extend CRD map and set validation

staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/validation/validation.go

@@ -64,6 +64,7 @@ func ValidateCustomResourceDefinition(obj *apiextensions.CustomResourceDefinitio
 		requireStructuralSchema:                  requireStructuralSchema(requestGV, nil),
 		requirePrunedDefaults:                    true,
 		requireAtomicSetType:                     true,
+		requireMapListKeysMapSetValidation:       true,
 	}
 
 	allErrs := genericvalidation.ValidateObjectMeta(&obj.ObjectMeta, false, nameValidationFn, field.NewPath("metadata"))
@@ -93,6 +94,10 @@ type validationOptions struct {
 	requirePrunedDefaults bool
 	// requireAtomicSetType indicates that the items type for a x-kubernetes-list-type=set list must be atomic.
 	requireAtomicSetType bool
+	// requireMapListKeysMapSetValidation indicates that:
+	// 1. For x-kubernetes-list-type=map list, key fields are not nullable, and are required or have a default
+	// 2. For x-kubernetes-list-type=map or x-kubernetes-list-type=set list, the whole item must not be nullable.
+	requireMapListKeysMapSetValidation bool
 }
 
 // ValidateCustomResourceDefinitionUpdate statically validates
@@ -106,6 +111,7 @@ func ValidateCustomResourceDefinitionUpdate(obj, oldObj *apiextensions.CustomRes
 		requireStructuralSchema:                  requireStructuralSchema(requestGV, &oldObj.Spec),
 		requirePrunedDefaults:                    requirePrunedDefaults(&oldObj.Spec),
 		requireAtomicSetType:                     requireAtomicSetType(&oldObj.Spec),
+		requireMapListKeysMapSetValidation:       requireMapListKeysMapSetValidation(&oldObj.Spec),
 	}
 
 	allErrs := genericvalidation.ValidateObjectMetaUpdate(&obj.ObjectMeta, &oldObj.ObjectMeta, field.NewPath("metadata"))
@@ -866,6 +872,58 @@ func ValidateCustomResourceDefinitionOpenAPISchema(schema *apiextensions.JSONSch
 		}
 	}
 
+	if opts.requireMapListKeysMapSetValidation {
+		allErrs = append(allErrs, validateMapListKeysMapSet(schema, fldPath)...)
+	}
+
+	return allErrs
+}
+
+func validateMapListKeysMapSet(schema *apiextensions.JSONSchemaProps, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+
+	if schema.Items == nil || schema.Items.Schema == nil {
+		return nil
+	}
+	if schema.XListType == nil {
+		return nil
+	}
+	if *schema.XListType != "set" && *schema.XListType != "map" {
+		return nil
+	}
+
+	// set and map list items cannot be nullable
+	if schema.Items.Schema.Nullable {
+		allErrs = append(allErrs, field.Forbidden(fldPath.Child("items").Child("nullable"), "cannot be nullable when x-kubernetes-list-type is "+*schema.XListType))
+	}
+
+	switch *schema.XListType {
+	case "map":
+		// ensure all map keys are required or have a default
+		isRequired := make(map[string]bool, len(schema.Items.Schema.Required))
+		for _, required := range schema.Items.Schema.Required {
+			isRequired[required] = true
+		}
+
+		for _, k := range schema.XListMapKeys {
+			obj, ok := schema.Items.Schema.Properties[k]
+			if !ok {
+				// we validate that all XListMapKeys are existing properties in ValidateCustomResourceDefinitionOpenAPISchema, so skipping here is ok
+				continue
+			}
+
+			if isRequired[k] == false && obj.Default == nil {
+				allErrs = append(allErrs, field.Required(fldPath.Child("items").Child("properties").Key(k).Child("default"), "this property is in x-kubernetes-list-map-keys, so it must have a default or be a required property"))
+			}
+
+			if obj.Nullable {
+				allErrs = append(allErrs, field.Forbidden(fldPath.Child("items").Child("properties").Key(k).Child("nullable"), "this property is in x-kubernetes-list-map-keys, so it cannot be nullable"))
+			}
+		}
+	case "set":
+		// no other set-specific validation
+	}
+
 	return allErrs
 }
 
@@ -1268,6 +1326,16 @@ func hasNonAtomicSetType(schema *apiextensions.JSONSchemaProps) bool {
 	})
 }
 
+func requireMapListKeysMapSetValidation(oldCRDSpec *apiextensions.CustomResourceDefinitionSpec) bool {
+	return !hasSchemaWith(oldCRDSpec, hasInvalidMapListKeysMapSet)
+}
+
+func hasInvalidMapListKeysMapSet(schema *apiextensions.JSONSchemaProps) bool {
+	return schemaHas(schema, func(schema *apiextensions.JSONSchemaProps) bool {
+		return len(validateMapListKeysMapSet(schema, field.NewPath(""))) > 0
+	})
+}
+
 // requireValidPropertyType returns true if valid openapi v3 types should be required for the given API version
 func requireValidPropertyType(requestGV schema.GroupVersion, oldCRDSpec *apiextensions.CustomResourceDefinitionSpec) bool {
 	if requestGV == apiextensionsv1beta1.SchemeGroupVersion {

staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/validation/validation_test.go

@@ -6004,6 +6004,520 @@ func TestValidateCustomResourceDefinitionUpdate(t *testing.T) {
 				invalid("spec", "preserveUnknownFields"),
 			},
 		},
+		{
+			name: "allow non-required key with no default in list of type map if pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type: "object",
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type: "object",
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: nil,
+		},
+		{
+			name: "reject non-required key with no default in list of type map if not pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type: "object",
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type:    "string",
+												Default: jsonPtr("stuff"),
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type: "object",
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: []validationMatch{
+				required("spec", "validation", "openAPIV3Schema", "properties[bar]", "items", "properties[key]", "default"),
+			},
+		},
+		{
+			name: "allow nullable key in list of type map if pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type:     "string",
+												Nullable: true,
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type:     "string",
+												Nullable: true,
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: nil,
+		},
+		{
+			name: "reject nullable key in list of type map if not pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type:     "string",
+												Nullable: true,
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: []validationMatch{
+				forbidden("spec", "validation", "openAPIV3Schema", "properties[bar]", "items", "properties[key]", "nullable"),
+			},
+		},
+		{
+			name: "allow nullable item in list of type map if pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Nullable: true,
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Nullable: true,
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: nil,
+		},
+		{
+			name: "reject nullable item in list of type map if not pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:         "array",
+								XListType:    strPtr("map"),
+								XListMapKeys: []string{"key"},
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "object",
+										Nullable: true,
+										Required: []string{"key"},
+										Properties: map[string]apiextensions.JSONSchemaProps{
+											"key": {
+												Type: "string",
+											},
+										},
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: []validationMatch{
+				forbidden("spec", "validation", "openAPIV3Schema", "properties[bar]", "items", "nullable"),
+			},
+		},
+		{
+			name: "allow nullable items in list of type set if pre-existing",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:      "array",
+								XListType: strPtr("set"),
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "string",
+										Nullable: true,
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:      "array",
+								XListType: strPtr("set"),
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "string",
+										Nullable: true,
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: nil,
+		},
+		{
+			name: "reject nullable items in list of type set if not pre-exisiting",
+			old: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"foo": {
+								Type:      "array",
+								XListType: strPtr("set"),
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type: "string",
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			resource: &apiextensions.CustomResourceDefinition{
+				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "1"},
+				Spec: apiextensions.CustomResourceDefinitionSpec{
+					Group:    "group.com",
+					Scope:    apiextensions.ResourceScope("Cluster"),
+					Names:    apiextensions.CustomResourceDefinitionNames{Plural: "plural", Singular: "singular", Kind: "Plural", ListKind: "PluralList"},
+					Versions: []apiextensions.CustomResourceDefinitionVersion{{Name: "version", Served: true, Storage: true}},
+					Validation: &apiextensions.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{"bar": {
+								Type:      "array",
+								XListType: strPtr("set"),
+								Items: &apiextensions.JSONSchemaPropsOrArray{
+									Schema: &apiextensions.JSONSchemaProps{
+										Type:     "string",
+										Nullable: true,
+									},
+								},
+							}},
+						},
+					},
+				},
+				Status: apiextensions.CustomResourceDefinitionStatus{StoredVersions: []string{"version"}},
+			},
+			errors: []validationMatch{
+				forbidden("spec", "validation", "openAPIV3Schema", "properties[bar]", "items", "nullable"),
+			},
+		},
 	}
 
 	for _, tc := range tests {
@@ -6632,6 +7146,202 @@ func TestValidateCustomResourceDefinitionValidation(t *testing.T) {
 			},
 			wantError: false,
 		},
+		{
+			name: "invalid map with non-required key and no default",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:         "array",
+					XListType:    strPtr("map"),
+					XListMapKeys: []string{"key"},
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{
+								"key": {
+									Type: "string",
+								},
+							},
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: true,
+		},
+		{
+			name: "allowed map with required key and no default",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:         "array",
+					XListType:    strPtr("map"),
+					XListMapKeys: []string{"key"},
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Type:     "object",
+							Required: []string{"key"},
+							Properties: map[string]apiextensions.JSONSchemaProps{
+								"key": {
+									Type: "string",
+								},
+							},
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: false,
+		},
+		{
+			name: "allowed map with non-required key and default",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:         "array",
+					XListType:    strPtr("map"),
+					XListMapKeys: []string{"key"},
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{
+								"key": {
+									Type:    "string",
+									Default: jsonPtr("stuff"),
+								},
+							},
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				allowDefaults:                      true,
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: false,
+		},
+		{
+			name: "invalid map with nullable key",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:         "array",
+					XListType:    strPtr("map"),
+					XListMapKeys: []string{"key"},
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Type: "object",
+							Properties: map[string]apiextensions.JSONSchemaProps{
+								"key": {
+									Type:     "string",
+									Nullable: true,
+								},
+							},
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: true,
+		},
+		{
+			name: "invalid map with nullable items",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:         "array",
+					XListType:    strPtr("map"),
+					XListMapKeys: []string{"key"},
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Type:     "object",
+							Nullable: true,
+							Properties: map[string]apiextensions.JSONSchemaProps{
+								"key": {
+									Type: "string",
+								},
+							},
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: true,
+		},
+		{
+			name: "valid map with some required, some defaulted, and non-key fields",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:         "array",
+					XListType:    strPtr("map"),
+					XListMapKeys: []string{"a"},
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Type:     "object",
+							Required: []string{"a", "c"},
+							Properties: map[string]apiextensions.JSONSchemaProps{
+								"key": {
+									Type: "string",
+								},
+								"a": {
+									Type: "string",
+								},
+								"b": {
+									Type:    "string",
+									Default: jsonPtr("stuff"),
+								},
+								"c": {
+									Type: "int",
+								},
+							},
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: true,
+		},
+		{
+			name: "invalid set with nullable items",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:      "array",
+					XListType: strPtr("set"),
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Nullable: true,
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: true,
+		},
+		{
+			name: "allowed set with non-nullable items",
+			input: apiextensions.CustomResourceValidation{
+				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
+					Type:      "array",
+					XListType: strPtr("set"),
+					Items: &apiextensions.JSONSchemaPropsOrArray{
+						Schema: &apiextensions.JSONSchemaProps{
+							Nullable: false,
+						},
+					},
+				},
+			},
+			opts: validationOptions{
+				requireMapListKeysMapSetValidation: true,
+			},
+			wantError: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

staging/src/k8s.io/apiextensions-apiserver/test/integration/listtype_test.go

@@ -67,6 +67,7 @@ properties:
     x-kubernetes-list-map-keys: ["a", "b"]
     items:
       type: object
+      required: ["a", "b"]
       properties:
         a:
           type: integer
@@ -86,6 +87,7 @@ properties:
     x-kubernetes-list-map-keys: ["a", "b"]
     items:
       type: object
+      required: ["a", "b"]
       properties:
         a:
           type: integer
@@ -106,9 +108,9 @@ kind: Foo
 apiVersion: tests.example.com/v1beta1
 metadata:
   name: foo
-correct-map: [{"a":1,"b":1,c:"1"},{"a":1,"b":2,c:"2"},{"a":1,c:"3"}]
+correct-map: [{"a":1,"b":1,c:"1"},{"a":1,"b":2,c:"2"},{"a":1,"b":3,c:"3"}]
 correct-set: [{"a":1,"b":1},{"a":1,"b":2},{"a":1},{"a":1,"b":4}]
-invalid-map: [{"a":1,"b":1,c:"1"},{"a":1,"b":2,c:"2"},{"a":1,c:"3"},{"a":1,"b":1,c:"4"}]
+invalid-map: [{"a":1,"b":1,c:"1"},{"a":1,"b":2,c:"2"},{"a":1,"b":3,c:"3"},{"a":1,"b":1,c:"4"}]
 invalid-set: [{"a":1,"b":1},{"a":1,"b":2},{"a":1},{"a":1,"b":4},{"a":1,"b":1}]
 `
 )

test/integration/apiserver/apply/apply_crd_test.go

@@ -191,12 +191,12 @@ func TestApplyCRDStructuralSchema(t *testing.T) {
 										"type": "string"
 									},
 									"protocol": {
-										"type": "string",
-										"nullable": true
+										"type": "string"
 									}
 								},
 								"required": [
-									"containerPort"
+									"containerPort",
+									"protocol"
 								],
 								"type": "object"
 							}