Add FieldPath and Reason to XValidation marker

pkg/crd/markers/validation.go

@@ -312,6 +312,8 @@ type XValidation struct {
 	Rule              string
 	Message           string `marker:",optional"`
 	MessageExpression string `marker:"messageExpression,optional"`
+	Reason            string `marker:"reason,optional"`
+	FieldPath         string `marker:"fieldPath,optional"`
 }
 
 func (m Maximum) ApplyToSchema(schema *apiext.JSONSchemaProps) error {
@@ -534,10 +536,22 @@ func (m XIntOrString) ApplyPriority() ApplyPriority {
 }
 
 func (m XValidation) ApplyToSchema(schema *apiext.JSONSchemaProps) error {
+	var reason *apiext.FieldValueErrorReason
+	if m.Reason != "" {
+		switch m.Reason {
+		case string(apiext.FieldValueRequired), string(apiext.FieldValueInvalid), string(apiext.FieldValueForbidden), string(apiext.FieldValueDuplicate):
+			reason = (*apiext.FieldValueErrorReason)(&m.Reason)
+		default:
+			return fmt.Errorf("invalid reason %s, valid values are %s, %s, %s and %s", m.Reason, apiext.FieldValueRequired, apiext.FieldValueInvalid, apiext.FieldValueForbidden, apiext.FieldValueDuplicate)
+		}
+	}
+
 	schema.XValidations = append(schema.XValidations, apiext.ValidationRule{
 		Rule:              m.Rule,
 		Message:           m.Message,
 		MessageExpression: m.MessageExpression,
+		Reason:            reason,
+		FieldPath:         m.FieldPath,
 	})
 	return nil
 }

pkg/crd/testdata/cronjob_types.go

@@ -39,6 +39,7 @@ import (
 // NOTE: json tags are required.  Any new fields you add must have json tags for the fields to be serialized.
 
 // CronJobSpec defines the desired state of CronJob
+// +kubebuilder:validation:XValidation:rule="has(oldSelf.forbiddenInt) || !has(self.forbiddenInt)",message="forbiddenInt is not allowed",fieldPath=".forbiddenInt",reason="FieldValueForbidden"
 type CronJobSpec struct {
 	// The schedule in Cron format, see https://en.wikipedia.org/wiki/Cron.
 	Schedule string `json:"schedule"`
@@ -251,6 +252,10 @@ type CronJobSpec struct {
 	// +kubebuilder:validation:XValidation:rule="self.size() % 2 == 0",messageExpression="'Length has to be even but is ' + len(self.stringWithEvenLengthAndMessageExpression) + ' instead'"
 	StringWithEvenLengthAndMessageExpression string `json:"stringWithEvenLengthAndMessageExpression,omitempty"`
 
+	// Test that we can add a forbidden field using XValidation Reason and FieldPath.
+	// The validation is applied to the spec struct itself and not the field.
+	ForbiddenInt int `json:"forbiddenInt,omitempty"`
+
 	// Checks that fixed-length arrays work
 	Array [3]int `json:"array,omitempty"`
 

pkg/crd/testdata/testdata.kubebuilder.io_cronjobs.yaml

@@ -196,6 +196,11 @@ spec:
                 description: This tests that exported fields are not skipped in the
                   schema generation
                 type: string
+              forbiddenInt:
+                description: |-
+                  Test that we can add a forbidden field using XValidation Reason and FieldPath.
+                  The validation is applied to the spec struct itself and not the field.
+                type: integer
               hosts:
                 description: This tests string slice item validation.
                 items:
@@ -6806,11 +6811,12 @@ spec:
                   rule: self.size() % 2 == 0
                 - rule: "true"
               stringWithEvenLengthAndMessageExpression:
-                description: Test of the expression-based validation with
-                  messageExpression marker.
+                description: Test of the expression-based validation with messageExpression
+                  marker.
                 type: string
                 x-kubernetes-validations:
-                - messageExpression: "'Length has to be even but is ' + len(self.stringWithEvenLengthAndMessageExpression) + ' instead'"
+                - messageExpression: '''Length has to be even but is '' + len(self.stringWithEvenLengthAndMessageExpression)
+                    + '' instead'''
                   rule: self.size() % 2 == 0
               structWithSeveralFields:
                 description: A struct that can only be entirely replaced
@@ -6903,6 +6909,11 @@ spec:
             - unprunedFomTypeAndField
             - unprunedJSON
             type: object
+            x-kubernetes-validations:
+            - fieldPath: .forbiddenInt
+              message: forbiddenInt is not allowed
+              reason: FieldValueForbidden
+              rule: has(oldSelf.forbiddenInt) || !has(self.forbiddenInt)
           status:
             description: CronJobStatus defines the observed state of CronJob
             properties: