From 46aff8bcc4b38a51fda8ac18faf50034412f664e Mon Sep 17 00:00:00 2001
From: Alex Goodman <wagoodman@gmail.com>
Date: Mon, 18 Feb 2019 08:48:14 -0500
Subject: [PATCH] reference layer data for source of truth on index

---
 filetree/node.go      |  1 -
 image/docker_image.go | 10 +++++-----
 runtime/export.go     |  2 +-
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/filetree/node.go b/filetree/node.go
index f9b2eb4..8447602 100644
--- a/filetree/node.go
+++ b/filetree/node.go
@@ -303,7 +303,6 @@ func (node *FileNode) compare(other *FileNode) DiffType {
 	if node.Name != other.Name {
 		panic("comparing mismatched nodes")
 	}
-	// TODO: fails on nil
 
 	return node.Data.FileInfo.Compare(other.Data.FileInfo)
 }
diff --git a/image/docker_image.go b/image/docker_image.go
index ca259ab..ef415ef 100644
--- a/image/docker_image.go
+++ b/image/docker_image.go
@@ -140,18 +140,18 @@ func (image *dockerImageAnalyzer) Analyze() (*AnalysisResult, error) {
 	// as you iterate chronologically through history (ignoring history items that have no layer contents)
 	layerIdx := len(image.trees) - 1
 	tarPathIdx := 0
-	for idx := 0; idx < len(config.History); idx++ {
+	for histIdx := 0; histIdx < len(config.History); histIdx++ {
 		// ignore empty layers, we are only observing layers with content
-		if config.History[idx].EmptyLayer {
+		if config.History[histIdx].EmptyLayer {
 			continue
 		}
 
 		tree := image.trees[(len(image.trees)-1)-layerIdx]
-		config.History[idx].Size = uint64(tree.FileSize)
+		config.History[histIdx].Size = uint64(tree.FileSize)
 
 		image.layers[layerIdx] = &dockerLayer{
-			history: config.History[idx],
-			index:   layerIdx,
+			history: config.History[histIdx],
+			index:   tarPathIdx,
 			tree:    image.trees[layerIdx],
 			tarPath: manifest.LayerTarPaths[tarPathIdx],
 		}
diff --git a/runtime/export.go b/runtime/export.go
index 39673be..48f768a 100644
--- a/runtime/export.go
+++ b/runtime/export.go
@@ -17,7 +17,7 @@ func newExport(analysis *image.AnalysisResult) *export {
 		idx := (len(analysis.Layers) - 1) - revIdx
 
 		data.Layer[idx] = exportLayer{
-			Index:     idx,
+			Index:     layer.Index(),
 			DigestID:  layer.Id(),
 			SizeBytes: layer.Size(),
 			Command:   layer.Command(),