fix: Add nil check for getOCIClientCertFromSecret (#466)

Author: joekr

cloud/util/util.go

@@ -78,7 +78,7 @@ func GetClusterIdentityFromRef(ctx context.Context, c client.Client, ociClusterN
 // getOCIClientCertFromSecret returns the cert referenced by the OCICluster.
 func getOCIClientCertFromSecret(ctx context.Context, c client.Client, ociClusterNamespace string, overrides *infrastructurev1beta2.ClientOverrides) (*corev1.Secret, error) {
 	secret := &corev1.Secret{}
-	if overrides != nil {
+	if overrides != nil && overrides.CertOverride != nil {
 		certSecretRef := overrides.CertOverride
 		namespace := certSecretRef.Namespace
 		if namespace == "" {

cloud/util/util_test.go

@@ -879,3 +879,40 @@ func TestDeleteManagedMachinesIfNotExists(t *testing.T) {
 		})
 	}
 }
+
+func TestGetOCIClientCertFromSecret(t *testing.T) {
+	testCases := []struct {
+		name          string
+		overrides     *infrastructurev1beta2.ClientOverrides
+		objects       []client.Object
+		errorExpected bool
+		errorMessage  string
+	}{
+		{
+			name: "NPE case - nil CertOverride",
+			overrides: &infrastructurev1beta2.ClientOverrides{
+				CertOverride: nil, // This should cause NPE
+			},
+			objects:       []client.Object{},
+			errorExpected: true, // Should panic or return error
+		},
+		// Add more test cases...
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.name, func(t *testing.T) {
+			g := NewWithT(t)
+			client := fake.NewClientBuilder().WithObjects(tt.objects...).Build()
+
+			// This should either panic or return an error
+			_, err := getOCIClientCertFromSecret(context.Background(), client, "default", tt.overrides)
+
+			if tt.errorExpected {
+				// Currently this will panic, but after the fix it should return an error
+				g.Expect(err).To(Not(BeNil()))
+			} else {
+				g.Expect(err).To(BeNil())
+			}
+		})
+	}
+}