From a1acbe8aa82fae7541ce29759cb94f989b9a57f4 Mon Sep 17 00:00:00 2001
From: Priya Wadhwa <priyawadhwa@google.com>
Date: Mon, 30 Apr 2018 22:37:45 -0400
Subject: [PATCH] Fixed ResolveStages

---
 pkg/dockerfile/dockerfile.go | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/pkg/dockerfile/dockerfile.go b/pkg/dockerfile/dockerfile.go
index c3eb8ed95..dd2f0311c 100644
--- a/pkg/dockerfile/dockerfile.go
+++ b/pkg/dockerfile/dockerfile.go
@@ -53,13 +53,16 @@ func ResolveStages(stages []instructions.Stage) {
 	nameToIndex := make(map[string]string)
 	for i, stage := range stages {
 		index := strconv.Itoa(i)
-		nameToIndex[stage.Name] = index
-		nameToIndex[index] = index
+		if stage.Name != index {
+			nameToIndex[stage.Name] = index
+		}
 		for _, cmd := range stage.Commands {
 			switch c := cmd.(type) {
 			case *instructions.CopyCommand:
 				if c.From != "" {
-					c.From = nameToIndex[c.From]
+					if val, ok := nameToIndex[c.From]; ok {
+						c.From = val
+					}
 				}
 			}
 		}