Remove unused overlay value snapshots

override.go

@@ -407,14 +407,12 @@ func applyPreparedOverride(result *composedDocument, override preparedOverride)
 
 		previous := cloneOrigin(result.origins[path.String()])
 		var displaced []displacedDefinition
-		var before *document.Node
 		if position < 0 {
 			incoming := document.Clone(override.value)
 			current.Mapping = append(current.Mapping, document.Entry{Key: segment.key, KeyLocation: location, ValueLocation: location, Value: incoming})
 			collectOverlayOrigins(result.origins, incoming, path, LayerCLI)
 		} else {
 			existing := current.Mapping[position].Value
-			before = document.Clone(existing)
 			displaced = affectedOverrideOrigins(existing, override.value, result.origins, path)
 			if existing.Kind == document.Mapping && override.value.Kind == document.Mapping {
 				mergeOverlayOrigin(result.origins, path, location, LayerCLI)
@@ -425,10 +423,9 @@ func applyPreparedOverride(result *composedDocument, override preparedOverride)
 				collectOverlayOrigins(result.origins, current.Mapping[position].Value, path, LayerCLI)
 			}
 		}
-		position = documentEntryIndex(current.Mapping, segment.key)
 		result.overlays = append(result.overlays, overlayRecord{change: Change{
 			Path: path.clone(), Origin: overlayOrigin(LayerCLI, location), Previous: previousOrigins(previous),
-		}, displaced: displaced, before: before, after: document.Clone(current.Mapping[position].Value)})
+		}, displaced: displaced})
 		result.applications = append(result.applications, historyApplication{
 			layer: LayerCLI, path: path.clone(), value: override.value,
 			origin: overlayOrigin(LayerCLI, location),