all: adopt maps and cmp helpers

cmd/headscale/cli/users.go

@@ -36,9 +36,7 @@ func usernameAndIDFromFlag(cmd *cobra.Command) (uint64, string, error) {
 
 	// Normalise unset/negative identifiers to 0 so the uint64
 	// conversion does not produce a bogus large value.
-	if identifier < 0 {
-		identifier = 0
-	}
+	identifier = max(identifier, 0)
 
 	return uint64(identifier), username, nil //nolint:gosec // identifier is clamped to >= 0 above
 }

hscontrol/mapper/mapper.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/fs"
+	"maps"
 	"net/url"
 	"os"
 	"path"
@@ -70,7 +71,6 @@ func generateUserProfiles(
 	peers views.Slice[types.NodeView],
 ) []tailcfg.UserProfile {
 	userMap := make(map[uint]*types.UserView)
-	ids := make([]uint, 0, len(userMap))
 
 	user := node.Owner()
 	if !user.Valid() {
@@ -81,9 +81,7 @@ func generateUserProfiles(
 		return nil
 	}
 
-	userID := user.Model().ID
-	userMap[userID] = &user
-	ids = append(ids, userID)
+	userMap[user.Model().ID] = &user
 
 	for _, peer := range peers.All() {
 		peerUser := peer.Owner()
@@ -91,20 +89,13 @@ func generateUserProfiles(
 			continue
 		}
 
-		peerUserID := peerUser.Model().ID
-		userMap[peerUserID] = &peerUser
-		ids = append(ids, peerUserID)
+		userMap[peerUser.Model().ID] = &peerUser
 	}
 
-	slices.Sort(ids)
-	ids = slices.Compact(ids)
-
 	var profiles []tailcfg.UserProfile
 
-	for _, id := range ids {
-		if userMap[id] != nil {
-			profiles = append(profiles, userMap[id].TailscaleUserProfile())
-		}
+	for _, id := range slices.Sorted(maps.Keys(userMap)) {
+		profiles = append(profiles, userMap[id].TailscaleUserProfile())
 	}
 
 	return profiles

hscontrol/policy/v2/tailnet_state_caps.go

@@ -13,6 +13,7 @@ package v2
 // one exists.
 
 import (
+	"maps"
 	"slices"
 	"strings"
 
@@ -170,15 +171,10 @@ func stripUnmodelledTailnetStateCaps(cm tailcfg.NodeCapMap) tailcfg.NodeCapMap {
 		return nil
 	}
 
-	out := make(tailcfg.NodeCapMap, len(cm))
-
-	for k, v := range cm {
-		if isUnmodelledTailnetStateCap(k) {
-			continue
-		}
-
-		out[k] = v
-	}
+	out := maps.Clone(cm)
+	maps.DeleteFunc(out, func(k tailcfg.NodeCapability, _ []tailcfg.RawMessage) bool {
+		return isUnmodelledTailnetStateCap(k)
+	})
 
 	if len(out) == 0 {
 		return nil

hscontrol/policy/v2/types.go

@@ -1300,10 +1300,8 @@ func (g *Groups) Contains(group *Group) error {
 		return nil
 	}
 
-	for defined := range map[Group]Usernames(*g) {
-		if defined == *group {
-			return nil
-		}
+	if _, ok := (*g)[*group]; ok {
+		return nil
 	}
 
 	return fmt.Errorf("%w: %q", ErrGroupNotDefined, group)
@@ -1483,10 +1481,8 @@ func (to TagOwners) Contains(tagOwner *Tag) error {
 		return nil
 	}
 
-	for defined := range map[Tag]Owners(to) {
-		if defined == *tagOwner {
-			return nil
-		}
+	if _, ok := to[*tagOwner]; ok {
+		return nil
 	}
 
 	return fmt.Errorf("%w: %q", ErrTagNotDefined, tagOwner)

hscontrol/state/state.go

@@ -208,10 +208,7 @@ func (s *State) lockRegistration(machineKey key.MachinePublic) func() {
 // NewState creates and initializes a new [State] instance, setting up the database,
 // IP allocator, DERP map, policy manager, and loading existing users and nodes.
 func NewState(cfg *types.Config) (*State, error) {
-	cacheExpiration := registerCacheExpiration
-	if cfg.Tuning.RegisterCacheExpiration != 0 {
-		cacheExpiration = cfg.Tuning.RegisterCacheExpiration
-	}
+	cacheExpiration := cmp.Or(cfg.Tuning.RegisterCacheExpiration, registerCacheExpiration)
 
 	cacheMaxEntries := defaultRegisterCacheMaxEntries
 	if cfg.Tuning.RegisterCacheMaxEntries > 0 {
@@ -264,15 +261,9 @@ func NewState(cfg *types.Config) (*State, error) {
 
 	// Apply defaults for [NodeStore] batch configuration if not set.
 	// This ensures tests that create Config directly (without viper) still work.
-	batchSize := cfg.Tuning.NodeStoreBatchSize
-	if batchSize == 0 {
-		batchSize = defaultNodeStoreBatchSize
-	}
+	batchSize := cmp.Or(cfg.Tuning.NodeStoreBatchSize, defaultNodeStoreBatchSize)
 
-	batchTimeout := cfg.Tuning.NodeStoreBatchTimeout
-	if batchTimeout == 0 {
-		batchTimeout = defaultNodeStoreBatchTimeout
-	}
+	batchTimeout := cmp.Or(cfg.Tuning.NodeStoreBatchTimeout, defaultNodeStoreBatchTimeout)
 
 	// [policy.PolicyManager.BuildPeerMap] handles both global and per-node filter complexity.
 	// This moves the complex peer relationship logic into the policy package where it belongs.
@@ -2588,7 +2579,7 @@ func (s *State) HandleNodeFromPreAuthKey(
 			Expiry:                 reqExpiry,
 			RegisterMethod:         util.RegisterMethodAuthKey,
 			PreAuthKey:             pak,
-			ExistingNodeForNetinfo: cmp.Or(differentUserNode, types.NodeView{}),
+			ExistingNodeForNetinfo: differentUserNode,
 		})
 		if err != nil {
 			return types.NodeView{}, change.Change{}, fmt.Errorf("creating new node: %w", err)

integration/scenario.go

@@ -1399,17 +1399,11 @@ func (s *Scenario) GetIPs(user string) ([]netip.Addr, error) {
 
 // GetClients returns all [TailscaleClient]s associated with a [User] in a [Scenario].
 func (s *Scenario) GetClients(user string) ([]TailscaleClient, error) {
-	var clients []TailscaleClient
-
 	if ns, ok := s.users[user]; ok {
-		for _, client := range ns.Clients {
-			clients = append(clients, client)
-		}
-
-		return clients, nil
+		return xmaps.Values(ns.Clients), nil
 	}
 
-	return clients, fmt.Errorf("getting clients: %w", errNoUserAvailable)
+	return nil, fmt.Errorf("getting clients: %w", errNoUserAvailable)
 }
 
 // ListTailscaleClients returns a list of [TailscaleClient]s given the [User]s

tools/capver/main.go

@@ -10,15 +10,14 @@ import (
 	"go/format"
 	"io"
 	"log"
+	"maps"
 	"net/http"
 	"os"
 	"regexp"
 	"slices"
-	"sort"
 	"strconv"
 	"strings"
 
-	xmaps "golang.org/x/exp/maps"
 	"tailscale.com/tailcfg"
 )
 
@@ -246,8 +245,7 @@ func getCapabilityVersions(ctx context.Context) (map[string]tailcfg.CapabilityVe
 
 func calculateMinSupportedCapabilityVersion(versions map[string]tailcfg.CapabilityVersion) tailcfg.CapabilityVersion {
 	// Since we now store minor versions directly, just sort and take the oldest of the latest N
-	minorVersions := xmaps.Keys(versions)
-	sort.Strings(minorVersions)
+	minorVersions := slices.Sorted(maps.Keys(versions))
 
 	supportedCount := min(len(minorVersions), supportedMajorMinorVersions)
 
@@ -264,8 +262,7 @@ func calculateMinSupportedCapabilityVersion(versions map[string]tailcfg.Capabili
 // firstTailscaleVerPerCapVer inverts versions into a map from each capability
 // version to the first (lowest-sorted) Tailscale minor version reporting it.
 func firstTailscaleVerPerCapVer(versions map[string]tailcfg.CapabilityVersion) map[tailcfg.CapabilityVersion]string {
-	sortedVersions := xmaps.Keys(versions)
-	sort.Strings(sortedVersions)
+	sortedVersions := slices.Sorted(maps.Keys(versions))
 
 	capVerToTailscaleVer := make(map[tailcfg.CapabilityVersion]string)
 
@@ -288,8 +285,7 @@ func writeCapabilityVersionsToFile(versions map[string]tailcfg.CapabilityVersion
 	content.WriteString("\n\n")
 	content.WriteString("var tailscaleToCapVer = map[string]tailcfg.CapabilityVersion{\n")
 
-	sortedVersions := xmaps.Keys(versions)
-	sort.Strings(sortedVersions)
+	sortedVersions := slices.Sorted(maps.Keys(versions))
 
 	for _, version := range sortedVersions {
 		fmt.Fprintf(&content, "\t\"%s\": %d,\n", version, versions[version])
@@ -302,8 +298,7 @@ func writeCapabilityVersionsToFile(versions map[string]tailcfg.CapabilityVersion
 
 	capVerToTailscaleVer := firstTailscaleVerPerCapVer(versions)
 
-	capsSorted := xmaps.Keys(capVerToTailscaleVer)
-	slices.Sort(capsSorted)
+	capsSorted := slices.Sorted(maps.Keys(capVerToTailscaleVer))
 
 	for _, capVer := range capsSorted {
 		fmt.Fprintf(&content, "\t%d:\t\t\"%s\",\n", capVer, capVerToTailscaleVer[capVer])
@@ -337,8 +332,7 @@ func writeCapabilityVersionsToFile(versions map[string]tailcfg.CapabilityVersion
 
 func writeTestDataFile(versions map[string]tailcfg.CapabilityVersion, minSupportedCapVer tailcfg.CapabilityVersion) error {
 	// Sort minor versions
-	minorVersions := xmaps.Keys(versions)
-	sort.Strings(minorVersions)
+	minorVersions := slices.Sorted(maps.Keys(versions))
 
 	// Take latest N
 	supportedCount := min(len(minorVersions), supportedMajorMinorVersions)
@@ -416,8 +410,7 @@ func writeTestDataFile(versions map[string]tailcfg.CapabilityVersion, minSupport
 	fmt.Fprintf(&content, "\t{%d, \"%s\"},\n", minSupportedCapVer, minVersionString)
 
 	// Add a few more test cases
-	capsSorted := xmaps.Keys(capVerToTailscaleVer)
-	slices.Sort(capsSorted)
+	capsSorted := slices.Sorted(maps.Keys(capVerToTailscaleVer))
 
 	testCount := 0
 	for _, capVer := range capsSorted {