@@ -26,7 +26,7 @@ github.com/imdario/mergo v0.3.6

 golang.org/x/sync 1d60e4601c6fd243af51cc01ddf169918a5407ca

 # buildkit

-github.com/moby/buildkit 8cf9bec86a7f11fe6591804aee152c8e8a7a8a0d # v0.3.3

+github.com/moby/buildkit d9f75920678e35090025bb89344c5370e2efc8e7

 github.com/tonistiigi/fsutil 2862f6bc5ac9b97124e552a5c108230b38a1b0ca

 github.com/grpc-ecosystem/grpc-opentracing 8e809c8a86450a29b90dcc9efbf062d0fe6d9746

 github.com/opentracing/opentracing-go 1361b9cd60be79c4c3a7fa9841b3c132e40066a7

@@ -145,13 +145,13 @@ build-using-dockerfile -t mybuildkit -f ./hack/dockerfiles/test.Dockerfile .

 docker inspect myimage

 ```

-##### Building a Dockerfile using [external frontend](https://hub.docker.com/r/tonistiigi/dockerfile/tags/):

+##### Building a Dockerfile using [external frontend](https://hub.docker.com/r/docker/dockerfile/tags/):

-During development, an external version of the Dockerfile frontend is pushed to https://hub.docker.com/r/tonistiigi/dockerfile that can be used with the gateway frontend. The source for the external frontend is currently located in `./frontend/dockerfile/cmd/dockerfile-frontend` but will move out of this repository in the future ([#163](https://github.com/moby/buildkit/issues/163)). For automatic build from master branch of this repository `tonistiigi/dockerfile:master` image can be used.

+External versions of the Dockerfile frontend are pushed to https://hub.docker.com/r/docker/dockerfile-upstream and https://hub.docker.com/r/docker/dockerfile and can be used with the gateway frontend. The source for the external frontend is currently located in `./frontend/dockerfile/cmd/dockerfile-frontend` but will move out of this repository in the future ([#163](https://github.com/moby/buildkit/issues/163)). For automatic build from master branch of this repository `docker/dockerfile-upsteam:master` or `docker/dockerfile-upstream:master-experimental` image can be used.

 ```

-buildctl build --frontend=gateway.v0 --frontend-opt=source=tonistiigi/dockerfile --local context=. --local dockerfile=.

-buildctl build --frontend gateway.v0 --frontend-opt=source=tonistiigi/dockerfile --frontend-opt=context=git://github.com/moby/moby --frontend-opt build-arg:APT_MIRROR=cdn-fastly.deb.debian.org

+buildctl build --frontend=gateway.v0 --frontend-opt=source=docker/dockerfile --local context=. --local dockerfile=.

+buildctl build --frontend gateway.v0 --frontend-opt=source=docker/dockerfile --frontend-opt=context=git://github.com/moby/moby --frontend-opt build-arg:APT_MIRROR=cdn-fastly.deb.debian.org

 ````

 ##### Building a Dockerfile with experimental features like `RUN --mount=type=(bind|cache|tmpfs|secret|ssh)`

@@ -44,7 +44,8 @@ func GenerateSpec(ctx context.Context, meta executor.Meta, mounts []executor.Mou

 	s.Process.Args = meta.Args

 	s.Process.Env = meta.Env

 	s.Process.Cwd = meta.Cwd

-	s.Process.Rlimits = nil // reset open files limit

+	s.Process.Rlimits = nil           // reset open files limit

+	s.Process.NoNewPrivileges = false // reset nonewprivileges

 	s.Hostname = "buildkitsandbox"

 	s.Mounts = GetMounts(ctx,

@@ -250,7 +250,6 @@ func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State,

 								}

 							}

 							d.stage.BaseName = ref.String()

-							_ = ref

 							if len(img.RootFS.DiffIDs) == 0 {

 								isScratch = true

 								// schema1 images can't return diffIDs so double check :(

@@ -89,7 +89,6 @@ func New(req Request) *Pipe {

 	roundTripCh := &channel{}

 	pw := &sender{

 		req:         req,

-		recvChannel: cancelCh,

 		sendChannel: roundTripCh,

 	}

 	pr := &receiver{

@@ -125,7 +124,6 @@ func New(req Request) *Pipe {

 type sender struct {

 	status      Status

 	req         Request

-	recvChannel *channel

 	sendChannel *channel

 	mu          sync.Mutex

 }

@@ -37,17 +37,20 @@ type gitSource struct {

 	locker *locker.Locker

 }

+// Supported returns nil if the system supports Git source

+func Supported() error {

+	if err := exec.Command("git", "version").Run(); err != nil {

+		return errors.Wrap(err, "failed to find git binary")

+	}

+	return nil

+}

+

 func NewSource(opt Opt) (source.Source, error) {

 	gs := &gitSource{

 		md:     opt.MetadataStore,

 		cache:  opt.CacheAccessor,

 		locker: locker.New(),

 	}

-

-	if err := exec.Command("git", "version").Run(); err != nil {

-		return nil, errors.Wrap(err, "failed to find git binary")

-	}

-

 	return gs, nil

 }