@@ -297,17 +297,19 @@ func workdir(b *Builder, args []string, attributes map[string]bool, original str

 	}

 	b.runConfig.Image = b.image

+	cmd := b.runConfig.Cmd

+	comment := "WORKDIR " + b.runConfig.WorkingDir

+	// reset the command for cache detection

+	b.runConfig.Cmd = strslice.StrSlice(append(getShell(b.runConfig), "#(nop) "+comment))

+	defer func(cmd strslice.StrSlice) { b.runConfig.Cmd = cmd }(cmd)

+

 	if hit, err := b.probeCache(); err != nil {

 		return err

 	} else if hit {

 		return nil

 	}

-	// Actually copy the struct

-	workdirConfig := *b.runConfig

-	workdirConfig.Cmd = strslice.StrSlice(append(getShell(b.runConfig), fmt.Sprintf("#(nop) WORKDIR %s", b.runConfig.WorkingDir)))

-

-	container, err := b.docker.ContainerCreate(types.ContainerCreateConfig{Config: &workdirConfig})

+	container, err := b.docker.ContainerCreate(types.ContainerCreateConfig{Config: b.runConfig})

 	if err != nil {

 		return err

 	}

@@ -316,7 +318,7 @@ func workdir(b *Builder, args []string, attributes map[string]bool, original str

 		return err

 	}

-	return b.commit(container.ID, b.runConfig.Cmd, "WORKDIR "+b.runConfig.WorkingDir)

+	return b.commit(container.ID, cmd, comment)

 }

 // RUN some command yo

@@ -7394,6 +7394,10 @@ func (s *DockerSuite) TestBuildWorkdirCmd(c *check.C) {

                 FROM golang:1.7-alpine

                 WORKDIR /

                 `

-	_, err := buildImage("testbuildworkdircmd", dockerFile, false)

+	_, err := buildImage("testbuildworkdircmd", dockerFile, true)

 	c.Assert(err, checker.IsNil)

+

+	_, out, err := buildImageWithOut("testbuildworkdircmd", dockerFile, true)

+	c.Assert(err, checker.IsNil)

+	c.Assert(strings.Count(out, "Using cache"), checker.Equals, 1)

 }