tolerate more than one gvklist item

Some third-party resources could be part of more than one api group.
Allow this to be the case when adding openapi models to openapi data.

pkg/kubectl/cmd/util/openapi/openapi.go

@@ -56,11 +56,13 @@ func NewOpenAPIData(doc *openapi_v2.Document) (Resources, error) {
 		if model == nil {
 			panic("ListModels returns a model that can't be looked-up.")
 		}
-		gvk := parseGroupVersionKind(model)
+		gvkList := parseGroupVersionKind(model)
+		for _, gvk := range gvkList {
 			if len(gvk.Kind) > 0 {
 				resources[gvk] = modelName
 			}
 		}
+	}
 
 	return &document{
 		resources: resources,
@@ -77,48 +79,49 @@ func (d *document) LookupResource(gvk schema.GroupVersionKind) proto.Schema {
 }
 
 // Get and parse GroupVersionKind from the extension. Returns empty if it doesn't have one.
-func parseGroupVersionKind(s proto.Schema) schema.GroupVersionKind {
+func parseGroupVersionKind(s proto.Schema) []schema.GroupVersionKind {
 	extensions := s.GetExtensions()
 
+	gvkListResult := []schema.GroupVersionKind{}
+
 	// Get the extensions
 	gvkExtension, ok := extensions[groupVersionKindExtensionKey]
 	if !ok {
-		return schema.GroupVersionKind{}
+		return []schema.GroupVersionKind{}
 	}
 
-	// gvk extension must be a list of 1 element.
+	// gvk extension must be a list of at least 1 element.
 	gvkList, ok := gvkExtension.([]interface{})
 	if !ok {
-		return schema.GroupVersionKind{}
+		return []schema.GroupVersionKind{}
 	}
-	if len(gvkList) != 1 {
-		return schema.GroupVersionKind{}
-
-	}
-	gvk := gvkList[0]
 
+	for _, gvk := range gvkList {
 		// gvk extension list must be a map with group, version, and
 		// kind fields
 		gvkMap, ok := gvk.(map[interface{}]interface{})
 		if !ok {
-		return schema.GroupVersionKind{}
+			continue
 		}
 		group, ok := gvkMap["group"].(string)
 		if !ok {
-		return schema.GroupVersionKind{}
+			continue
 		}
 		version, ok := gvkMap["version"].(string)
 		if !ok {
-		return schema.GroupVersionKind{}
+			continue
 		}
 		kind, ok := gvkMap["kind"].(string)
 		if !ok {
-		return schema.GroupVersionKind{}
+			continue
 		}
 
-	return schema.GroupVersionKind{
+		gvkListResult = append(gvkListResult, schema.GroupVersionKind{
 			Group:   group,
 			Version: version,
 			Kind:    kind,
+		})
 	}
+
+	return gvkListResult
 }