From 0f4c0ec4b16dfd79e06d29b7e5553afae23b4341 Mon Sep 17 00:00:00 2001
From: Yassine Bounekhla <56373201+rudream@users.noreply.github.com>
Date: Wed, 28 Jan 2026 22:21:04 +0700
Subject: [PATCH] fix filtering by no upgrader (#63184)

---
 lib/cache/inventory/inventory_cache_test.go   | 42 +++++++++++++++++--
 lib/web/inventory.go                          |  9 +++-
 .../teleport/src/Instances/Instances.tsx      |  2 +-
 3 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/lib/cache/inventory/inventory_cache_test.go b/lib/cache/inventory/inventory_cache_test.go
index 98be7630b8f..d3381a29129 100644
--- a/lib/cache/inventory/inventory_cache_test.go
+++ b/lib/cache/inventory/inventory_cache_test.go
@@ -897,6 +897,18 @@ func TestInventoryCacheFiltering(t *testing.T) {
 					ExternalUpgrader: "kube",
 				},
 			},
+			{
+				ResourceHeader: types.ResourceHeader{
+					Metadata: types.Metadata{
+						Name: "node-no-upgrader",
+					},
+				},
+				Spec: types.InstanceSpecV1{
+					Hostname: "no-upgrader.example.com",
+					Version:  "18.3.0",
+					Services: []types.SystemRole{types.RoleNode},
+				},
+			},
 		}
 
 		bots := []*machineidv1.BotInstance{
@@ -1038,7 +1050,7 @@ func TestInventoryCacheFiltering(t *testing.T) {
 		require.Equal(t, "18.1.0", resp.Items[0].GetInstance().Spec.Version)
 
 		// Test predicate query filtering by version (greater than) for both instance types.
-		// This should return 2 instances and 1 bot instance.
+		// This should return 3 instances and 1 bot instance.
 		resp, err = inventoryCache.ListUnifiedInstances(ctx, &inventoryv1.ListUnifiedInstancesRequest{
 			PageSize: 100,
 			Filter: &inventoryv1.ListUnifiedInstancesFilter{
@@ -1047,7 +1059,7 @@ func TestInventoryCacheFiltering(t *testing.T) {
 			},
 		})
 		require.NoError(t, err)
-		require.Len(t, resp.Items, 3)
+		require.Len(t, resp.Items, 4)
 
 		// Test predicate query filtering by version (between)
 		resp, err = inventoryCache.ListUnifiedInstances(ctx, &inventoryv1.ListUnifiedInstancesRequest{
@@ -1058,7 +1070,7 @@ func TestInventoryCacheFiltering(t *testing.T) {
 			},
 		})
 		require.NoError(t, err)
-		require.Len(t, resp.Items, 2)
+		require.Len(t, resp.Items, 3)
 
 		// Test predicate query filtering by hostname
 		resp, err = inventoryCache.ListUnifiedInstances(ctx, &inventoryv1.ListUnifiedInstancesRequest{
@@ -1117,6 +1129,30 @@ func TestInventoryCacheFiltering(t *testing.T) {
 		}
 		require.True(t, upgraders["kube"])
 		require.Len(t, upgraders, 1)
+
+		// Test filtering for no upgrader works
+		resp, err = inventoryCache.ListUnifiedInstances(ctx, &inventoryv1.ListUnifiedInstancesRequest{
+			PageSize: 100,
+			Filter: &inventoryv1.ListUnifiedInstancesFilter{
+				Upgraders:     []string{""},
+				InstanceTypes: []inventoryv1.InstanceType{inventoryv1.InstanceType_INSTANCE_TYPE_INSTANCE},
+			},
+		})
+		require.NoError(t, err)
+		require.Len(t, resp.Items, 1)
+		require.Equal(t, "no-upgrader.example.com", resp.Items[0].GetInstance().Spec.Hostname)
+		require.Empty(t, resp.Items[0].GetInstance().Spec.ExternalUpgrader)
+
+		// Test filtering for no upgrader or kube upgrader
+		resp, err = inventoryCache.ListUnifiedInstances(ctx, &inventoryv1.ListUnifiedInstancesRequest{
+			PageSize: 100,
+			Filter: &inventoryv1.ListUnifiedInstancesFilter{
+				Upgraders:     []string{"", "kube"},
+				InstanceTypes: []inventoryv1.InstanceType{inventoryv1.InstanceType_INSTANCE_TYPE_INSTANCE},
+			},
+		})
+		require.NoError(t, err)
+		require.Len(t, resp.Items, 3) // 2 with kube upgrader + 1 with no upgrader
 	})
 }
 
diff --git a/lib/web/inventory.go b/lib/web/inventory.go
index 1542bb920d6..e2e5d142ea8 100644
--- a/lib/web/inventory.go
+++ b/lib/web/inventory.go
@@ -89,11 +89,18 @@ func (h *Handler) clusterUnifiedInstancesGet(w http.ResponseWriter, r *http.Requ
 		}
 	}
 
+	// We don't use splitQuery for parsing upgraders since it should be possible to filter for upgrader "" (none),
+	// and splitQuery would remove it.
+	var upgraders []string
+	if upgradersParam := values.Get("upgraders"); upgradersParam != "" {
+		upgraders = strings.Split(upgradersParam, ",")
+	}
+
 	filter := &inventoryv1.ListUnifiedInstancesFilter{
 		Search:              values.Get("search"),
 		PredicateExpression: values.Get("query"),
 		Services:            splitQuery(values.Get("services")),
-		Upgraders:           splitQuery(values.Get("upgraders")),
+		Upgraders:           upgraders,
 		UpdaterGroups:       splitQuery(values.Get("updaterGroups")),
 	}
 
diff --git a/web/packages/teleport/src/Instances/Instances.tsx b/web/packages/teleport/src/Instances/Instances.tsx
index 6c1bf3706e2..c33437fe0b3 100644
--- a/web/packages/teleport/src/Instances/Instances.tsx
+++ b/web/packages/teleport/src/Instances/Instances.tsx
@@ -96,7 +96,7 @@ export function Instances() {
 
   const upgradersParam = queryParams.get('upgraders');
   const selectedUpgraders = (
-    upgradersParam ? upgradersParam.split(',') : []
+    upgradersParam !== null ? upgradersParam.split(',') : []
   ) as UpgraderType[];
 
   const versionFilter = queryParams.get('version_filter') || '';