@@ -73,7 +73,7 @@ func env(req dispatchRequest) error {

 		}

 	}

-	return req.builder.commit("", req.runConfig.Cmd, commitMessage.String())

+	return req.builder.commit(commitMessage.String())

 }

 // MAINTAINER some text <maybe@an.email.address>

@@ -90,7 +90,7 @@ func maintainer(req dispatchRequest) error {

 	maintainer := req.args[0]

 	req.builder.maintainer = maintainer

-	return req.builder.commit("", req.runConfig.Cmd, "MAINTAINER "+maintainer)

+	return req.builder.commit("MAINTAINER " + maintainer)

 }

 // LABEL some json data describing the image

@@ -130,7 +130,7 @@ func label(req dispatchRequest) error {

 		req.runConfig.Labels[req.args[j]] = req.args[j+1]

 		j++

 	}

-	return req.builder.commit("", req.runConfig.Cmd, commitStr)

+	return req.builder.commit(commitStr)

 }

 // ADD foo /path

@@ -281,7 +281,7 @@ func onbuild(req dispatchRequest) error {

 	original := regexp.MustCompile(`(?i)^\s*ONBUILD\s*`).ReplaceAllString(req.original, "")

 	req.runConfig.OnBuild = append(req.runConfig.OnBuild, original)

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("ONBUILD %s", original))

+	return req.builder.commit("ONBUILD " + original)

 }

 // WORKDIR /tmp

@@ -321,10 +321,9 @@ func workdir(req dispatchRequest) error {

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

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

-	if hit, err := req.builder.probeCache(); err != nil {

+	// TODO: this should pass a copy of runConfig

+	if hit, err := req.builder.probeCache(req.builder.image, req.runConfig); err != nil || hit {

 		return err

-	} else if hit {

-		return nil

 	}

 	req.runConfig.Image = req.builder.image

@@ -341,7 +340,7 @@ func workdir(req dispatchRequest) error {

 		return err

 	}

-	return req.builder.commit(container.ID, cmd, comment)

+	return req.builder.commitContainer(container.ID, copyRunConfig(req.runConfig, withCmd(cmd)))

 }

 // RUN some command yo

@@ -402,13 +401,10 @@ func run(req dispatchRequest) error {

 	}

 	req.runConfig.Cmd = saveCmd

-	hit, err := req.builder.probeCache()

-	if err != nil {

+	hit, err := req.builder.probeCache(req.builder.image, req.runConfig)

+	if err != nil || hit {

 		return err

 	}

-	if hit {

-		return nil

-	}

 	// set Cmd manually, this is special case only for Dockerfiles

 	req.runConfig.Cmd = config.Cmd

@@ -419,7 +415,11 @@ func run(req dispatchRequest) error {

 	logrus.Debugf("[BUILDER] Command to be executed: %v", req.runConfig.Cmd)

-	cID, err := req.builder.create()

+	// TODO: this was previously in b.create(), why is it necessary?

+	req.builder.runConfig.Image = req.builder.image

+

+	// TODO: should pass a copy of runConfig

+	cID, err := req.builder.create(req.runConfig)

 	if err != nil {

 		return err

 	}

@@ -451,7 +451,7 @@ func run(req dispatchRequest) error {

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

 	}

 	req.runConfig.Cmd = saveCmd

-	return req.builder.commit(cID, cmd, "run")

+	return req.builder.commitContainer(cID, copyRunConfig(req.runConfig, withCmd(cmd)))

 }

 // CMD foo

@@ -474,7 +474,7 @@ func cmd(req dispatchRequest) error {

 	// set config as already being escaped, this prevents double escaping on windows

 	req.runConfig.ArgsEscaped = true

-	if err := req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("CMD %q", cmdSlice)); err != nil {

+	if err := req.builder.commit(fmt.Sprintf("CMD %q", cmdSlice)); err != nil {

 		return err

 	}

@@ -590,7 +590,7 @@ func healthcheck(req dispatchRequest) error {

 		req.runConfig.Healthcheck = &healthcheck

 	}

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("HEALTHCHECK %q", req.runConfig.Healthcheck))

+	return req.builder.commit(fmt.Sprintf("HEALTHCHECK %q", req.runConfig.Healthcheck))

 }

 // ENTRYPOINT /usr/sbin/nginx

@@ -626,11 +626,7 @@ func entrypoint(req dispatchRequest) error {

 		req.runConfig.Cmd = nil

 	}

-	if err := req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("ENTRYPOINT %q", req.runConfig.Entrypoint)); err != nil {

-		return err

-	}

-

-	return nil

+	return req.builder.commit(fmt.Sprintf("ENTRYPOINT %q", req.runConfig.Entrypoint))

 }

 // EXPOSE 6667/tcp 7000/tcp

@@ -671,7 +667,7 @@ func expose(req dispatchRequest) error {

 		i++

 	}

 	sort.Strings(portList)

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("EXPOSE %s", strings.Join(portList, " ")))

+	return req.builder.commit("EXPOSE " + strings.Join(portList, " "))

 }

 // USER foo

@@ -689,7 +685,7 @@ func user(req dispatchRequest) error {

 	}

 	req.runConfig.User = req.args[0]

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("USER %v", req.args))

+	return req.builder.commit(fmt.Sprintf("USER %v", req.args))

 }

 // VOLUME /foo

@@ -715,10 +711,7 @@ func volume(req dispatchRequest) error {

 		}

 		req.runConfig.Volumes[v] = struct{}{}

 	}

-	if err := req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("VOLUME %v", req.args)); err != nil {

-		return err

-	}

-	return nil

+	return req.builder.commit(fmt.Sprintf("VOLUME %v", req.args))

 }

 // STOPSIGNAL signal

@@ -736,7 +729,7 @@ func stopSignal(req dispatchRequest) error {

 	}

 	req.runConfig.StopSignal = sig

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("STOPSIGNAL %v", req.args))

+	return req.builder.commit(fmt.Sprintf("STOPSIGNAL %v", req.args))

 }

 // ARG name[=value]

@@ -786,7 +779,7 @@ func arg(req dispatchRequest) error {

 		req.builder.buildArgs.AddMetaArg(name, value)

 		return nil

 	}

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("ARG %s", arg))

+	return req.builder.commit("ARG " + arg)

 }

 // SHELL powershell -command

@@ -808,7 +801,7 @@ func shell(req dispatchRequest) error {

 		// SHELL powershell -command - not JSON

 		return errNotJSON("SHELL", req.original)

 	}

-	return req.builder.commit("", req.runConfig.Cmd, fmt.Sprintf("SHELL %v", shellSlice))

+	return req.builder.commit(fmt.Sprintf("SHELL %v", shellSlice))

 }

 func errAtLeastOneArgument(command string) error {

@@ -831,15 +824,6 @@ func errTooManyArguments(command string) error {

 	return fmt.Errorf("Bad input to %s, too many arguments", command)

 }

-// getShell is a helper function which gets the right shell for prefixing the

-// shell-form of RUN, ENTRYPOINT and CMD instructions

-func getShell(c *container.Config) []string {

-	if 0 == len(c.Shell) {

-		return append([]string{}, defaultShell[:]...)

-	}

-	return append([]string{}, c.Shell[:]...)

-}

-

 // mountByRef creates an imageMount from a reference. pulling the image if needed.

 func mountByRef(b *Builder, name string) (*imageMount, error) {

 	image, err := pullOrGetImage(b, name)

@@ -36,41 +36,39 @@ import (

 	"github.com/pkg/errors"

 )

-func (b *Builder) commit(id string, autoCmd strslice.StrSlice, comment string) error {

+func (b *Builder) commit(comment string) error {

 	if b.disableCommit {

 		return nil

 	}

 	if !b.hasFromImage() {

 		return errors.New("Please provide a source image with `from` prior to commit")

 	}

+	// TODO: why is this set here?

 	b.runConfig.Image = b.image

-	if id == "" {

-		cmd := b.runConfig.Cmd

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

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

-

-		hit, err := b.probeCache()

-		if err != nil {

-			return err

-		} else if hit {

-			return nil

-		}

-		id, err = b.create()

-		if err != nil {

-			return err

-		}

+	runConfigWithCommentCmd := copyRunConfig(b.runConfig, withCmdComment(comment))

+	hit, err := b.probeCache(b.image, runConfigWithCommentCmd)

+	if err != nil || hit {

+		return err

+	}

+	id, err := b.create(runConfigWithCommentCmd)

+	if err != nil {

+		return err

 	}

-	// Note: Actually copy the struct

-	autoConfig := *b.runConfig

-	autoConfig.Cmd = autoCmd

+	return b.commitContainer(id, b.runConfig)

+}

+

+func (b *Builder) commitContainer(id string, runConfig *container.Config) error {

+	if b.disableCommit {

+		return nil

+	}

 	commitCfg := &backend.ContainerCommitConfig{

 		ContainerCommitConfig: types.ContainerCommitConfig{

 			Author: b.maintainer,

 			Pause:  true,

-			Config: &autoConfig,

+			Config: runConfig,

 		},

 	}

@@ -80,8 +78,10 @@ func (b *Builder) commit(id string, autoCmd strslice.StrSlice, comment string) e

 		return err

 	}

+	// TODO: this function should return imageID and runConfig instead of setting

+	// then on the builder

 	b.image = imageID

-	b.imageContexts.update(imageID, &autoConfig)

+	b.imageContexts.update(imageID, runConfig)

 	return nil

 }

@@ -148,11 +148,9 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD

 	// For backwards compat, if there's just one info then use it as the

 	// cache look-up string, otherwise hash 'em all into one

 	var srcHash string

-	var origPaths string

 	if len(infos) == 1 {

 		info := infos[0]

-		origPaths = info.path

 		srcHash = info.hash

 	} else {

 		var hashs []string

@@ -164,17 +162,16 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD

 		hasher := sha256.New()

 		hasher.Write([]byte(strings.Join(hashs, ",")))

 		srcHash = "multi:" + hex.EncodeToString(hasher.Sum(nil))

-		origPaths = strings.Join(origs, " ")

 	}

 	cmd := b.runConfig.Cmd

+	// TODO: should this have been using origPaths instead of srcHash in the comment?

 	b.runConfig.Cmd = strslice.StrSlice(append(getShell(b.runConfig), fmt.Sprintf("#(nop) %s %s in %s ", cmdName, srcHash, dest)))

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

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

+	// TODO: this should pass a copy of runConfig

+	if hit, err := b.probeCache(b.image, b.runConfig); err != nil || hit {

 		return err

-	} else if hit {

-		return nil

 	}

 	container, err := b.docker.ContainerCreate(types.ContainerCreateConfig{

@@ -187,8 +184,6 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD

 	}

 	b.tmpContainers[container.ID] = struct{}{}

-	comment := fmt.Sprintf("%s %s in %s", cmdName, origPaths, dest)

-

 	// Twiddle the destination when it's a relative path - meaning, make it

 	// relative to the WORKINGDIR

 	if dest, err = normaliseDest(cmdName, b.runConfig.WorkingDir, dest); err != nil {

@@ -201,7 +196,44 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD

 		}

 	}

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

+	return b.commitContainer(container.ID, copyRunConfig(b.runConfig, withCmd(cmd)))

+}

+

+type runConfigModifier func(*container.Config)

+

+func copyRunConfig(runConfig *container.Config, modifiers ...runConfigModifier) *container.Config {

+	copy := *runConfig

+	for _, modifier := range modifiers {

+		modifier(&copy)

+	}

+	return &copy

+}

+

+func withCmd(cmd []string) runConfigModifier {

+	return func(runConfig *container.Config) {

+		runConfig.Cmd = cmd

+	}

+}

+

+func withCmdComment(comment string) runConfigModifier {

+	return func(runConfig *container.Config) {

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

+	}

+}

+

+func withEnv(env []string) runConfigModifier {

+	return func(runConfig *container.Config) {

+		runConfig.Env = env

+	}

+}

+

+// getShell is a helper function which gets the right shell for prefixing the

+// shell-form of RUN, ENTRYPOINT and CMD instructions

+func getShell(c *container.Config) []string {

+	if 0 == len(c.Shell) {

+		return append([]string{}, defaultShell[:]...)

+	}

+	return append([]string{}, c.Shell[:]...)

 }

 func (b *Builder) download(srcURL string) (remote builder.Source, p string, err error) {

@@ -498,35 +530,33 @@ func (b *Builder) processImageFrom(img builder.Image) error {

 // If an image is found, probeCache returns `(true, nil)`.

 // If no image is found, it returns `(false, nil)`.

 // If there is any error, it returns `(false, err)`.

-func (b *Builder) probeCache() (bool, error) {

+func (b *Builder) probeCache(imageID string, runConfig *container.Config) (bool, error) {

 	c := b.imageCache

 	if c == nil || b.options.NoCache || b.cacheBusted {

 		return false, nil

 	}

-	cache, err := c.GetCache(b.image, b.runConfig)

+	cache, err := c.GetCache(imageID, runConfig)

 	if err != nil {

 		return false, err

 	}

 	if len(cache) == 0 {

-		logrus.Debugf("[BUILDER] Cache miss: %s", b.runConfig.Cmd)

+		logrus.Debugf("[BUILDER] Cache miss: %s", runConfig.Cmd)

 		b.cacheBusted = true

 		return false, nil

 	}

 	fmt.Fprint(b.Stdout, " ---> Using cache\n")

-	logrus.Debugf("[BUILDER] Use cached version: %s", b.runConfig.Cmd)

+	logrus.Debugf("[BUILDER] Use cached version: %s", runConfig.Cmd)

 	b.image = string(cache)

-	b.imageContexts.update(b.image, b.runConfig)

+	b.imageContexts.update(b.image, runConfig)

 	return true, nil

 }

-func (b *Builder) create() (string, error) {

+func (b *Builder) create(runConfig *container.Config) (string, error) {

 	if !b.hasFromImage() {

 		return "", errors.New("Please provide a source image with `from` prior to run")

 	}

-	b.runConfig.Image = b.image

-

 	resources := container.Resources{

 		CgroupParent: b.options.CgroupParent,

 		CPUShares:    b.options.CPUShares,

@@ -551,11 +581,9 @@ func (b *Builder) create() (string, error) {

 		ExtraHosts: b.options.ExtraHosts,

 	}

-	config := *b.runConfig

-

 	// Create the container

 	c, err := b.docker.ContainerCreate(types.ContainerCreateConfig{

-		Config:     b.runConfig,

+		Config:     runConfig,

 		HostConfig: hostConfig,

 	})

 	if err != nil {

@@ -569,7 +597,7 @@ func (b *Builder) create() (string, error) {

 	fmt.Fprintf(b.Stdout, " ---> Running in %s\n", stringid.TruncateID(c.ID))

 	// override the entry point that may have been picked up from the base image

-	if err := b.docker.ContainerUpdateCmdOnBuild(c.ID, config.Cmd); err != nil {

+	if err := b.docker.ContainerUpdateCmdOnBuild(c.ID, runConfig.Cmd); err != nil {

 		return "", err

 	}

@@ -5,6 +5,7 @@ import (

 	"fmt"

 	"testing"

+	"github.com/docker/docker/api/types/container"

 	"github.com/docker/docker/builder"

 	"github.com/docker/docker/builder/remotecontext"

 	"github.com/docker/docker/pkg/archive"

@@ -71,3 +72,54 @@ func readAndCheckDockerfile(t *testing.T, testName, contextDir, dockerfilePath,

 	_, _, err = remotecontext.Detect(context.Background(), "", dockerfilePath, tarStream, nil)

 	assert.EqualError(t, err, expectedError)

 }

+

+func TestCopyRunConfig(t *testing.T) {

+	defaultEnv := []string{"foo=1"}

+	defaultCmd := []string{"old"}

+

+	var testcases = []struct {

+		doc       string

+		modifiers []runConfigModifier

+		expected  *container.Config

+	}{

+		{

+			doc:       "Set the command",

+			modifiers: []runConfigModifier{withCmd([]string{"new"})},

+			expected: &container.Config{

+				Cmd: []string{"new"},

+				Env: defaultEnv,

+			},

+		},

+		{

+			doc:       "Set the command to a comment",

+			modifiers: []runConfigModifier{withCmdComment("comment")},

+			expected: &container.Config{

+				Cmd: append(defaultShell, "#(nop) ", "comment"),

+				Env: defaultEnv,

+			},

+		},

+		{

+			doc: "Set the command and env",

+			modifiers: []runConfigModifier{

+				withCmd([]string{"new"}),

+				withEnv([]string{"one", "two"}),

+			},

+			expected: &container.Config{

+				Cmd: []string{"new"},

+				Env: []string{"one", "two"},

+			},

+		},

+	}

+

+	for _, testcase := range testcases {

+		runConfig := &container.Config{

+			Cmd: defaultCmd,

+			Env: defaultEnv,

+		}

+		runConfigCopy := copyRunConfig(runConfig, testcase.modifiers...)

+		assert.Equal(t, testcase.expected, runConfigCopy, testcase.doc)

+		// Assert the original was not modified

+		assert.NotEqual(t, runConfig, runConfigCopy, testcase.doc)

+	}

+

+}