fix(ios): stop the app before clearing its state

Launch terminated and then cleared; the clear moved to construction and
left nothing stopping the app first. The container wipe deletes files a
live app still holds open, and the CI ios leg passes no app path so the
wipe is the path it takes. simctl stops it, since the clear now runs
before any automation session exists. On a device the uninstall that is
its only clear takes the running app with it.

internal/driver/ioscompanion/device.go

@@ -111,13 +111,17 @@ func NewDevice(ctx context.Context, options DeviceOptions) (*Driver, error) {
 
 	// Device seams: clear-state reinstalls via devicectl; the container reset and
 	// paste grant are simulator-only and become no-ops. The runner types
-	// natively, so no paste prompt is ever hit.
+	// natively, so no paste prompt is ever hit. Stopping the app before the
+	// clear is a no-op too: devicectl addresses processes by pid rather than by
+	// bundle, and the uninstall that is the device's only clear takes the
+	// running app with it, which is what a terminate here would be for.
 	d.reinstallApp = options.reinstallApp
 	if d.reinstallApp == nil {
 		d.reinstallApp = d.devicectlReinstall
 	}
 	d.resetContainer = d.deviceResetContainerUnsupported
 	d.grantPaste = func(context.Context) error { return nil }
+	d.terminateApp = func(context.Context) error { return nil }
 	d.restart = d.respawnDevice
 	d.processContext, d.processCancel = context.WithCancel(ctx)
 

internal/driver/ioscompanion/driver.go

@@ -91,6 +91,7 @@ type Options struct {
 	dialRunner     func(address string) (transport.Companion, error)
 	reinstallApp   func(ctx context.Context) error
 	resetContainer func(ctx context.Context) error
+	terminateApp   func(ctx context.Context) error
 }
 
 // Driver implements driver.DeviceDriver against an iOS simulator companion.
@@ -136,6 +137,10 @@ type Driver struct {
 	// A seam so tests skip the simctl shell-outs.
 	reinstallApp func(ctx context.Context) error
 
+	// terminateApp stops the app before its state is cleared. A seam so tests
+	// skip the simctl shell-out.
+	terminateApp func(ctx context.Context) error
+
 	// grantPaste pre-authorizes the app's pasteboard access. A seam so tests
 	// skip the sqlite shell-out.
 	grantPaste func(ctx context.Context) error
@@ -237,6 +242,7 @@ func New(ctx context.Context, options Options) (*Driver, error) {
 		dialRunner:               options.dialRunner,
 		reinstallApp:             options.reinstallApp,
 		resetContainer:           options.resetContainer,
+		terminateApp:             options.terminateApp,
 		hybrid:                   hybridCompanionEnabled(),
 	}
 	if driverInstance.spawnChild == nil {
@@ -271,6 +277,9 @@ func New(ctx context.Context, options Options) (*Driver, error) {
 	if driverInstance.reinstallApp == nil {
 		driverInstance.reinstallApp = driverInstance.simctlReinstall
 	}
+	if driverInstance.terminateApp == nil {
+		driverInstance.terminateApp = driverInstance.simctlTerminate
+	}
 	driverInstance.grantPaste = driverInstance.grantPasteboardAccess
 	driverInstance.processContext, driverInstance.processCancel = context.WithCancel(ctx)
 
@@ -619,6 +628,11 @@ func (d *Driver) lifecycleCompanion() transport.Companion {
 // container and warns once that a full reinstall needs the app path. Called
 // only from construction, before any automation session is attached to the app.
 func (d *Driver) clearAppState(ctx context.Context) error {
+	// Nothing may be writing to the state while it goes, which is the ordering
+	// Launch used to hold: uninstall copes with a running app, deleting the
+	// data container out from under one does not. Best effort, because an app
+	// that is not running reports a failure that means nothing here.
+	_ = d.terminateApp(ctx)
 	if d.appPath != "" {
 		if err := d.reinstallApp(ctx); err != nil {
 			return fmt.Errorf("reinstall %s: %w", d.appPath, err)
@@ -650,6 +664,18 @@ func (d *Driver) simctlReinstall(ctx context.Context) error {
 	return nil
 }
 
+// simctlTerminate stops the app under test. Launch used to terminate through
+// the automation session before clearing; the clear now runs before any session
+// exists, so simctl is what is left to stop the app with. An app that is not
+// running reports a failure that means nothing to the caller, which is why
+// clearAppState treats this as best effort.
+func (d *Driver) simctlTerminate(ctx context.Context) error {
+	if output, err := exec.CommandContext(ctx, "xcrun", "simctl", "terminate", d.udid, d.bundleID).CombinedOutput(); err != nil {
+		return fmt.Errorf("simctl terminate %s: %w: %s", d.bundleID, err, strings.TrimSpace(string(output)))
+	}
+	return nil
+}
+
 // grantPasteboardAccess authorizes the app to read the pasteboard without the
 // iOS permission prompt, by writing an allow row into the simulator's privacy
 // (TCC) database. This is the simulator counterpart to `simctl privacy grant`,