kubernetes/staging/src/k8s.io/apimachinery/pkg/util/jsonmergepatch/patch.go

// Create a 3-way merge patch based-on JSON merge patch.
// Calculate addition-and-change patch between current and modified.
// Calculate deletion patch between original and modified.
func CreateThreeWayJSONMergePatch(original, modified, current []byte, fns ...mergepatch.PreconditionFunc) ([]byte, error) { … }

// keepOrDeleteNullInJsonPatch takes a json-encoded byte array and a boolean.
// It returns a filtered object and its corresponding json-encoded byte array.
// It is a wrapper of func keepOrDeleteNullInObj
func keepOrDeleteNullInJsonPatch(patch []byte, keepNull bool) ([]byte, map[string]interface{ … }

// keepOrDeleteNullInObj will keep only the null value and delete all the others,
// if keepNull is true. Otherwise, it will delete all the null value and keep the others.
func keepOrDeleteNullInObj(m map[string]interface{ … }

func meetPreconditions(patchObj map[string]interface{ … }