fix: handle invalid cache in IsNamespaced by resetting mapper

Author: matteogastaldello

internal/tools/dynamic/dynamic.go

@@ -38,7 +38,15 @@ func IsNamespaced(mapper meta.RESTMapper, gvk schema.GroupVersionKind) (bool, er
 	}
 	mapping, err := mapper.RESTMapping(gvk.GroupKind(), gvk.Version)
 	if err != nil {
-		return false, err
+		if dm, ok := mapper.(interface{ Reset() }); ok {
+			dm.Reset()
+			mapping, err = mapper.RESTMapping(gvk.GroupKind(), gvk.Version)
+			if err != nil {
+				return false, err
+			}
+		} else {
+			return false, err
+		}
 	}
 
 	if mapping.Scope.Name() == meta.RESTScopeNameRoot {

internal/tools/dynamic/dynamic_test.go

@@ -1,6 +1,7 @@
 package dynamic
 
 import (
+	"fmt"
 	"testing"
 
 	"k8s.io/apimachinery/pkg/api/meta"
@@ -193,6 +194,50 @@ func TestIsNamespaced_WithMockMapper(t *testing.T) {
 	}
 }
 
+type MockResettableMapper struct {
+	*MockRESTMapper
+	resetCalled bool
+	failFirst   bool
+}
+
+func (m *MockResettableMapper) Reset() {
+	m.resetCalled = true
+	m.err = nil
+}
+
+func (m *MockResettableMapper) RESTMapping(gk schema.GroupKind, versions ...string) (*meta.RESTMapping, error) {
+	if m.failFirst && !m.resetCalled {
+		return nil, fmt.Errorf("no matches for kind")
+	}
+	return m.MockRESTMapper.RESTMapping(gk, versions...)
+}
+
+func TestIsNamespaced_WithCacheReset(t *testing.T) {
+	gvk := schema.GroupVersionKind{
+		Group:   "example.com",
+		Version: "v1",
+		Kind:    "Example",
+	}
+
+	mock := &MockResettableMapper{
+		MockRESTMapper: &MockRESTMapper{
+			scopeName: meta.RESTScopeNameNamespace,
+		},
+		failFirst: true,
+	}
+
+	got, err := IsNamespaced(mock, gvk)
+	if err != nil {
+		t.Errorf("IsNamespaced() unexpected error after reset = %v", err)
+	}
+	if got != true {
+		t.Errorf("IsNamespaced() = %v, want %v", got, true)
+	}
+	if !mock.resetCalled {
+		t.Error("IsNamespaced() did not call Reset() on mapper")
+	}
+}
+
 func TestIsNamespaced_EdgeCases(t *testing.T) {
 	t.Run("empty GVK", func(t *testing.T) {
 		mockMapper := &MockRESTMapper{