chore: upgrade to Go 1.26 and modernize

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
-          go-version: "1.25.x"
+          go-version: "1.26.x"
       - run: go test ./...
       - run: go test ./...
         env:

README.md

@@ -51,7 +51,7 @@ and Lip Gloss.
 
 ## Install
 
-`teleop` currently requires Go 1.25 or newer.
+`teleop` currently requires Go 1.26 or newer.
 
 ```sh
 go get github.com/open-ships/teleop

action/action.go

@@ -5,7 +5,7 @@ package action
 import (
 	"context"
 	"fmt"
-	"sort"
+	"slices"
 	"sync"
 	"sync/atomic"
 
@@ -45,7 +45,7 @@ func (Event) Kind() teleop.EventKind { return EventKind }
 // CloneEvent implements teleop.EventCloner.
 func (e Event) CloneEvent() teleop.Event {
 	e.Meta = e.Meta.Clone()
-	e.Controls = append([]teleop.ControlID(nil), e.Controls...)
+	e.Controls = slices.Clone(e.Controls)
 	if e.Value.Vector != nil {
 		vector := *e.Value.Vector
 		e.Value.Vector = &vector
@@ -148,7 +148,7 @@ type Mapper struct {
 // New validates and copies bindings. Invalid bindings panic instead of silently
 // matching a different control.
 func New(bindings ...Binding) *Mapper {
-	copied := append([]Binding(nil), bindings...)
+	copied := slices.Clone(bindings)
 	for index := range copied {
 		copied[index].Controls = canonicalControls(copied[index].Controls)
 		if err := validateBinding(copied[index]); err != nil {
@@ -203,11 +203,7 @@ func validateBinding(binding Binding) error {
 // Process implements teleop.Processor.
 func (m *Mapper) Process(input teleop.Event) []teleop.Event {
 	mapped := m.Map(input)
-	result := make([]teleop.Event, len(mapped))
-	for index := range mapped {
-		result[index] = mapped[index]
-	}
-	return result
+	return asEvents(mapped)
 }
 
 // ProcessContext implements teleop.ContextProcessor.
@@ -217,11 +213,7 @@ func (m *Mapper) ProcessContext(
 	input teleop.Event,
 ) ([]teleop.Event, error) {
 	mapped := m.mapInput(input, processing)
-	result := make([]teleop.Event, len(mapped))
-	for index := range mapped {
-		result[index] = mapped[index]
-	}
-	return result, nil
+	return asEvents(mapped), nil
 }
 
 // Map returns strongly typed application actions using an instance-unique
@@ -285,7 +277,7 @@ func (m *Mapper) mapInput(
 			Action:   binding.Action,
 			Phase:    values.phase,
 			Control:  values.control,
-			Controls: append([]teleop.ControlID(nil), values.controls...),
+			Controls: slices.Clone(values.controls),
 			Value:    values.value,
 		})
 	}
@@ -387,28 +379,20 @@ func triggerControl(trigger teleop.TriggerID) (teleop.ControlID, bool) {
 	}
 }
 
-func canonicalControls(values []teleop.ControlID) []teleop.ControlID {
-	result := append([]teleop.ControlID(nil), values...)
-	sort.Slice(result, func(i, j int) bool { return result[i] < result[j] })
-	write := 0
-	for _, value := range result {
-		if value == "" || write > 0 && result[write-1] == value {
-			continue
-		}
-		result[write] = value
-		write++
+// asEvents widens mapped actions to the open teleop.Event interface.
+func asEvents[T teleop.Event](values []T) []teleop.Event {
+	result := make([]teleop.Event, len(values))
+	for index, value := range values {
+		result[index] = value
 	}
-	return result[:write]
+	return result
+}
+
+func canonicalControls(values []teleop.ControlID) []teleop.ControlID {
+	sorted := slices.Compact(slices.Sorted(slices.Values(values)))
+	return slices.DeleteFunc(sorted, func(value teleop.ControlID) bool { return value == "" })
 }
 
 func equalControls(left, right []teleop.ControlID) bool {
-	if len(left) != len(right) {
-		return false
-	}
-	for index := range left {
-		if left[index] != right[index] {
-			return false
-		}
-	}
-	return true
+	return slices.Equal(left, right)
 }

audit/integrity_test.go

@@ -863,7 +863,7 @@ func TestManifestBindsSession(t *testing.T) {
 func splitLines(t *testing.T, raw []byte) [][]byte {
 	t.Helper()
 	var lines [][]byte
-	for _, line := range strings.Split(strings.TrimRight(string(raw), "\n"), "\n") {
+	for line := range strings.SplitSeq(strings.TrimRight(string(raw), "\n"), "\n") {
 		lines = append(lines, []byte(line))
 	}
 	return lines

audit/provenance.go

@@ -1,6 +1,7 @@
 package audit
 
 import (
+	"maps"
 	"os"
 	"runtime"
 	"runtime/debug"
@@ -88,19 +89,7 @@ func CaptureProvenance() Provenance {
 // Clone returns a deep copy so a recorder cannot observe later mutation of a
 // caller's maps.
 func (p Provenance) Clone() Provenance {
-	if p.Config != nil {
-		config := make(map[string]any, len(p.Config))
-		for key, value := range p.Config {
-			config[key] = value
-		}
-		p.Config = config
-	}
-	if p.Platform != nil {
-		platform := make(map[string]string, len(p.Platform))
-		for key, value := range p.Platform {
-			platform[key] = value
-		}
-		p.Platform = platform
-	}
+	p.Config = maps.Clone(p.Config)
+	p.Platform = maps.Clone(p.Platform)
 	return p
 }

clock.go

@@ -65,10 +65,7 @@ func (m *clockMonitor) observe(now time.Time) clockSample {
 	wallDelta := now.Round(0).Sub(m.lastWall.Round(0))
 	monoDelta := monotonic - m.lastMono
 	divergence := wallDelta - monoDelta
-	magnitude := divergence
-	if magnitude < 0 {
-		magnitude = -magnitude
-	}
+	magnitude := divergence.Abs()
 	if magnitude >= m.threshold {
 		m.steps++
 		sample.Step = divergence

cmd/teleop-monitor/tui.go

@@ -922,10 +922,7 @@ func keyHint(key, action string) string {
 }
 
 func padBetween(left, right string, width int) string {
-	spaces := width - lipgloss.Width(left) - lipgloss.Width(right)
-	if spaces < 1 {
-		spaces = 1
-	}
+	spaces := max(width-lipgloss.Width(left)-lipgloss.Width(right), 1)
 	return left + strings.Repeat(" ", spaces) + right
 }
 

cmd/teleop-monitor/tui_test.go

@@ -354,7 +354,7 @@ func TestMonitorModelTogglesRumble(t *testing.T) {
 	if repeated != nil {
 		t.Fatal("repeated rumble key started a second request")
 	}
-	for _, line := range strings.Split(model.renderHaptics(30), "\n") {
+	for line := range strings.SplitSeq(model.renderHaptics(30), "\n") {
 		if lipgloss.Width(line) > 30 {
 			t.Fatalf(
 				"compact haptic line is %d cells wide, want at most 30",
@@ -523,7 +523,7 @@ func TestMonitorModelAlternatesRumbleAtConfiguredInterval(t *testing.T) {
 			t.Fatalf("alternating haptic controls do not contain %q", expected)
 		}
 	}
-	for _, line := range strings.Split(model.renderHaptics(30), "\n") {
+	for line := range strings.SplitSeq(model.renderHaptics(30), "\n") {
 		if lipgloss.Width(line) > 30 {
 			t.Fatalf(
 				"compact alternating haptic line is %d cells wide, want at most 30",
@@ -756,7 +756,7 @@ func TestMonitorModelReportsUnavailableAndFailedRumble(t *testing.T) {
 			t.Fatalf("failed rumble view does not contain %q", expected)
 		}
 	}
-	for _, line := range strings.Split(model.renderHaptics(30), "\n") {
+	for line := range strings.SplitSeq(model.renderHaptics(30), "\n") {
 		if lipgloss.Width(line) > 30 {
 			t.Fatalf(
 				"compact haptic error line is %d cells wide, want at most 30",

command.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"slices"
 	"time"
 )
 
@@ -69,7 +70,7 @@ func (c *Controller) RecordCommand(ctx context.Context, command Command) error {
 		payload:  payload,
 		issuedAt: c.clock.Now(),
 	}
-	request.command.Causes = append([]EventID(nil), command.Causes...)
+	request.command.Causes = slices.Clone(command.Causes)
 	request.command.Payload = nil
 
 	// A caller may use a deferred controller solely for audit-backed command

control.go

@@ -1,5 +1,7 @@
 package teleop
 
+import "slices"
+
 // ControllerType identifies a family of game controllers. It is string-backed
 // so third-party providers can add controller types without changing teleop.
 type ControllerType string
@@ -89,7 +91,7 @@ var standardButtons = []ControlID{
 
 // StandardButtonIDs returns the standard physical buttons in a stable order.
 func StandardButtonIDs() []ControlID {
-	return append([]ControlID(nil), standardButtons...)
+	return slices.Clone(standardButtons)
 }
 
 // StickID selects one of the two standard analog sticks.

controller.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"math"
+	"slices"
 	"sync"
 	"time"
 )
@@ -522,10 +523,7 @@ func (c *Controller) onTick(now time.Time) error {
 	if meta.ReceivedAt.IsZero() {
 		meta.ReceivedAt = c.startedAt
 	}
-	age := now.Sub(meta.ReceivedAt)
-	if age < 0 {
-		age = 0
-	}
+	age := max(now.Sub(meta.ReceivedAt), 0)
 	stale := c.options.staleAfter > 0 && age >= c.options.staleAfter
 	if stale && !meta.Stale && c.options.neutralizeOnStale {
 		if err := c.neutralize(now, "input stale"); err != nil {
@@ -755,7 +753,7 @@ func (c *Controller) nextHeaderAt(
 		Monotonic:         c.clocks.since(publishedAt),
 		ReceivedMonotonic: c.clocks.since(receivedAt),
 		DeviceTimestamp:   deviceTimestamp,
-		Causes:            append([]EventID(nil), causes...),
+		Causes:            slices.Clone(causes),
 		Synthetic:         synthetic,
 	}
 }
@@ -826,7 +824,7 @@ func (c *Controller) publishTerminal(event Event) {
 		if c.processorDisabled[index] {
 			continue
 		}
-		stageInputs := append([]Event(nil), visible...)
+		stageInputs := slices.Clone(visible)
 		var derived []Event
 		failed := false
 		for _, input := range stageInputs {
@@ -865,13 +863,13 @@ func (c *Controller) dispatchTerminal(event Event) (completed bool) {
 }
 
 func (c *Controller) processStages(inputs []Event, start int) error {
-	visible := append([]Event(nil), inputs...)
+	visible := slices.Clone(inputs)
 	for index := start; index < len(c.options.processors); index++ {
 		if c.processorDisabled[index] {
 			continue
 		}
 		processor := c.options.processors[index]
-		stageInputs := append([]Event(nil), visible...)
+		stageInputs := slices.Clone(visible)
 		derived := make([]Event, 0, len(stageInputs))
 		for _, input := range stageInputs {
 			output, err := c.callProcessor(processor, input)

controller_remediation_test.go

@@ -240,29 +240,29 @@ func TestSubscriptionCloseBroadcastsToAllBlockedReaders(t *testing.T) {
 	}
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
-	for index := 0; index < 2; index++ {
+	for range 2 {
 		if _, err := subscription.Next(ctx); err != nil {
 			t.Fatal(err)
 		}
 	}
 
 	started := make(chan struct{}, 4)
 	finished := make(chan error, 4)
-	for index := 0; index < 4; index++ {
+	for range 4 {
 		go func() {
 			started <- struct{}{}
 			_, err := subscription.Next(context.Background())
 			finished <- err
 		}()
 	}
-	for index := 0; index < 4; index++ {
+	for range 4 {
 		<-started
 	}
 	time.Sleep(10 * time.Millisecond)
 	if err := subscription.Close(); err != nil {
 		t.Fatal(err)
 	}
-	for index := 0; index < 4; index++ {
+	for index := range 4 {
 		select {
 		case err := <-finished:
 			if !errors.Is(err, teleop.ErrClosed) {
@@ -642,7 +642,7 @@ func TestSlowSinkDoesNotDelayCanonicalSnapshot(t *testing.T) {
 	waitForSnapshot(t, controller, func(_ teleop.State, meta teleop.StateMeta) bool {
 		return meta.Connected
 	})
-	for index := 0; index < 8; index++ {
+	for index := range 8 {
 		if err := source.Push(context.Background(), teleop.State{
 			LeftTrigger: float32(index) / 7,
 		}); err != nil {

device.go

@@ -2,6 +2,8 @@ package teleop
 
 import (
 	"context"
+	"maps"
+	"slices"
 	"time"
 )
 
@@ -69,18 +71,15 @@ func (c Capabilities) Clone() Capabilities {
 	if !c.AuditGrade.Valid() {
 		c.AuditGrade = AuditUnavailable
 	}
-	c.Controls = append([]ControlDescriptor(nil), c.Controls...)
+	c.Controls = slices.Clone(c.Controls)
 	return c
 }
 
 // Supports reports whether id appears in the discovered control list.
 func (c Capabilities) Supports(id ControlID) bool {
-	for _, control := range c.Controls {
-		if control.ID == id {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(c.Controls, func(control ControlDescriptor) bool {
+		return control.ID == id
+	})
 }
 
 // Descriptor contains the stable metadata and capabilities of one discovered
@@ -100,12 +99,7 @@ type Descriptor struct {
 // Clone returns an isolated copy of the device descriptor.
 func (d Descriptor) Clone() Descriptor {
 	d.Capability = d.Capability.Clone()
-	if d.Properties != nil {
-		d.Properties = make(map[string]string, len(d.Properties))
-		for key, value := range d.Properties {
-			d.Properties[key] = value
-		}
-	}
+	d.Properties = maps.Clone(d.Properties)
 	return d
 }