Add comments

Author: jennybuckley

merge/update.go

@@ -181,6 +181,10 @@ func shallowCopyManagers(managers fieldpath.ManagedFields) fieldpath.ManagedFiel
 	return newManagers
 }
 
+// prune will remove a list or map item, iff:
+// * applyingManager applied it last time
+// * applyingManager didn't apply it this time
+// * no other applier claims to manage it
 func (s *Updater) prune(merged typed.TypedValue, managers fieldpath.ManagedFields, applyingManager string, lastSet *fieldpath.VersionedSet) (typed.TypedValue, error) {
 	if lastSet == nil || lastSet.Set.Empty() {
 		return merged, nil
@@ -204,6 +208,8 @@ func (s *Updater) prune(merged typed.TypedValue, managers fieldpath.ManagedField
 	return s.Converter.Convert(pruned, managers[applyingManager].APIVersion)
 }
 
+// addBackOwnedItems adds back any list and map items that were removed by prune,
+// but other appliers (or the current applier's new config) claim to own.
 func (s *Updater) addBackOwnedItems(merged, pruned typed.TypedValue, managedFields fieldpath.ManagedFields, applyingManager string) (typed.TypedValue, error) {
 	var err error
 	managedAtVersion := map[fieldpath.APIVersion]*fieldpath.Set{}
@@ -243,6 +249,10 @@ func (s *Updater) addBackOwnedItems(merged, pruned typed.TypedValue, managedFiel
 	return pruned, nil
 }
 
+
+// addBackDanglingItems makes sure that the only items removed by prune are items that were
+// previously owned by the currently applying manager. This will add back unowned items and items
+// which are owned by Updaters that shouldn't be removed.
 func (s *Updater) addBackDanglingItems(merged, pruned typed.TypedValue, lastSet *fieldpath.VersionedSet) (typed.TypedValue, error) {
 	convertedPruned, err := s.Converter.Convert(pruned, lastSet.APIVersion)
 	if err != nil {