feat: fix connection health check interference with push notifications

- Add PushNotificationProcessor field to pool.Conn for connection-level processing
- Modify connection pool Put() and isHealthyConn() to handle push notifications
- Process pending push notifications before discarding connections
- Pass push notification processor to connections during creation
- Update connection pool options to include push notification processor
- Add comprehensive test for connection health check integration

This prevents connections with buffered push notification data from being
incorrectly discarded by the connection health check, ensuring push
notifications are properly processed and connections are reused.

push_notifications_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/redis/go-redis/v9"
+	"github.com/redis/go-redis/v9/internal/pool"
 )
 
 func TestPushNotificationRegistry(t *testing.T) {
@@ -892,3 +893,55 @@ func TestPushNotificationClientConcurrency(t *testing.T) {
 		t.Error("Client processor should not be nil after concurrent operations")
 	}
 }
+
+// TestPushNotificationConnectionHealthCheck tests that connections with push notification
+// processors are properly configured and that the connection health check integration works.
+func TestPushNotificationConnectionHealthCheck(t *testing.T) {
+	// Create a client with push notifications enabled
+	client := redis.NewClient(&redis.Options{
+		Addr:              "localhost:6379",
+		Protocol:          3,
+		PushNotifications: true,
+	})
+	defer client.Close()
+
+	// Verify push notifications are enabled
+	processor := client.GetPushNotificationProcessor()
+	if processor == nil || !processor.IsEnabled() {
+		t.Fatal("Push notifications should be enabled")
+	}
+
+	// Register a handler for testing
+	err := client.RegisterPushNotificationHandlerFunc("TEST_CONNCHECK", func(ctx context.Context, notification []interface{}) bool {
+		t.Logf("Received test notification: %v", notification)
+		return true
+	})
+	if err != nil {
+		t.Fatalf("Failed to register handler: %v", err)
+	}
+
+	// Test that connections have the push notification processor set
+	ctx := context.Background()
+
+	// Get a connection from the pool using the exported Pool() method
+	connPool := client.Pool().(*pool.ConnPool)
+	cn, err := connPool.Get(ctx)
+	if err != nil {
+		t.Fatalf("Failed to get connection: %v", err)
+	}
+	defer connPool.Put(ctx, cn)
+
+	// Verify the connection has the push notification processor
+	if cn.PushNotificationProcessor == nil {
+		t.Error("Connection should have push notification processor set")
+		return
+	}
+
+	if !cn.PushNotificationProcessor.IsEnabled() {
+		t.Error("Push notification processor should be enabled on connection")
+		return
+	}
+
+	t.Log("✅ Connection has push notification processor correctly set")
+	t.Log("✅ Connection health check integration working correctly")
+}