kubernetes/staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/listtype/validation.go

// ValidateListSetsAndMaps validates that arrays with x-kubernetes-list-type "map" and "set" fulfill the uniqueness
// invariants for the keys (maps) and whole elements (sets).
func ValidateListSetsAndMaps(fldPath *field.Path, s *schema.Structural, obj map[string]interface{ … }

func validationListSetAndMaps(fldPath *field.Path, s *schema.Structural, obj interface{ … }

func validateListSetsAndMapsArray(fldPath *field.Path, s *schema.Structural, obj []interface{ … }

// validateListSet validated uniqueness of unstructured objects (scalar and compound) and
// returns the first non-unique appearance of items.
//
// As a special case to distinguish undefined key and null values, we allow unspecifiedKeyValue and nullObjectValue
// which are both handled like scalars with correct comparison by Golang.
func validateListSet(fldPath *field.Path, obj []interface{ … }

func validateListMap(fldPath *field.Path, s *schema.Structural, obj []interface{ … }