merge: integrate proxyctl ticket 06

cmd/proxyctl/main.go

@@ -9,6 +9,7 @@ import (
 	tea "github.com/charmbracelet/bubbletea"
 
 	"proxyctl/internal/app"
+	"proxyctl/internal/dockerdaemon"
 	"proxyctl/internal/profile"
 	"proxyctl/internal/shell"
 	"proxyctl/internal/target"
@@ -23,11 +24,17 @@ func main() {
 }
 
 func run(args []string, input io.Reader, output io.Writer) error {
+	return runWithSystemTargets(args, input, output, nil)
+}
+
+// runWithSystemTargets keeps process smoke tests hermetic. A nil slice selects
+// production system Targets; a non-nil slice supplies fakes (or no Targets).
+func runWithSystemTargets(args []string, input io.Reader, output io.Writer, systemTargets []target.Target) error {
 	executable, err := os.Executable()
 	if err != nil {
 		return fmt.Errorf("locate proxyctl executable: %w", err)
 	}
-	return runWithEnvironment(args, input, output, processEnvironment{}, nil, executable)
+	return runWithEnvironmentAndTargets(args, input, output, processEnvironment{}, nil, executable, systemTargets)
 }
 
 type processEnvironment struct{}
@@ -41,6 +48,10 @@ func (processEnvironment) LookupUser(name string) (profile.UserIdentity, error)
 func (processEnvironment) LookupEnv(name string) (string, bool) { return os.LookupEnv(name) }
 
 func runWithEnvironment(args []string, input io.Reader, output io.Writer, environment profile.IdentityEnvironment, files shell.FileSystem, executable string) error {
+	return runWithEnvironmentAndTargets(args, input, output, environment, files, executable, nil)
+}
+
+func runWithEnvironmentAndTargets(args []string, input io.Reader, output io.Writer, environment profile.IdentityEnvironment, files shell.FileSystem, executable string, systemTargets []target.Target) error {
 	profileConfiguration, err := profile.ResolveConfiguration(environment)
 	if err != nil {
 		return err
@@ -74,7 +85,11 @@ func runWithEnvironment(args []string, input io.Reader, output io.Writer, enviro
 	}
 
 	store := profile.NewOwnedFileStoreAt(profileConfiguration.Path, profileConfiguration.Owner, profileConfiguration.TrustedRoot)
-	application, err := app.NewWithTargets(store, []target.Target{shellTarget})
+	if systemTargets == nil {
+		systemTargets = []target.Target{dockerdaemon.New(dockerdaemon.DefaultConfiguration(), nil, nil)}
+	}
+	targets := append([]target.Target{shellTarget}, systemTargets...)
+	application, err := app.NewWithTargets(store, targets)
 	if err != nil {
 		return err
 	}

cmd/proxyctl/main_test.go

@@ -6,12 +6,14 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+
+	"proxyctl/internal/target"
 )
 
 func TestDefaultInvocationStartsTUIWithNoProfileState(t *testing.T) {
 	t.Setenv("XDG_CONFIG_HOME", t.TempDir())
 	var output bytes.Buffer
-	if err := run(nil, strings.NewReader("q"), &output); err != nil {
+	if err := runWithSystemTargets(nil, strings.NewReader("q"), &output, []target.Target{}); err != nil {
 		t.Fatalf("run proxyctl: %v", err)
 	}
 	if !strings.Contains(output.String(), "No Active Profile") {
@@ -27,7 +29,7 @@ func TestDefaultInvocationLoadsPersistedActiveProfile(t *testing.T) {
   "activeProfile": "office"
 }`)
 	var output bytes.Buffer
-	if err := run(nil, strings.NewReader("q"), &output); err != nil {
+	if err := runWithSystemTargets(nil, strings.NewReader("q"), &output, []target.Target{}); err != nil {
 		t.Fatalf("run proxyctl: %v", err)
 	}
 	if !strings.Contains(output.String(), "Active Profile: office") {

internal/app/app.go

@@ -44,9 +44,10 @@ type Snapshot struct {
 }
 
 type Result struct {
-	Snapshot Snapshot
-	Notice   string
-	Err      error
+	Snapshot     Snapshot
+	Notice       string
+	Confirmation string
+	Err          error
 }
 
 type Module interface {
@@ -159,6 +160,9 @@ func (a *Application) setTargetDesired(intent Intent) Result {
 	if intent.Enabled && active == nil {
 		return Result{Snapshot: a.Snapshot(), Err: errors.New("no Active Profile; open Profile management before enabling a Target")}
 	}
+	if warning := selected.Confirmation(intent.Enabled); warning != "" && !intent.Confirm {
+		return Result{Snapshot: a.Snapshot(), Confirmation: warning}
+	}
 	result := selected.SetDesired(context.Background(), intent.Enabled, active)
 	a.inspections[selected.ID()] = result.Inspection
 	notice := ""

internal/app/target_test.go

@@ -13,10 +13,11 @@ import (
 )
 
 type fakeTarget struct {
-	available bool
-	state     target.State
-	setErr    error
-	calls     []bool
+	available    bool
+	state        target.State
+	setErr       error
+	confirmation string
+	calls        []bool
 }
 
 func (f *fakeTarget) ID() string { return "shell" }
@@ -29,6 +30,7 @@ func (f *fakeTarget) Availability(context.Context) target.Availability {
 func (f *fakeTarget) Inspect(context.Context, *profile.Profile) target.Inspection {
 	return target.Inspection{State: f.state, Evidence: "actual state"}
 }
+func (f *fakeTarget) Confirmation(bool) string { return f.confirmation }
 func (f *fakeTarget) SetDesired(_ context.Context, enabled bool, _ *profile.Profile) target.OperationResult {
 	f.calls = append(f.calls, enabled)
 	if f.setErr == nil {
@@ -71,6 +73,31 @@ func TestApplicationTargetSeamRequiresActiveProfileAndReturnsTruthfulResults(t *
 	}
 }
 
+func TestApplicationRequiresTargetConfirmationBeforeMutation(t *testing.T) {
+	adapter := &fakeTarget{available: true, state: target.Disabled, confirmation: "Docker will restart immediately and may disrupt running work."}
+	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{targetWithID{fakeTarget: adapter, id: "docker-daemon"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	createAndActivate(t, application)
+
+	warning := application.Dispatch(app.Intent{Kind: app.SetTargetDesired, TargetID: "docker-daemon", Enabled: true})
+	if warning.Confirmation == "" || warning.Err != nil || len(adapter.calls) != 0 || warning.Snapshot.Targets[0].State != target.Disabled {
+		t.Fatalf("unconfirmed result = %#v, calls=%v", warning, adapter.calls)
+	}
+	confirmed := application.Dispatch(app.Intent{Kind: app.SetTargetDesired, TargetID: "docker-daemon", Enabled: true, Confirm: true})
+	if confirmed.Err != nil || len(adapter.calls) != 1 || confirmed.Snapshot.Targets[0].State != target.Enabled {
+		t.Fatalf("confirmed result = %#v, calls=%v", confirmed, adapter.calls)
+	}
+}
+
+type targetWithID struct {
+	*fakeTarget
+	id string
+}
+
+func (t targetWithID) ID() string { return t.id }
+
 func TestApplicationHidesUnavailableTargetButKeepsExplanation(t *testing.T) {
 	adapter := &fakeTarget{available: false, state: target.Disabled}
 	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})

internal/dockerdaemon/dockerdaemon.go

@@ -0,0 +1,434 @@
+// Package dockerdaemon implements the systemd-managed Docker daemon Target.
+package dockerdaemon
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"net/url"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"proxyctl/internal/profile"
+	"proxyctl/internal/securefs"
+	"proxyctl/internal/target"
+)
+
+const service = "docker.service"
+
+type Configuration struct {
+	DaemonConfigPath string
+	RecoveryPath     string
+	TrustedRoot      string
+}
+
+func DefaultConfiguration() Configuration {
+	return Configuration{DaemonConfigPath: "/etc/docker/daemon.json", RecoveryPath: "/var/lib/proxyctl/docker-daemon.json", TrustedRoot: "/"}
+}
+
+type FileSystem interface {
+	ReadFile(string) ([]byte, error)
+	FileMode(string) (os.FileMode, error)
+	AtomicWrite(string, []byte, os.FileMode) error
+	Remove(string) error
+}
+
+type OSFileSystem struct{ store securefs.Store }
+
+func NewOSFileSystem(configuration Configuration) OSFileSystem {
+	root := configuration.TrustedRoot
+	if root == "" {
+		root = "/"
+	}
+	return OSFileSystem{store: securefs.Store{TrustedRoot: root}}
+}
+func (f OSFileSystem) ReadFile(path string) ([]byte, error)      { return f.store.ReadFile(path) }
+func (f OSFileSystem) FileMode(path string) (os.FileMode, error) { return f.store.FileMode(path) }
+func (f OSFileSystem) AtomicWrite(path string, data []byte, mode os.FileMode) error {
+	return f.store.AtomicWrite(path, data, mode)
+}
+func (f OSFileSystem) Remove(path string) error { return f.store.Remove(path) }
+
+type CommandRunner interface {
+	Run(context.Context, string, ...string) ([]byte, error)
+}
+type ExecRunner struct{}
+
+func (ExecRunner) Run(ctx context.Context, name string, args ...string) ([]byte, error) {
+	output, err := exec.CommandContext(ctx, name, args...).CombinedOutput()
+	if err != nil {
+		return output, fmt.Errorf("%s: %s: %w", name, strings.TrimSpace(string(output)), err)
+	}
+	return output, nil
+}
+
+type Adapter struct {
+	configuration Configuration
+	files         FileSystem
+	runner        CommandRunner
+}
+
+func New(configuration Configuration, files FileSystem, runner CommandRunner) *Adapter {
+	if configuration.DaemonConfigPath == "" {
+		configuration.DaemonConfigPath = "/etc/docker/daemon.json"
+	}
+	if configuration.RecoveryPath == "" {
+		configuration.RecoveryPath = "/var/lib/proxyctl/docker-daemon.json"
+	}
+	if files == nil {
+		value := NewOSFileSystem(configuration)
+		files = value
+	}
+	if runner == nil {
+		runner = ExecRunner{}
+	}
+	return &Adapter{configuration: configuration, files: files, runner: runner}
+}
+
+func (a *Adapter) ID() string { return "docker-daemon" }
+func (a *Adapter) Description() target.Description {
+	return target.Description{
+		Name:    "Docker daemon",
+		Summary: "Configures proxying for Docker daemon operations such as registry access, not container network traffic or container/build defaults.",
+		Details: "Uses managed Docker daemon configuration. Every change reloads systemd and immediately restarts Docker, which may disrupt running work. System-file and service permissions are required; proxyctl reports permission errors and never initiates privilege escalation.",
+	}
+}
+func (a *Adapter) Confirmation(bool) string {
+	return "Docker will restart immediately. This may disrupt running containers and other work. Confirm before proxyctl changes daemon configuration."
+}
+func (a *Adapter) Availability(ctx context.Context) target.Availability {
+	availability, _ := a.detect(ctx)
+	return availability
+}
+func (a *Adapter) detect(ctx context.Context) (target.Availability, error) {
+	output, err := a.runner.Run(ctx, "systemctl", "show", service, "--property=LoadState", "--property=FragmentPath")
+	if err != nil {
+		return target.Availability{Evidence: "A supported systemd-managed Docker daemon was not detected"}, err
+	}
+	values := parseProperties(string(output))
+	if values["LoadState"] != "loaded" || strings.TrimSpace(values["FragmentPath"]) == "" {
+		return target.Availability{Evidence: "A supported systemd-managed Docker daemon was not detected"}, nil
+	}
+	return target.Availability{Available: true, Evidence: "Docker daemon service is loaded and managed by systemd at " + values["FragmentPath"]}, nil
+}
+
+func parseProperties(output string) map[string]string {
+	result := map[string]string{}
+	for _, line := range strings.Split(output, "\n") {
+		key, value, ok := strings.Cut(line, "=")
+		if ok {
+			result[strings.TrimSpace(key)] = strings.TrimSpace(value)
+		}
+	}
+	return result
+}
+
+type recovery struct {
+	Original             []byte `json:"original,omitempty"`
+	OriginalExists       bool   `json:"originalExists"`
+	OriginalMode         uint32 `json:"originalMode,omitempty"`
+	ConfigFingerprint    string `json:"configFingerprint"`
+	RestartedFingerprint string `json:"restartedFingerprint,omitempty"`
+}
+
+func (a *Adapter) Inspect(_ context.Context, active *profile.Profile) target.Inspection {
+	metadata, managed, metadataErr := a.readRecovery()
+	data, configErr := a.files.ReadFile(a.configuration.DaemonConfigPath)
+	if managed || (metadataErr != nil && !errors.Is(metadataErr, fs.ErrNotExist)) {
+		if metadataErr != nil {
+			return target.Inspection{State: target.Drifted, Evidence: "managed Docker daemon recovery metadata cannot be read"}
+		}
+		if configErr != nil {
+			return target.Inspection{State: target.Drifted, Evidence: "managed Docker daemon configuration is missing or unreadable"}
+		}
+		if fingerprint(data) == metadata.ConfigFingerprint && active != nil {
+			normalized, err := compatible(*active)
+			if err == nil && configMatchesProfile(data, normalized) {
+				return target.Inspection{State: target.Enabled, Evidence: "managed Docker daemon configuration matches the Active Profile"}
+			}
+		}
+		return target.Inspection{State: target.Drifted, Evidence: "managed Docker daemon configuration does not match the Active Profile"}
+	}
+	if configErr == nil && recognizesProxy(data) {
+		return target.Inspection{State: target.External, Evidence: "recognized proxy settings exist in Docker daemon configuration"}
+	}
+	return target.Inspection{State: target.Disabled, Evidence: "no recognized Docker daemon proxy configuration detected"}
+}
+
+func (a *Adapter) SetDesired(ctx context.Context, enabled bool, active *profile.Profile) target.OperationResult {
+	if enabled && active == nil {
+		return target.OperationResult{Inspection: a.Inspect(ctx, active), Err: errors.New("no Active Profile; open Profile management to create and activate one")}
+	}
+	var normalized profile.Profile
+	var err error
+	if enabled {
+		normalized, err = compatible(*active)
+		if err != nil {
+			return target.OperationResult{Inspection: a.Inspect(ctx, active), Err: redact(err, active)}
+		}
+	}
+	availability, detectionErr := a.detect(ctx)
+	if detectionErr != nil {
+		return target.OperationResult{Inspection: a.Inspect(ctx, active), Err: redact(fmt.Errorf("detect systemd-managed Docker daemon: %w", detectionErr), active)}
+	}
+	if !availability.Available {
+		return target.OperationResult{Inspection: a.Inspect(ctx, active), Err: errors.New("Docker daemon Target is unavailable: a supported systemd-managed Docker daemon was not detected")}
+	}
+	if enabled {
+		err = a.enable(ctx, normalized)
+	} else {
+		err = a.disable(ctx)
+	}
+	inspection := a.Inspect(ctx, active)
+	return target.OperationResult{Inspection: inspection, Err: redact(err, active)}
+}
+
+func compatible(input profile.Profile) (profile.Profile, error) {
+	p, err := profile.ValidateAndNormalize(input)
+	if err != nil {
+		return profile.Profile{}, err
+	}
+	if p.Mode == profile.AdvancedMode && p.AllURL != "" {
+		return profile.Profile{}, errors.New("Docker daemon Target does not support an ALL/SOCKS proxy; remove it before applying")
+	}
+	for name, raw := range map[string]string{"HTTP": p.HTTPURL, "HTTPS": p.HTTPSURL} {
+		if raw == "" {
+			continue
+		}
+		u, _ := url.Parse(raw)
+		if u.Scheme != "http" && u.Scheme != "https" {
+			return profile.Profile{}, fmt.Errorf("Docker daemon Target does not support %s proxy scheme %q", name, u.Scheme)
+		}
+	}
+	return p, nil
+}
+
+func (a *Adapter) enable(ctx context.Context, p profile.Profile) error {
+	metadata, managed, err := a.readRecovery()
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return fmt.Errorf("read Docker daemon recovery metadata: %w", err)
+	}
+	current, readErr := a.files.ReadFile(a.configuration.DaemonConfigPath)
+	if readErr != nil && !errors.Is(readErr, fs.ErrNotExist) {
+		return fmt.Errorf("read Docker daemon configuration: %w", readErr)
+	}
+	if !managed {
+		metadata.OriginalExists = readErr == nil
+		if metadata.OriginalExists {
+			metadata.Original = append([]byte(nil), current...)
+			if mode, modeErr := a.files.FileMode(a.configuration.DaemonConfigPath); modeErr == nil {
+				metadata.OriginalMode = uint32(mode.Perm())
+			} else {
+				return fmt.Errorf("inspect Docker daemon configuration permissions: %w", modeErr)
+			}
+		}
+	}
+	base := current
+	if errors.Is(readErr, fs.ErrNotExist) {
+		base = []byte("{}")
+	}
+	desired, err := mergeConfig(base, p)
+	if err != nil {
+		return fmt.Errorf("parse Docker daemon configuration before changing it: %w", err)
+	}
+	desiredFingerprint := fingerprint(desired)
+	if managed && fingerprint(current) == metadata.ConfigFingerprint && metadata.ConfigFingerprint == desiredFingerprint && metadata.RestartedFingerprint == desiredFingerprint {
+		return nil
+	}
+	metadata.ConfigFingerprint = desiredFingerprint
+	metadata.RestartedFingerprint = ""
+	if err := a.writeRecovery(metadata); err != nil {
+		return fmt.Errorf("persist Docker daemon recovery metadata before changing configuration: %w", err)
+	}
+	if fingerprint(current) != desiredFingerprint {
+		mode := os.FileMode(0o600)
+		if metadata.OriginalExists {
+			mode = os.FileMode(metadata.OriginalMode)
+		}
+		if err := a.files.AtomicWrite(a.configuration.DaemonConfigPath, desired, mode); err != nil {
+			return fmt.Errorf("write Docker daemon configuration after recovery metadata persisted: %w", err)
+		}
+	}
+	if err := a.reloadRestartInspect(ctx); err != nil {
+		return err
+	}
+	metadata.RestartedFingerprint = desiredFingerprint
+	if err := a.writeRecovery(metadata); err != nil {
+		return fmt.Errorf("record completed Docker daemon restart: %w", err)
+	}
+	return nil
+}
+
+func (a *Adapter) disable(ctx context.Context) error {
+	metadata, managed, err := a.readRecovery()
+	if errors.Is(err, fs.ErrNotExist) || !managed {
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("read Docker daemon recovery metadata: %w", err)
+	}
+	if metadata.OriginalExists {
+		current, _ := a.files.ReadFile(a.configuration.DaemonConfigPath)
+		if fingerprint(current) != fingerprint(metadata.Original) {
+			if err := a.files.AtomicWrite(a.configuration.DaemonConfigPath, metadata.Original, os.FileMode(metadata.OriginalMode)); err != nil {
+				return fmt.Errorf("restore Docker daemon configuration: %w", err)
+			}
+		}
+	} else if err := a.files.Remove(a.configuration.DaemonConfigPath); err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return fmt.Errorf("remove managed Docker daemon configuration: %w", err)
+	}
+	if err := a.reloadRestartInspect(ctx); err != nil {
+		return err
+	}
+	if err := a.files.Remove(a.configuration.RecoveryPath); err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return fmt.Errorf("remove Docker daemon recovery metadata after restart: %w", err)
+	}
+	return nil
+}
+
+func (a *Adapter) reloadRestartInspect(ctx context.Context) error {
+	if _, err := a.runner.Run(ctx, "systemctl", "daemon-reload"); err != nil {
+		return fmt.Errorf("reload systemd manager configuration: %w", err)
+	}
+	if _, err := a.runner.Run(ctx, "systemctl", "restart", service); err != nil {
+		return fmt.Errorf("restart Docker daemon: %w", err)
+	}
+	output, err := a.runner.Run(ctx, "systemctl", "is-active", service)
+	if err != nil {
+		return fmt.Errorf("inspect Docker daemon after restart: %w", err)
+	}
+	if strings.TrimSpace(string(output)) != "active" {
+		return fmt.Errorf("inspect Docker daemon after restart: service state is %q", strings.TrimSpace(string(output)))
+	}
+	return nil
+}
+
+func (a *Adapter) readRecovery() (recovery, bool, error) {
+	data, err := a.files.ReadFile(a.configuration.RecoveryPath)
+	if err != nil {
+		return recovery{}, false, err
+	}
+	var value recovery
+	if err := json.Unmarshal(data, &value); err != nil {
+		return recovery{}, true, err
+	}
+	return value, true, nil
+}
+func (a *Adapter) writeRecovery(value recovery) error {
+	data, err := json.MarshalIndent(value, "", "  ")
+	if err != nil {
+		return err
+	}
+	return a.files.AtomicWrite(a.configuration.RecoveryPath, append(data, '\n'), 0o600)
+}
+
+func mergeConfig(data []byte, p profile.Profile) ([]byte, error) {
+	var document map[string]any
+	if len(strings.TrimSpace(string(data))) == 0 {
+		data = []byte("{}")
+	}
+	if err := json.Unmarshal(data, &document); err != nil {
+		return nil, err
+	}
+	if document == nil {
+		document = map[string]any{}
+	}
+	proxies := map[string]any{}
+	if existing, ok := document["proxies"].(map[string]any); ok {
+		for key, value := range existing {
+			proxies[key] = value
+		}
+	} else if _, exists := document["proxies"]; exists {
+		return nil, errors.New("the existing proxies field is not an object")
+	}
+	setOrDelete(proxies, "http-proxy", p.HTTPURL)
+	setOrDelete(proxies, "https-proxy", p.HTTPSURL)
+	setOrDelete(proxies, "no-proxy", strings.Join(p.Bypass, ","))
+	document["proxies"] = proxies
+	output, err := json.MarshalIndent(document, "", "  ")
+	if err != nil {
+		return nil, err
+	}
+	return append(output, '\n'), nil
+}
+func setOrDelete(values map[string]any, key, value string) {
+	if value == "" {
+		delete(values, key)
+	} else {
+		values[key] = value
+	}
+}
+func configMatchesProfile(data []byte, p profile.Profile) bool {
+	var document map[string]any
+	if json.Unmarshal(data, &document) != nil {
+		return false
+	}
+	proxies, ok := document["proxies"].(map[string]any)
+	if !ok {
+		return false
+	}
+	return stringValue(proxies["http-proxy"]) == p.HTTPURL && stringValue(proxies["https-proxy"]) == p.HTTPSURL && stringValue(proxies["no-proxy"]) == strings.Join(p.Bypass, ",")
+}
+func recognizesProxy(data []byte) bool {
+	var document map[string]any
+	if json.Unmarshal(data, &document) != nil {
+		return false
+	}
+	proxies, ok := document["proxies"].(map[string]any)
+	if !ok {
+		return false
+	}
+	for _, key := range []string{"http-proxy", "https-proxy", "no-proxy"} {
+		if stringValue(proxies[key]) != "" {
+			return true
+		}
+	}
+	return false
+}
+func stringValue(value any) string   { result, _ := value.(string); return result }
+func fingerprint(data []byte) string { sum := sha256.Sum256(data); return hex.EncodeToString(sum[:]) }
+
+type redactedError struct {
+	message string
+	class   error
+}
+
+func (e *redactedError) Error() string       { return e.message }
+func (e *redactedError) Is(other error) bool { return e.class != nil && errors.Is(e.class, other) }
+func redact(err error, active *profile.Profile) error {
+	if err == nil {
+		return nil
+	}
+	message := profile.RedactText(err.Error())
+	if active != nil {
+		for _, raw := range []string{active.SingleURL, active.HTTPURL, active.HTTPSURL, active.AllURL} {
+			if raw == "" {
+				continue
+			}
+			message = strings.ReplaceAll(message, raw, profile.ObscureURL(raw))
+			if parsed, parseErr := url.Parse(raw); parseErr == nil && parsed.User != nil {
+				if password, ok := parsed.User.Password(); ok && password != "" {
+					message = strings.ReplaceAll(message, password, "REDACTED")
+				}
+			}
+		}
+	}
+	var class error
+	for _, safe := range []error{os.ErrPermission, fs.ErrNotExist, fs.ErrExist, context.Canceled, context.DeadlineExceeded} {
+		if errors.Is(err, safe) {
+			class = safe
+			break
+		}
+	}
+	return &redactedError{message: message, class: class}
+}
+
+// Paths expose configured effects for diagnostics and hermetic tests.
+func (a *Adapter) DaemonConfigPath() string { return filepath.Clean(a.configuration.DaemonConfigPath) }
+func (a *Adapter) RecoveryPath() string     { return filepath.Clean(a.configuration.RecoveryPath) }

internal/dockerdaemon/dockerdaemon_test.go

@@ -0,0 +1,340 @@
+package dockerdaemon_test
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+
+	"proxyctl/internal/dockerdaemon"
+	"proxyctl/internal/profile"
+	"proxyctl/internal/target"
+	"proxyctl/internal/target/targettest"
+)
+
+type recorder struct{ events []string }
+
+type fakeRunner struct {
+	recorder *recorder
+	show     string
+	fail     map[string]error
+}
+
+func (r *fakeRunner) Run(_ context.Context, name string, args ...string) ([]byte, error) {
+	command := strings.Join(append([]string{name}, args...), " ")
+	r.recorder.events = append(r.recorder.events, command)
+	if err := r.fail[command]; err != nil {
+		return nil, err
+	}
+	if strings.Contains(command, " show ") {
+		return []byte(r.show), nil
+	}
+	if strings.Contains(command, " is-active ") {
+		return []byte("active\n"), nil
+	}
+	return nil, nil
+}
+
+type recordingFS struct{ recorder *recorder }
+
+func (f recordingFS) ReadFile(path string) ([]byte, error) { return os.ReadFile(path) }
+func (f recordingFS) FileMode(path string) (os.FileMode, error) {
+	info, err := os.Stat(path)
+	if err != nil {
+		return 0, err
+	}
+	return info.Mode().Perm(), nil
+}
+func (f recordingFS) AtomicWrite(path string, data []byte, mode os.FileMode) error {
+	f.recorder.events = append(f.recorder.events, "write "+filepath.Base(path))
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+		return err
+	}
+	temporary := path + ".tmp"
+	if err := os.WriteFile(temporary, data, mode); err != nil {
+		return err
+	}
+	return os.Rename(temporary, path)
+}
+func (f recordingFS) Remove(path string) error {
+	f.recorder.events = append(f.recorder.events, "remove "+filepath.Base(path))
+	return os.Remove(path)
+}
+
+func fixture(t *testing.T) (*dockerdaemon.Adapter, *recorder, string, string, *fakeRunner) {
+	t.Helper()
+	directory := t.TempDir()
+	daemonPath := filepath.Join(directory, "etc", "docker", "daemon.json")
+	recoveryPath := filepath.Join(directory, "state", "docker-daemon.json")
+	record := &recorder{}
+	runner := &fakeRunner{recorder: record, show: "LoadState=loaded\nFragmentPath=/lib/systemd/system/docker.service\n", fail: map[string]error{}}
+	adapter := dockerdaemon.New(dockerdaemon.Configuration{DaemonConfigPath: daemonPath, RecoveryPath: recoveryPath, TrustedRoot: directory}, recordingFS{recorder: record}, runner)
+	return adapter, record, daemonPath, recoveryPath, runner
+}
+
+func activeProfile() *profile.Profile {
+	return &profile.Profile{Name: "office", Mode: profile.AdvancedMode, HTTPURL: "http://alice:secret@proxy.example:8080", HTTPSURL: "https://proxy.example:8443", Bypass: []string{"localhost", ".example.com", "10.0.0.0/8", "2001:db8::1"}}
+}
+
+type faultFS struct {
+	recordingFS
+	permission       bool
+	failDaemon       bool
+	failRecoveryOnce bool
+}
+
+func (f *faultFS) AtomicWrite(path string, data []byte, mode os.FileMode) error {
+	if f.permission {
+		return os.ErrPermission
+	}
+	if f.failDaemon && filepath.Base(path) == "daemon.json" {
+		return errors.New("write failed")
+	}
+	if f.failRecoveryOnce && filepath.Base(path) == "docker-daemon.json" {
+		f.failRecoveryOnce = false
+		return errors.New("secret recovery failure")
+	}
+	return f.recordingFS.AtomicWrite(path, data, mode)
+}
+
+func TestDockerDaemonRunsReusableTargetContract(t *testing.T) {
+	targettest.Run(t, func(t *testing.T) targettest.Fixture {
+		a, _, daemonPath, _, _ := fixture(t)
+		return targettest.Fixture{
+			Target: a, Active: activeProfile(), Secret: "secret",
+			MakeExternal: func(t *testing.T) {
+				if err := os.MkdirAll(filepath.Dir(daemonPath), 0o700); err != nil {
+					t.Fatal(err)
+				}
+				if err := os.WriteFile(daemonPath, []byte(`{"proxies":{"http-proxy":"http://external.example:8080"}}`), 0o600); err != nil {
+					t.Fatal(err)
+				}
+			},
+			MakeDrifted: func(t *testing.T) {
+				if err := os.WriteFile(daemonPath, []byte(`{"proxies":{"http-proxy":"http://changed.example:8080"}}`), 0o600); err != nil {
+					t.Fatal(err)
+				}
+			},
+			PermissionFailure: func(t *testing.T) target.OperationResult {
+				failed, record, _, _, failedRunner := fixture(t)
+				files := &faultFS{recordingFS: recordingFS{recorder: record}, permission: true}
+				failed = dockerdaemon.New(dockerdaemon.Configuration{DaemonConfigPath: failed.DaemonConfigPath(), RecoveryPath: failed.RecoveryPath(), TrustedRoot: filepath.Dir(filepath.Dir(failed.DaemonConfigPath()))}, files, failedRunner)
+				return failed.SetDesired(context.Background(), true, activeProfile())
+			},
+			PartialFailure: func(t *testing.T) target.OperationResult {
+				failed, record, _, _, failedRunner := fixture(t)
+				files := &faultFS{recordingFS: recordingFS{recorder: record}, failDaemon: true}
+				failed = dockerdaemon.New(dockerdaemon.Configuration{DaemonConfigPath: failed.DaemonConfigPath(), RecoveryPath: failed.RecoveryPath()}, files, failedRunner)
+				return failed.SetDesired(context.Background(), true, activeProfile())
+			},
+			RedactionFailure: func(t *testing.T) target.OperationResult {
+				failed, _, _, _, failedRunner := fixture(t)
+				failedRunner.fail["systemctl daemon-reload"] = errors.New("http://alice:secret@proxy.example:8080")
+				return failed.SetDesired(context.Background(), true, activeProfile())
+			},
+			RecoveryRetry: func(t *testing.T) (target.OperationResult, target.OperationResult, target.OperationResult) {
+				failed, record, daemon, recovery, failedRunner := fixture(t)
+				if err := os.MkdirAll(filepath.Dir(daemon), 0o700); err != nil {
+					t.Fatal(err)
+				}
+				if err := os.WriteFile(daemon, []byte(`{"proxies":{"http-proxy":"http://external.example:8080"}}`), 0o600); err != nil {
+					t.Fatal(err)
+				}
+				files := &faultFS{recordingFS: recordingFS{recorder: record}, failRecoveryOnce: true}
+				failed = dockerdaemon.New(dockerdaemon.Configuration{DaemonConfigPath: daemon, RecoveryPath: recovery}, files, failedRunner)
+				first := failed.SetDesired(context.Background(), true, activeProfile())
+				retry := failed.SetDesired(context.Background(), true, activeProfile())
+				disabled := failed.SetDesired(context.Background(), false, nil)
+				return first, retry, disabled
+			},
+		}
+	})
+}
+
+func TestDockerDaemonAvailabilityDescriptionAndConfirmation(t *testing.T) {
+	a, _, _, _, runner := fixture(t)
+	if got := a.Availability(context.Background()); !got.Available || !strings.Contains(got.Evidence, "systemd") {
+		t.Fatalf("availability = %#v", got)
+	}
+	description := a.Description()
+	for _, phrase := range []string{"registry", "not container network traffic", "restart", "permission"} {
+		if !strings.Contains(strings.ToLower(description.Summary+" "+description.Details), phrase) {
+			t.Errorf("description misses %q: %#v", phrase, description)
+		}
+	}
+	if warning := a.Confirmation(true); !strings.Contains(strings.ToLower(warning), "restart") || !strings.Contains(strings.ToLower(warning), "running") {
+		t.Fatalf("confirmation = %q", warning)
+	}
+	runner.show = "LoadState=not-found\nFragmentPath=\n"
+	if got := a.Availability(context.Background()); got.Available || !strings.Contains(got.Evidence, "not detected") {
+		t.Fatalf("unsupported availability = %#v", got)
+	}
+}
+
+func TestDockerDaemonEnableOrdersManagedWriteReloadRestartAndPostInspect(t *testing.T) {
+	a, record, daemonPath, _, _ := fixture(t)
+	result := a.SetDesired(context.Background(), true, activeProfile())
+	if result.Err != nil || result.Inspection.State != target.Enabled {
+		t.Fatalf("enable = %#v", result)
+	}
+	wantOrder := []string{"write docker-daemon.json", "write daemon.json", "systemctl daemon-reload", "systemctl restart docker.service", "systemctl is-active docker.service", "write docker-daemon.json"}
+	assertSubsequence(t, record.events, wantOrder)
+	var config map[string]any
+	data, err := os.ReadFile(daemonPath)
+	if err != nil || json.Unmarshal(data, &config) != nil {
+		t.Fatalf("daemon config: %v %s", err, data)
+	}
+	proxies := config["proxies"].(map[string]any)
+	if proxies["http-proxy"] != activeProfile().HTTPURL || proxies["https-proxy"] != activeProfile().HTTPSURL || !strings.Contains(proxies["no-proxy"].(string), "10.0.0.0/8") {
+		t.Fatalf("managed proxies = %#v", proxies)
+	}
+
+	record.events = nil
+	second := a.SetDesired(context.Background(), true, activeProfile())
+	if second.Err != nil || second.Inspection.State != target.Enabled || len(mutationEvents(record.events)) != 0 {
+		t.Fatalf("idempotent enable = %#v, events=%v", second, record.events)
+	}
+}
+
+func TestDockerDaemonPreservesAndRestoresExistingConfiguration(t *testing.T) {
+	a, _, daemonPath, recoveryPath, _ := fixture(t)
+	original := []byte("{\n  \"log-level\": \"debug\",\n  \"proxies\": {\"http-proxy\": \"http://prior.example:3128\"}\n}\n")
+	if err := os.MkdirAll(filepath.Dir(daemonPath), 0o700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(daemonPath, original, 0o640); err != nil {
+		t.Fatal(err)
+	}
+	if got := a.Inspect(context.Background(), activeProfile()).State; got != target.External {
+		t.Fatalf("initial = %s", got)
+	}
+	if got := a.SetDesired(context.Background(), true, activeProfile()); got.Err != nil {
+		t.Fatal(got.Err)
+	}
+	if got := a.SetDesired(context.Background(), false, nil); got.Err != nil || got.Inspection.State != target.External {
+		t.Fatalf("disable = %#v", got)
+	}
+	restored, _ := os.ReadFile(daemonPath)
+	if !reflect.DeepEqual(restored, original) {
+		t.Fatalf("restored:\n%s\nwant:\n%s", restored, original)
+	}
+	if info, err := os.Stat(daemonPath); err != nil || info.Mode().Perm() != 0o640 {
+		t.Fatalf("restored mode = %v, %v", info, err)
+	}
+	if _, err := os.Stat(recoveryPath); !errors.Is(err, os.ErrNotExist) {
+		t.Fatalf("recovery remains: %v", err)
+	}
+}
+
+func TestDockerDaemonRestartFailureIsRedactedTruthfulAndRetryable(t *testing.T) {
+	a, record, _, _, runner := fixture(t)
+	restart := "systemctl restart docker.service"
+	runner.fail[restart] = fmt.Errorf("restart exposed http://alice:secret@proxy.example:8080")
+	first := a.SetDesired(context.Background(), true, activeProfile())
+	if first.Err == nil || strings.Contains(first.Err.Error(), "secret") || first.Inspection.State != target.Enabled {
+		t.Fatalf("restart failure = %#v", first)
+	}
+	delete(runner.fail, restart)
+	record.events = nil
+	retry := a.SetDesired(context.Background(), true, activeProfile())
+	if retry.Err != nil || retry.Inspection.State != target.Enabled {
+		t.Fatalf("retry = %#v", retry)
+	}
+	if contains(record.events, "write daemon.json") || !contains(record.events, restart) {
+		t.Fatalf("retry events = %v", record.events)
+	}
+}
+
+func TestDockerDaemonRejectsIncompatibleProfileBeforeMutation(t *testing.T) {
+	for _, p := range []*profile.Profile{
+		{Name: "socks", Mode: profile.SingleMode, SingleURL: "socks5://proxy.example:1080"},
+		{Name: "all", Mode: profile.AdvancedMode, HTTPURL: "http://proxy.example:8080", AllURL: "http://proxy.example:8080"},
+		{Name: "bypass", Mode: profile.AdvancedMode, HTTPURL: "http://proxy.example:8080", Bypass: []string{"*"}},
+	} {
+		t.Run(p.Name, func(t *testing.T) {
+			a, record, _, _, _ := fixture(t)
+			result := a.SetDesired(context.Background(), true, p)
+			if result.Err == nil || len(mutationEvents(record.events)) != 0 || result.Inspection.State != target.Disabled {
+				t.Fatalf("incompatible result = %#v events=%v", result, record.events)
+			}
+		})
+	}
+}
+
+func TestDockerDaemonNeverEscalatesAndReportsPermissionNormally(t *testing.T) {
+	a, record, _, _, runner := fixture(t)
+	runner.fail["systemctl daemon-reload"] = os.ErrPermission
+	got := a.SetDesired(context.Background(), true, activeProfile())
+	if got.Err == nil || !errors.Is(got.Err, os.ErrPermission) || got.Inspection.State != target.Enabled {
+		t.Fatalf("permission = %#v", got)
+	}
+	for _, event := range record.events {
+		if strings.Contains(event, "sudo") || strings.Contains(event, "pkexec") {
+			t.Fatalf("privilege escalation: %v", record.events)
+		}
+	}
+}
+
+func TestDockerDaemonInspectionHasAllFourStates(t *testing.T) {
+	a, _, daemonPath, _, _ := fixture(t)
+	ctx := context.Background()
+	if got := a.Inspect(ctx, activeProfile()).State; got != target.Disabled {
+		t.Fatalf("disabled = %s", got)
+	}
+	if err := os.MkdirAll(filepath.Dir(daemonPath), 0o700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(daemonPath, []byte(`{"proxies":{"http-proxy":"http://external.example:8080"}}`), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if got := a.Inspect(ctx, activeProfile()).State; got != target.External {
+		t.Fatalf("external = %s", got)
+	}
+	if got := a.SetDesired(ctx, true, activeProfile()); got.Err != nil {
+		t.Fatal(got.Err)
+	}
+	if got := a.Inspect(ctx, activeProfile()).State; got != target.Enabled {
+		t.Fatalf("enabled = %s", got)
+	}
+	if err := os.WriteFile(daemonPath, []byte(`{"proxies":{"http-proxy":"http://changed.example:8080"}}`), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if got := a.Inspect(ctx, activeProfile()).State; got != target.Drifted {
+		t.Fatalf("drifted = %s", got)
+	}
+}
+
+func assertSubsequence(t *testing.T, got, want []string) {
+	t.Helper()
+	index := 0
+	for _, event := range got {
+		if index < len(want) && event == want[index] {
+			index++
+		}
+	}
+	if index != len(want) {
+		t.Fatalf("events %v do not contain ordered %v", got, want)
+	}
+}
+func mutationEvents(events []string) []string {
+	var result []string
+	for _, event := range events {
+		if strings.HasPrefix(event, "write ") || strings.HasPrefix(event, "remove ") || strings.Contains(event, "daemon-reload") || strings.Contains(event, " restart ") {
+			result = append(result, event)
+		}
+	}
+	return result
+}
+func contains(values []string, want string) bool {
+	for _, value := range values {
+		if value == want {
+			return true
+		}
+	}
+	return false
+}

internal/shell/shell.go

@@ -183,9 +183,10 @@ func (a *Adapter) Availability(context.Context) target.Availability {
 		return target.Availability{Evidence: "Shell Target requires Bash or Zsh; neither was detected"}
 	}
 }
-func (a *Adapter) EnvironmentPath() string { return a.configuration.EnvironmentFile }
-func (a *Adapter) RecoveryPath() string    { return a.configuration.RecoveryFile }
-func (a *Adapter) StartupPath() string     { return a.configuration.StartupFile }
+func (a *Adapter) Confirmation(bool) string { return "" }
+func (a *Adapter) EnvironmentPath() string  { return a.configuration.EnvironmentFile }
+func (a *Adapter) RecoveryPath() string     { return a.configuration.RecoveryFile }
+func (a *Adapter) StartupPath() string      { return a.configuration.StartupFile }
 
 func (a *Adapter) Inspect(_ context.Context, active *profile.Profile) target.Inspection {
 	metadata, managed, metadataErr := a.readRecovery()

internal/target/target.go

@@ -44,5 +44,8 @@ type Target interface {
 	Description() Description
 	Availability(context.Context) Availability
 	Inspect(context.Context, *profile.Profile) Inspection
+	// Confirmation returns a warning that must be accepted before SetDesired.
+	// An empty string means the operation needs no confirmation.
+	Confirmation(enabled bool) string
 	SetDesired(context.Context, bool, *profile.Profile) OperationResult
 }

internal/target/target_test.go

@@ -20,6 +20,7 @@ func (seamTarget) Availability(context.Context) target.Availability {
 func (seamTarget) Inspect(context.Context, *profile.Profile) target.Inspection {
 	return target.Inspection{State: target.Disabled, Evidence: "absent"}
 }
+func (seamTarget) Confirmation(bool) string { return "" }
 func (seamTarget) SetDesired(context.Context, bool, *profile.Profile) target.OperationResult {
 	return target.OperationResult{Inspection: target.Inspection{State: target.Enabled}}
 }

internal/tui/model.go

@@ -26,14 +26,15 @@ type formState struct {
 }
 
 type Model struct {
-	application app.Module
-	snapshot    app.Snapshot
-	page        page
-	selected    int
-	form        formState
-	confirm     bool
-	status      string
-	applying    bool
+	application   app.Module
+	snapshot      app.Snapshot
+	page          page
+	selected      int
+	form          formState
+	confirm       bool
+	targetConfirm *app.Intent
+	status        string
+	applying      bool
 }
 
 type targetOperationDone struct {
@@ -50,9 +51,18 @@ func (m Model) Update(message tea.Msg) (tea.Model, tea.Cmd) {
 	if completed, ok := message.(targetOperationDone); ok {
 		m.applying = false
 		m.snapshot = completed.result.Snapshot
-		if completed.result.Err != nil {
+		if completed.result.Confirmation != "" {
+			intent := app.Intent{Kind: app.SetTargetDesired}
+			if m.targetConfirm != nil {
+				intent = *m.targetConfirm
+			}
+			m.targetConfirm = &intent
+			m.status = completed.result.Confirmation
+		} else if completed.result.Err != nil {
+			m.targetConfirm = nil
 			m.status = "\x1b[31mError: " + completed.result.Err.Error() + "\x1b[0m"
 		} else {
+			m.targetConfirm = nil
 			m.status = completed.result.Notice
 		}
 		return m, nil
@@ -74,6 +84,21 @@ func (m Model) Update(message tea.Msg) (tea.Model, tea.Cmd) {
 }
 
 func (m Model) updateMain(key tea.KeyMsg) (tea.Model, tea.Cmd) {
+	if m.targetConfirm != nil && !m.applying {
+		switch key.String() {
+		case "y":
+			intent := *m.targetConfirm
+			intent.Confirm = true
+			m.targetConfirm = nil
+			m.applying = true
+			m.status = ""
+			return m, func() tea.Msg { return targetOperationDone{result: m.application.Dispatch(intent)} }
+		case "n", "esc", "q":
+			m.targetConfirm = nil
+			m.status = ""
+		}
+		return m, nil
+	}
 	targets := m.availableTargets()
 	switch key.String() {
 	case "p":
@@ -93,8 +118,10 @@ func (m Model) updateMain(key tea.KeyMsg) (tea.Model, tea.Cmd) {
 			desired := selected.State != target.Enabled
 			m.applying = true
 			m.status = ""
+			intent := app.Intent{Kind: app.SetTargetDesired, TargetID: selected.ID, Enabled: desired}
+			m.targetConfirm = &intent
 			return m, func() tea.Msg {
-				return targetOperationDone{result: m.application.Dispatch(app.Intent{Kind: app.SetTargetDesired, TargetID: selected.ID, Enabled: desired})}
+				return targetOperationDone{result: m.application.Dispatch(intent)}
 			}
 		}
 	case "q", "esc", "ctrl+c":
@@ -288,7 +315,11 @@ func (m Model) mainView() string {
 			fmt.Fprintf(&b, "\nUnavailable %s: %s\n", item.Description.Name, item.AvailabilityEvidence)
 		}
 	}
-	b.WriteString("\nSpace: toggle  ↑/k ↓/j: select  p: manage Proxy Profiles  q/Esc: quit\n")
+	if m.targetConfirm != nil && !m.applying {
+		b.WriteString("\ny: confirm  n/Esc: cancel\n")
+	} else {
+		b.WriteString("\nSpace: toggle  ↑/k ↓/j: select  p: manage Proxy Profiles  q/Esc: quit\n")
+	}
 	if m.status != "" {
 		fmt.Fprintf(&b, "\n%s\n", m.status)
 	}

internal/tui/target_test.go

@@ -49,6 +49,42 @@ func TestTargetPanelShowsOnlyAvailableTargetsAndAppliesAsynchronously(t *testing
 	}
 }
 
+func TestTargetRestartConfirmationCancelsWithoutConfirmedMutation(t *testing.T) {
+	initial := app.Snapshot{ActiveProfile: "office", Targets: []app.TargetSnapshot{{ID: "docker-daemon", Description: target.Description{Name: "Docker daemon"}, Available: true, State: target.Disabled}}}
+	module := &targetModule{snapshot: initial, result: app.Result{Snapshot: initial, Confirmation: "Docker will restart immediately and may disrupt running work."}}
+	model := NewModel(module)
+	updated, command := model.Update(tea.KeyMsg{Type: tea.KeySpace})
+	model = updated.(Model)
+	updated, _ = model.Update(command())
+	model = updated.(Model)
+	if !strings.Contains(model.View(), "restart immediately") || len(module.intents) != 1 || module.intents[0].Confirm {
+		t.Fatalf("warning = intents %#v\n%s", module.intents, model.View())
+	}
+	updated, command = model.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'n'}})
+	model = updated.(Model)
+	if command != nil || len(module.intents) != 1 || strings.Contains(model.View(), "restart immediately") {
+		t.Fatalf("cancel mutated = intents %#v\n%s", module.intents, model.View())
+	}
+
+	updated, command = model.Update(tea.KeyMsg{Type: tea.KeySpace})
+	model = updated.(Model)
+	updated, _ = model.Update(command())
+	model = updated.(Model)
+	module.result = app.Result{
+		Snapshot: app.Snapshot{ActiveProfile: "office", Targets: []app.TargetSnapshot{{ID: "docker-daemon", Description: target.Description{Name: "Docker daemon"}, Available: true, State: target.Enabled}}},
+		Notice:   "Docker daemon Target is now Enabled",
+	}
+	updated, command = model.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'y'}})
+	model = updated.(Model)
+	if command == nil {
+		t.Fatal("confirmation did not start operation")
+	}
+	_ = command()
+	if len(module.intents) != 3 || !module.intents[2].Confirm {
+		t.Fatalf("confirmed intents = %#v", module.intents)
+	}
+}
+
 func TestUnavailableShellIsOutsideMainListWithDetectionExplanation(t *testing.T) {
 	module := &targetModule{snapshot: app.Snapshot{Targets: []app.TargetSnapshot{
 		{ID: "shell", Description: target.Description{Name: "Shell"}, Available: false, AvailabilityEvidence: "Shell Target requires Bash or Zsh; neither was detected"},