generated: ./hack/update-codegen.sh && ./hack/update-openapi-spec.sh

pkg/generated/openapi/zz_generated.openapi.go

@@ -2498,6 +2498,13 @@ func schema_k8sio_api_admissionregistration_v1alpha1_Validation(ref common.Refer
 							Format:      "",
 						},
 					},
+					"messageExpression": {
+						SchemaProps: spec.SchemaProps{
+							Description: "messageExpression declares a CEL expression that evaluates to the validation failure message that is returned when this rule fails. Since messageExpression is used as a failure message, it must evaluate to a string. If both message and messageExpression are present on a validation, then messageExpression will be used if validation fails. If messageExpression results in a runtime error, the runtime error is logged, and the validation failure message is produced as if the messageExpression field were unset. If messageExpression evaluates to an empty string, a string with only spaces, or a string that contains line breaks, then the validation failure message will also be produced as if the messageExpression field were unset, and the fact that messageExpression produced an empty string/string with only spaces/string with line breaks will be logged. messageExpression has access to all the same variables as the `expression` except for 'authorizer' and 'authorizer.requestResource'. Example: \"object.x must be less than max (\"+string(params.max)+\")\"",
+							Type:        []string{"string"},
+							Format:      "",
+						},
+					},
 				},
 				Required: []string{"expression"},
 			},