From e50a7f3dbc18bfcd0cd0179bfb65e03fedcc331e Mon Sep 17 00:00:00 2001
From: Michael Aspinwall <maspinwall@google.com>
Date: Mon, 18 May 2026 18:19:58 +0000
Subject: [PATCH] Fix nil check for store metrics

---
 .../src/k8s.io/client-go/tools/cache/store.go   |  3 +++
 .../k8s.io/client-go/tools/cache/store_test.go  | 17 +++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/staging/src/k8s.io/client-go/tools/cache/store.go b/staging/src/k8s.io/client-go/tools/cache/store.go
index 261ed60d9ca..76cb70c5693 100644
--- a/staging/src/k8s.io/client-go/tools/cache/store.go
+++ b/staging/src/k8s.io/client-go/tools/cache/store.go
@@ -402,6 +402,9 @@ func WithTransformer(transformer TransformFunc) StoreOption {
 func WithStoreMetrics(identifier InformerNameAndResource, metrics InformerMetricsProvider) StoreOption {
 	return func(c *cache) {
 		c.identifier = identifier
+		if metrics == nil {
+			metrics = globalInformerMetricsProvider
+		}
 		c.metrics = metrics
 	}
 }
diff --git a/staging/src/k8s.io/client-go/tools/cache/store_test.go b/staging/src/k8s.io/client-go/tools/cache/store_test.go
index f3c018c11ac..7cee3722ed6 100644
--- a/staging/src/k8s.io/client-go/tools/cache/store_test.go
+++ b/staging/src/k8s.io/client-go/tools/cache/store_test.go
@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/util/sets"
 )
 
@@ -246,3 +247,19 @@ func TestCacheTransactionShouldIndexErrors(t *testing.T) {
 		})
 	}
 }
+
+func TestWithStoreMetricsDefaulting(t *testing.T) {
+	name, err := NewInformerName("test-informer")
+	if err != nil {
+		t.Fatalf("failed to create informer name: %v", err)
+	}
+	defer name.Release()
+	gvr := schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "deployments"}
+	id := name.WithResource(gvr)
+
+	s := NewStore(testStoreKeyFunc, WithStoreMetrics(id, nil)).(*cache)
+
+	if s.metrics == nil {
+		t.Errorf("expected c.metrics to be populated, got nil")
+	}
+}