@@ -408,9 +408,7 @@ func run(b *Builder, args []string, attributes map[string]bool, original string)

 	// that starts with "foo=abc" to be considered part of a build-time env var.

 	saveCmd := config.Cmd

 	if len(cmdBuildEnv) > 0 {

-		sort.Strings(cmdBuildEnv)

-		tmpEnv := append([]string{fmt.Sprintf("|%d", len(cmdBuildEnv))}, cmdBuildEnv...)

-		saveCmd = strslice.StrSlice(append(tmpEnv, saveCmd...))

+		saveCmd = prependEnvOnCmd(b.buildArgs, cmdBuildEnv, saveCmd)

 	}

 	b.runConfig.Cmd = saveCmd

@@ -445,25 +443,24 @@ func run(b *Builder, args []string, attributes map[string]bool, original string)

 	// properly match it.

 	b.runConfig.Env = env

-	// remove builtinAllowedBuildArgs (see: builder.go)  from the saveCmd

-	// these args are transparent so resulting image should be the same regardless of the value

-	if len(cmdBuildEnv) > 0 {

-		saveCmd = config.Cmd

-		var tmpBuildEnv []string

-		for _, env := range cmdBuildEnv {

-			key := strings.SplitN(env, "=", 2)[0]

-			if !b.buildArgs.IsUnreferencedBuiltin(key) {

-				tmpBuildEnv = append(tmpBuildEnv, env)

-			}

-		}

-		sort.Strings(tmpBuildEnv)

-		tmpEnv := append([]string{fmt.Sprintf("|%d", len(tmpBuildEnv))}, tmpBuildEnv...)

-		saveCmd = strslice.StrSlice(append(tmpEnv, saveCmd...))

-	}

 	b.runConfig.Cmd = saveCmd

 	return b.commit(cID, cmd, "run")

 }

+func prependEnvOnCmd(buildArgs *buildArgs, buildArgVars []string, cmd strslice.StrSlice) strslice.StrSlice {

+	var tmpBuildEnv []string

+	for _, env := range buildArgVars {

+		key := strings.SplitN(env, "=", 2)[0]

+		if !buildArgs.IsUnreferencedBuiltin(key) {

+			tmpBuildEnv = append(tmpBuildEnv, env)

+		}

+	}

+

+	sort.Strings(tmpBuildEnv)

+	tmpEnv := append([]string{fmt.Sprintf("|%d", len(tmpBuildEnv))}, tmpBuildEnv...)

+	return strslice.StrSlice(append(tmpEnv, cmd...))

+}

+

 // CMD foo

 //

 // Set the default command to run in the container (which may be empty).

@@ -4344,15 +4344,22 @@ func (s *DockerSuite) TestBuildTimeArgHistoryExclusions(c *check.C) {

 		ARG %s

 		ARG %s

 		RUN echo "Testing Build Args!"`, envKey, explicitProxyKey)

-	buildImage(imgName,

-		cli.WithFlags("--build-arg", "https_proxy=https://proxy.example.com",

-			"--build-arg", fmt.Sprintf("%s=%s", envKey, envVal),

-			"--build-arg", fmt.Sprintf("%s=%s", explicitProxyKey, explicitProxyVal),

-			"--build-arg", proxy),

-		build.WithDockerfile(dockerfile),

-	).Assert(c, icmd.Success)

-	out, _ := dockerCmd(c, "history", "--no-trunc", imgName)

+	buildImage := func(imgName string) string {

+		cli.BuildCmd(c, imgName,

+			cli.WithFlags("--build-arg", "https_proxy=https://proxy.example.com",

+				"--build-arg", fmt.Sprintf("%s=%s", envKey, envVal),

+				"--build-arg", fmt.Sprintf("%s=%s", explicitProxyKey, explicitProxyVal),

+				"--build-arg", proxy),

+			build.WithDockerfile(dockerfile),

+		)

+		return getIDByName(c, imgName)

+	}

+

+	origID := buildImage(imgName)

+	result := cli.DockerCmd(c, "history", "--no-trunc", imgName)

+	out := result.Stdout()

+

 	if strings.Contains(out, proxy) {

 		c.Fatalf("failed to exclude proxy settings from history!")

 	}

@@ -4365,6 +4372,9 @@ func (s *DockerSuite) TestBuildTimeArgHistoryExclusions(c *check.C) {

 	if !strings.Contains(out, fmt.Sprintf("%s=%s", envKey, envVal)) {

 		c.Fatalf("missing build arguments from output")

 	}

+

+	cacheID := buildImage(imgName + "-two")

+	c.Assert(origID, checker.Equals, cacheID)

 }

 func (s *DockerSuite) TestBuildBuildTimeArgCacheHit(c *check.C) {