refactor(18-graceful-shutdown): harden mock shutdown lifecycle in internal/mock

internal/mock/integration.go

@@ -14,6 +14,7 @@ import (
 
 var (
 	dataMu        sync.RWMutex
+	setEnabledMu  sync.Mutex
 	mockData      models.StateSnapshot
 	mockAlerts    []models.Alert
 	mockConfig    = DefaultConfig
@@ -44,6 +45,9 @@ func SetEnabled(enable bool) {
 }
 
 func setEnabled(enable bool, fromInit bool) {
+	setEnabledMu.Lock()
+	defer setEnabledMu.Unlock()
+
 	current := enabled.Load()
 	if current == enable {
 		// Still update env so other processes see the latest value when not invoked from init.
@@ -111,7 +115,12 @@ func disableMockMode() {
 		return
 	}
 	enabled.Store(false)
-	stopUpdateLoopLocked()
+	stopUpdateLoopSignalLocked()
+	dataMu.Unlock()
+
+	waitForUpdateLoopStop()
+
+	dataMu.Lock()
 	mockData = models.StateSnapshot{}
 	mockAlerts = nil
 	dataMu.Unlock()
@@ -142,6 +151,11 @@ func startUpdateLoopLocked() {
 }
 
 func stopUpdateLoopLocked() {
+	stopUpdateLoopSignalLocked()
+	waitForUpdateLoopStop()
+}
+
+func stopUpdateLoopSignalLocked() {
 	if ch := stopUpdatesCh; ch != nil {
 		close(ch)
 		stopUpdatesCh = nil
@@ -150,7 +164,9 @@ func stopUpdateLoopLocked() {
 		ticker.Stop()
 		updateTicker = nil
 	}
-	// Wait for the update goroutine to exit
+}
+
+func waitForUpdateLoopStop() {
 	updateLoopWg.Wait()
 }
 

internal/mock/integration_shutdown_test.go

@@ -0,0 +1,38 @@
+package mock
+
+import (
+	"testing"
+	"time"
+)
+
+func TestSetEnabledDisableDoesNotDeadlockWhenLoopNeedsStateLock(t *testing.T) {
+	SetEnabled(false)
+	t.Cleanup(func() {
+		SetEnabled(false)
+	})
+
+	dataMu.Lock()
+	enabled.Store(true)
+	stopUpdatesCh = make(chan struct{})
+	updateTicker = time.NewTicker(time.Hour)
+	updateLoopWg.Add(1)
+	go func(stop <-chan struct{}) {
+		defer updateLoopWg.Done()
+		<-stop
+		dataMu.Lock()
+		dataMu.Unlock()
+	}(stopUpdatesCh)
+	dataMu.Unlock()
+
+	done := make(chan struct{})
+	go func() {
+		SetEnabled(false)
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatal("SetEnabled(false) timed out waiting for update loop shutdown")
+	}
+}

pkg/server/server.go

@@ -23,7 +23,7 @@ import (
 	"github.com/rcourtman/pulse-go-rewrite/internal/license"
 	"github.com/rcourtman/pulse-go-rewrite/internal/license/conversion"
 	"github.com/rcourtman/pulse-go-rewrite/internal/logging"
-	_ "github.com/rcourtman/pulse-go-rewrite/internal/mock" // Import for init() to run
+	"github.com/rcourtman/pulse-go-rewrite/internal/mock"
 	"github.com/rcourtman/pulse-go-rewrite/internal/monitoring"
 	"github.com/rcourtman/pulse-go-rewrite/internal/websocket"
 	"github.com/rcourtman/pulse-go-rewrite/pkg/audit"
@@ -443,6 +443,11 @@ shutdown:
 	// Stop AI chat service (kills sidecar process group)
 	router.StopAIChat(shutdownCtx)
 
+	// Ensure mock-mode background update ticker is stopped before process exit.
+	if mock.IsMockEnabled() {
+		mock.SetEnabled(false)
+	}
+
 	cancel()
 	reloadableMonitor.Stop()