD    golang.org/x/crypto/ssh                                      from github.com/pkg/sftp+
         golang.org/x/exp/constraints                                 from github.com/dblohm7/wingoes/pe+
-        golang.org/x/exp/maps                                        from tailscale.com/appc+
+        golang.org/x/exp/maps                                        from tailscale.com/ipn/store/mem+
         golang.org/x/net/bpf                                         from github.com/mdlayher/genetlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from golang.org/x/net/http2+

cmd/testwrapper/testwrapper.go

@@ -29,8 +29,8 @@ import (
 	"github.com/dave/courtney/tester"
 	"github.com/dave/patsy"
 	"github.com/dave/patsy/vos"
-	xmaps "golang.org/x/exp/maps"
 	"tailscale.com/cmd/testwrapper/flakytest"
+	"tailscale.com/util/slicesx"
 )
 
 const (
@@ -350,7 +350,7 @@ func main() {
 		if len(toRetry) == 0 {
 			continue
 		}
-		pkgs := xmaps.Keys(toRetry)
+		pkgs := slicesx.MapKeys(toRetry)
 		sort.Strings(pkgs)
 		nextRun := &nextRun{
 			attempt: thisRun.attempt + 1,