@@ -79,8 +79,8 @@ func ToParamWithVersion(version string, a Args) (string, error) {

 	}

 	// for daemons older than v1.10, filter must be of the form map[string][]string

-	buf := []byte{}

-	err := errors.New("")

+	var buf []byte

+	var err error

 	if version != "" && versions.LessThan(version, "1.22") {

 		buf, err = json.Marshal(convertArgsToSlice(a.fields))

 	} else {

@@ -204,10 +204,7 @@ func from(b *Builder, args []string, attributes map[string]bool, original string

 	name := args[0]

-	var (

-		image builder.Image

-		err   error

-	)

+	var image builder.Image

 	// Windows cannot support a container with no base image.

 	if name == api.NoBaseImageSpecifier {

@@ -219,10 +216,11 @@ func from(b *Builder, args []string, attributes map[string]bool, original string

 	} else {

 		// TODO: don't use `name`, instead resolve it to a digest

 		if !b.options.PullParent {

-			image, err = b.docker.GetImageOnBuild(name)

+			image, _ = b.docker.GetImageOnBuild(name)

 			// TODO: shouldn't we error out if error is different from "not found" ?

 		}

 		if image == nil {

+			var err error

 			image, err = b.docker.PullOnBuild(b.clientCtx, name, b.options.AuthConfigs, b.Output)

 			if err != nil {

 				return err

@@ -113,7 +113,6 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD

 	var err error

 	for _, orig := range args[0 : len(args)-1] {

 		var fi builder.FileInfo

-		decompress := allowLocalDecompression

 		if urlutil.IsURL(orig) {

 			if !allowRemote {

 				return fmt.Errorf("Source can't be a URL for %s", cmdName)

@@ -123,8 +122,10 @@ func (b *Builder) runContextCommand(args []string, allowRemote bool, allowLocalD

 				return err

 			}

 			defer os.RemoveAll(filepath.Dir(fi.Path()))

-			decompress = false

-			infos = append(infos, copyInfo{fi, decompress})

+			infos = append(infos, copyInfo{

+				FileInfo:   fi,

+				decompress: false,

+			})

 			continue

 		}

 		// not a URL

@@ -81,14 +81,11 @@ func collect(ctx context.Context, s *formatter.ContainerStats, cli client.APICli

 	go func() {

 		for {

 			var (

-				v                 *types.StatsJSON

-				memPercent        = 0.0

-				cpuPercent        = 0.0

-				blkRead, blkWrite uint64 // Only used on Linux

-				mem               = 0.0

-				memLimit          = 0.0

-				memPerc           = 0.0

-				pidsStatsCurrent  uint64

+				v                      *types.StatsJSON

+				memPercent, cpuPercent float64

+				blkRead, blkWrite      uint64 // Only used on Linux

+				mem, memLimit, memPerc float64

+				pidsStatsCurrent       uint64

 			)

 			if err := dec.Decode(&v); err != nil {

@@ -41,7 +41,9 @@ func validateConfig(path string) error {

 // validateContextDir validates the given dir and returns abs path on success.

 func validateContextDir(contextDir string) (string, error) {

 	absContextDir, err := filepath.Abs(contextDir)

-

+	if err != nil {

+		return "", err

+	}

 	stat, err := os.Lstat(absContextDir)

 	if err != nil {

 		return "", err

@@ -497,7 +497,7 @@ func UsingSystemd(config *Config) bool {

 // verifyPlatformContainerSettings performs platform-specific validation of the

 // hostconfig and config structures.

 func verifyPlatformContainerSettings(daemon *Daemon, hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) ([]string, error) {

-	warnings := []string{}

+	var warnings []string

 	sysInfo := sysinfo.New(true)

 	warnings, err := daemon.verifyExperimentalContainerSettings(hostConfig, config)

@@ -925,7 +925,6 @@ func parseRemappedRoot(usergrp string) (string, string, error) {

 			if err != nil {

 				return "", "", fmt.Errorf("Error during gid lookup for %q: %v", lookupName, err)

 			}

-			groupID = group.Gid

 			groupname = group.Name

 		}

 	}

@@ -64,7 +64,7 @@ func (daemon *Daemon) createSpec(c *container.Container) (*specs.Spec, error) {

 	s.Process.User.Username = c.Config.User

 	// In spec.Root. This is not set for Hyper-V containers

-	isHyperV := false

+	var isHyperV bool

 	if c.HostConfig.Isolation.IsDefault() {

 		// Container using default isolation, so take the default from the daemon configuration

 		isHyperV = daemon.defaultIsolation.IsHyperV()

@@ -121,7 +121,7 @@ type v1DependencyImage struct {

 func newV1DependencyImage(l layer.Layer, parent *v1DependencyImage) *v1DependencyImage {

 	v1ID := digest.Digest(l.ChainID()).Hex()

-	config := ""

+	var config string

 	if parent != nil {

 		config = fmt.Sprintf(`{"id":"%s","parent":"%s"}`, v1ID, parent.V1ID())

 	} else {

@@ -29,7 +29,7 @@ type applyLayerResponse struct {

 func applyLayer() {

 	var (

-		tmpDir  = ""

+		tmpDir  string

 		err     error

 		options *archive.TarOptions

 	)

@@ -35,7 +35,6 @@ func IsKilled(err error) bool {

 }

 func runCommandWithOutput(cmd *exec.Cmd) (output string, exitCode int, err error) {

-	exitCode = 0

 	out, err := cmd.CombinedOutput()

 	exitCode = system.ProcessExitCode(err)

 	output = string(out)

@@ -290,7 +290,7 @@ func (r *Session) GetRemoteImageLayer(imgID, registry string, imgSize int64) (io

 	if err != nil {

 		return nil, fmt.Errorf("Error while getting from the server: %v", err)

 	}

-	statusCode = 0

+

 	res, err = r.client.Do(req)

 	if err != nil {

 		logrus.Debugf("Error contacting registry %s: %v", registry, err)

@@ -200,12 +200,12 @@ func GetAllDrivers() ([]volume.Driver, error) {

 	for _, p := range plugins {

 		name := p.Name()

-		ext, ok := drivers.extensions[name]

-		if ok {

+

+		if _, ok := drivers.extensions[name]; ok {

 			continue

 		}

-		ext = NewVolumeDriver(name, p.BasePath(), p.Client())

+		ext := NewVolumeDriver(name, p.BasePath(), p.Client())

 		if p.IsV1() {

 			drivers.extensions[name] = ext

 		}