kubernetes/staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/defaulting/algorithm.go

// isNonNullalbeNull returns true if the item is nil AND it's nullable
func isNonNullableNull(x interface{ … }

// Default does defaulting of x depending on default values in s.
// Default values from s are deep-copied.
//
// PruneNonNullableNullsWithoutDefaults has left the non-nullable nulls
// that have a default here.
func Default(x interface{ … }