From f1cb630bb8dc858d6cc8e21d689f2e77db8ae889 Mon Sep 17 00:00:00 2001
From: Harvey Xia <harvey.xia@reddit.com>
Date: Thu, 19 Jan 2023 09:30:34 -0500
Subject: [PATCH] add support for oneOf

---
 pkg/crd/markers/validation.go |  3 +++
 pkg/crd/schema.go             | 20 ++++++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/pkg/crd/markers/validation.go b/pkg/crd/markers/validation.go
index 5d1496189..d1e61516d 100644
--- a/pkg/crd/markers/validation.go
+++ b/pkg/crd/markers/validation.go
@@ -80,6 +80,9 @@ var FieldOnlyMarkers = []*definitionWithHelp{
 	must(markers.MakeDefinition("optional", markers.DescribesField, struct{}{})).
 		WithHelp(markers.SimpleHelp("CRD validation", "specifies that this field is optional, if fields are required by default.")),
 
+	must(markers.MakeDefinition("kubebuilder:validation:OneOf", markers.DescribesField, struct{}{})).
+		WithHelp(markers.SimpleHelp("CRD validation", "specifies that this field is part of a oneOf group")),
+
 	must(markers.MakeDefinition("nullable", markers.DescribesField, Nullable{})).
 		WithHelp(Nullable{}.Help()),
 
diff --git a/pkg/crd/schema.go b/pkg/crd/schema.go
index e76d3ea88..c4470d3cf 100644
--- a/pkg/crd/schema.go
+++ b/pkg/crd/schema.go
@@ -378,22 +378,34 @@ func structToSchema(ctx *schemaContext, structType *ast.StructType) *apiext.JSON
 			defaultMode = "optional"
 		}
 
+		fieldMarkedOptional := (field.Markers.Get("kubebuilder:validation:Optional") != nil || field.Markers.Get("optional") != nil)
+		fieldMarkedRequired := (field.Markers.Get("kubebuilder:validation:Required") != nil)
+		fieldMarkedOneOf := (field.Markers.Get("kubebuilder:validation:OneOf") != nil)
+
 		switch defaultMode {
 		// if this package isn't set to optional default...
 		case "required":
-			// ...everything that's not inline, omitempty, or explicitly optional is required
-			if !inline && !omitEmpty && field.Markers.Get("kubebuilder:validation:Optional") == nil && field.Markers.Get("optional") == nil {
+			// ...everything that's not inline, not omitempty, not part of a oneOf group, and not explicitly optional is required
+			if !inline && !omitEmpty && !fieldMarkedOneOf && !fieldMarkedOptional {
 				props.Required = append(props.Required, fieldName)
 			}
 
 		// if this package isn't set to required default...
 		case "optional":
-			// ...everything that isn't explicitly required is optional
-			if field.Markers.Get("kubebuilder:validation:Required") != nil {
+			// ...everything that's part of a oneOf group, or not explicitly required is optional
+			if !fieldMarkedOneOf && fieldMarkedRequired {
 				props.Required = append(props.Required, fieldName)
 			}
 		}
 
+		// process oneOf groups
+		if field.Markers.Get("kubebuilder:validation:OneOf") != nil {
+			props.OneOf = append(props.OneOf, apiext.JSONSchemaProps{
+				Properties: map[string]apiext.JSONSchemaProps{fieldName: {}},
+				Required:   []string{fieldName},
+			})
+		}
+
 		var propSchema *apiext.JSONSchemaProps
 		if field.Markers.Get(crdmarkers.SchemalessName) != nil {
 			propSchema = &apiext.JSONSchemaProps{}