fix(action): prevent nil pointer dereference in installCRDs

Signed-off-by: shenpeng.sp0916 <shenpeng.sp0916@bytedance.com>

Backport the fix from #31578 to dev-v3 branch.

The installCRDs function previously could panic in several scenarios:
- When a CRD object has a nil File field (accessing obj.File.Data)
- When a CRD object has nil File.Data (passing nil to KubeClient.Build)
- When KubeClient.Build returns an empty resource list (accessing res[0])
- When RESTClientGetter is nil (calling ToDiscoveryClient/ToRESTMapper)

Added nil and empty checks to return descriptive errors instead of
panicking in all these cases.

Closes #31552

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: shenpeng.sp0916 <shenpeng.sp0916@bytedance.com>

pkg/action/install.go

@@ -162,12 +162,24 @@ func (i *Install) installCRDs(crds []chart.CRD) error {
 	// We do these one file at a time in the order they were read.
 	totalItems := []*resource.Info{}
 	for _, obj := range crds {
+		if obj.File == nil {
+			return fmt.Errorf("failed to install CRD %s: file is empty", obj.Name)
+		}
+
+		if obj.File.Data == nil {
+			return fmt.Errorf("failed to install CRD %s: file data is empty", obj.Name)
+		}
+
 		// Read in the resources
 		res, err := i.cfg.KubeClient.Build(bytes.NewBuffer(obj.File.Data), false)
 		if err != nil {
 			return errors.Wrapf(err, "failed to install CRD %s", obj.Name)
 		}
 
+		if len(res) == 0 {
+			return fmt.Errorf("failed to install CRD %s: no Kubernetes resources parsed from CRD data", obj.Name)
+		}
+
 		// Send them to Kube
 		if _, err := i.cfg.KubeClient.Create(res); err != nil {
 			// If the error is CRD already exists, continue.
@@ -191,27 +203,29 @@ func (i *Install) installCRDs(crds []chart.CRD) error {
 		// the case when an action configuration is reused for multiple actions,
 		// as otherwise it is later loaded by ourselves when getCapabilities
 		// is called later on in the installation process.
-		if i.cfg.Capabilities != nil {
-			discoveryClient, err := i.cfg.RESTClientGetter.ToDiscoveryClient()
-			if err != nil {
-				return err
-			}
+		if i.cfg.RESTClientGetter != nil {
+			if i.cfg.Capabilities != nil {
+				discoveryClient, err := i.cfg.RESTClientGetter.ToDiscoveryClient()
+				if err != nil {
+					return err
+				}
 
-			i.cfg.Log("Clearing discovery cache")
-			discoveryClient.Invalidate()
+				i.cfg.Log("Clearing discovery cache")
+				discoveryClient.Invalidate()
 
-			_, _ = discoveryClient.ServerGroups()
-		}
+				_, _ = discoveryClient.ServerGroups()
+			}
 
-		// Invalidate the REST mapper, since it will not have the new CRDs
-		// present.
-		restMapper, err := i.cfg.RESTClientGetter.ToRESTMapper()
-		if err != nil {
-			return err
-		}
-		if resettable, ok := restMapper.(meta.ResettableRESTMapper); ok {
-			i.cfg.Log("Clearing REST mapper cache")
-			resettable.Reset()
+			// Invalidate the REST mapper, since it will not have the new CRDs
+			// present.
+			restMapper, err := i.cfg.RESTClientGetter.ToRESTMapper()
+			if err != nil {
+				return err
+			}
+			if resettable, ok := restMapper.(meta.ResettableRESTMapper); ok {
+				i.cfg.Log("Clearing REST mapper cache")
+				resettable.Reset()
+			}
 		}
 	}
 	return nil

pkg/action/install_test.go

@@ -923,3 +923,42 @@ func TestInstallWithSystemLabels(t *testing.T) {
 
 	is.Equal(fmt.Errorf("user supplied labels contains system reserved label name. System labels: %+v", driver.GetSystemLabels()), err)
 }
+
+func TestInstallCRDs_CheckNilErrors(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []chart.CRD
+	}{
+		{
+			name: "only one crd with file nil",
+			input: []chart.CRD{
+				{Name: "one", File: nil},
+			},
+		},
+		{
+			name: "only one crd with its file data nil",
+			input: []chart.CRD{
+				{Name: "one", File: &chart.File{Name: "crds/foo.yaml", Data: nil}},
+			},
+		},
+		{
+			name: "at least a crd with its file data nil",
+			input: []chart.CRD{
+				{Name: "one", File: &chart.File{Name: "crds/foo.yaml", Data: []byte("data")}},
+				{Name: "two", File: &chart.File{Name: "crds/foo2.yaml", Data: nil}},
+				{Name: "three", File: &chart.File{Name: "crds/foo3.yaml", Data: []byte("data")}},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			instAction := installAction(t)
+
+			err := instAction.installCRDs(tt.input)
+			if err == nil {
+				t.Errorf("got nil expected err")
+			}
+		})
+	}
+}