apierrors: Avoid spurious <nil> in invalid error message

staging/src/k8s.io/apimachinery/pkg/api/errors/errors.go

@@ -289,7 +289,7 @@ func NewInvalid(qualifiedKind schema.GroupKind, name string, errs field.ErrorLis
 			Field:   err.Field,
 		})
 	}
-	return &StatusError{metav1.Status{
+	err := &StatusError{metav1.Status{
 		Status: metav1.StatusFailure,
 		Code:   http.StatusUnprocessableEntity,
 		Reason: metav1.StatusReasonInvalid,
@@ -299,8 +299,14 @@ func NewInvalid(qualifiedKind schema.GroupKind, name string, errs field.ErrorLis
 			Name:   name,
 			Causes: causes,
 		},
-		Message: fmt.Sprintf("%s %q is invalid: %v", qualifiedKind.String(), name, errs.ToAggregate()),
 	}}
+	aggregatedErrs := errs.ToAggregate()
+	if aggregatedErrs == nil {
+		err.ErrStatus.Message = fmt.Sprintf("%s %q is invalid", qualifiedKind.String(), name)
+	} else {
+		err.ErrStatus.Message = fmt.Sprintf("%s %q is invalid: %v", qualifiedKind.String(), name, aggregatedErrs)
+	}
+	return err
 }
 
 // NewBadRequest creates an error that indicates that the request is invalid and can not be processed.

staging/src/k8s.io/apimachinery/pkg/api/errors/errors_test.go

@@ -125,6 +125,7 @@ func TestNewInvalid(t *testing.T) {
 	testCases := []struct {
 		Err     *field.Error
 		Details *metav1.StatusDetails
+		Msg     string
 	}{
 		{
 			field.Duplicate(field.NewPath("field[0].name"), "bar"),
@@ -136,6 +137,7 @@ func TestNewInvalid(t *testing.T) {
 					Field: "field[0].name",
 				}},
 			},
+			`Kind "name" is invalid: field[0].name: Duplicate value: "bar"`,
 		},
 		{
 			field.Invalid(field.NewPath("field[0].name"), "bar", "detail"),
@@ -147,6 +149,7 @@ func TestNewInvalid(t *testing.T) {
 					Field: "field[0].name",
 				}},
 			},
+			`Kind "name" is invalid: field[0].name: Invalid value: "bar": detail`,
 		},
 		{
 			field.NotFound(field.NewPath("field[0].name"), "bar"),
@@ -158,6 +161,7 @@ func TestNewInvalid(t *testing.T) {
 					Field: "field[0].name",
 				}},
 			},
+			`Kind "name" is invalid: field[0].name: Not found: "bar"`,
 		},
 		{
 			field.NotSupported(field.NewPath("field[0].name"), "bar", nil),
@@ -169,6 +173,7 @@ func TestNewInvalid(t *testing.T) {
 					Field: "field[0].name",
 				}},
 			},
+			`Kind "name" is invalid: field[0].name: Unsupported value: "bar"`,
 		},
 		{
 			field.Required(field.NewPath("field[0].name"), ""),
@@ -180,12 +185,28 @@ func TestNewInvalid(t *testing.T) {
 					Field: "field[0].name",
 				}},
 			},
+			`Kind "name" is invalid: field[0].name: Required value`,
+		},
+		{
+			nil,
+			&metav1.StatusDetails{
+				Kind:   "Kind",
+				Name:   "name",
+				Causes: []metav1.StatusCause{},
+			},
+			`Kind "name" is invalid`,
 		},
 	}
 	for i, testCase := range testCases {
 		vErr, expected := testCase.Err, testCase.Details
-		expected.Causes[0].Message = vErr.ErrorBody()
+		if vErr != nil && expected != nil {
-		err := NewInvalid(kind("Kind"), "name", field.ErrorList{vErr})
+			expected.Causes[0].Message = vErr.ErrorBody()
+		}
+		var errList field.ErrorList
+		if vErr != nil {
+			errList = append(errList, vErr)
+		}
+		err := NewInvalid(kind("Kind"), "name", errList)
 		status := err.ErrStatus
 		if status.Code != 422 || status.Reason != metav1.StatusReasonInvalid {
 			t.Errorf("%d: unexpected status: %#v", i, status)
@@ -193,6 +214,9 @@ func TestNewInvalid(t *testing.T) {
 		if !reflect.DeepEqual(expected, status.Details) {
 			t.Errorf("%d: expected %#v, got %#v", i, expected, status.Details)
 		}
+		if testCase.Msg != status.Message {
+			t.Errorf("%d: expected\n%s\ngot\n%s", i, testCase.Msg, status.Message)
+		}
 	}
 }