@@ -309,7 +309,5 @@ func (b *Builder) dispatch(stepN int, ast *parser.Node) error {

 		return f(b, strList, attrs, original)

 	}

-	fmt.Fprintf(b.ErrStream, "# Skipping unknown instruction %s\n", strings.ToUpper(cmd))

-

-	return nil

+	return fmt.Errorf("Unknown instruction: %s", strings.ToUpper(cmd))

 }

@@ -15,6 +15,9 @@ For a complete list of patches, fixes, and other improvements, see the

 *New Features*

+* [1.6] The Docker daemon will no longer ignore unknown commands

+  while processing a `Dockerfile`. Instead it will generate an error and halt

+  processing.

 * The Docker daemon has now supports for IPv6 networking between containers

   and on the `docker0` bridge. For more information see the

   [IPv6 networking reference](/articles/networking/#ipv6).

@@ -22,7 +25,7 @@ For a complete list of patches, fixes, and other improvements, see the

   container to writing to volumes [PR# 10093](https://github.com/docker/docker/pull/10093).

 * A new `docker stats CONTAINERID` command has been added to allow users to view a

   continuously updating stream of container resource usage statistics. See the

-  [`stats` command line reference](/reference/commandline/cli/#stats) and the 

+  [`stats` command line reference](/reference/commandline/cli/#stats) and the

   [container `stats` API reference](/reference/api/docker_remote_api_v1.17/#get-container-stats-based-on-resource-usage).

   **Note**: this feature is only enabled for the `libcontainer` exec-driver at this point.

 * Users can now specify the file to use as the `Dockerfile` by running

@@ -4343,16 +4343,16 @@ func TestBuildCmdJSONNoShDashC(t *testing.T) {

 	logDone("build - cmd should not have /bin/sh -c for json")

 }

-func TestBuildIgnoreInvalidInstruction(t *testing.T) {

+func TestBuildErrorInvalidInstruction(t *testing.T) {

 	name := "testbuildignoreinvalidinstruction"

 	defer deleteImages(name)

 	out, _, err := buildImageWithOut(name, "FROM busybox\nfoo bar", true)

-	if err != nil {

-		t.Fatal(err, out)

+	if err == nil {

+		t.Fatalf("Should have failed: %s", out)

 	}

-	logDone("build - ignore invalid Dockerfile instruction")

+	logDone("build - error invalid Dockerfile instruction")

 }

 func TestBuildEntrypointInheritance(t *testing.T) {