Integrate heredoc support into ADD/COPY and RUN

This modifies the command structures to support inline files, as well as
provides the logic to compile them down into appropriate LLB
definitions.

Signed-off-by: Justin Chadwell <me@jedevc.com>

frontend/dockerfile/dockerfile2llb/convert.go

@@ -507,7 +507,7 @@ func dispatch(d *dispatchState, cmd command, opt dispatchOpt) error {
 	case *instructions.AddCommand:
 		err = dispatchCopy(d, c.SourcesAndDest, opt.buildContext, true, c, c.Chown, c.Chmod, c.Location(), opt)
 		if err == nil {
-			for _, src := range c.Sources() {
+			for _, src := range c.SourcePaths {
 				if !strings.HasPrefix(src, "http://") && !strings.HasPrefix(src, "https://") {
 					d.ctxPaths[path.Join("/", filepath.ToSlash(src))] = struct{}{}
 				}
@@ -542,7 +542,7 @@ func dispatch(d *dispatchState, cmd command, opt dispatchOpt) error {
 		}
 		err = dispatchCopy(d, c.SourcesAndDest, l, false, c, c.Chown, c.Chmod, c.Location(), opt)
 		if err == nil && len(cmd.sources) == 0 {
-			for _, src := range c.Sources() {
+			for _, src := range c.SourcePaths {
 				d.ctxPaths[path.Join("/", filepath.ToSlash(src))] = struct{}{}
 			}
 		}
@@ -647,15 +647,63 @@ func dispatchEnv(d *dispatchState, c *instructions.EnvCommand) error {
 }
 
 func dispatchRun(d *dispatchState, c *instructions.RunCommand, proxy *llb.ProxyEnv, sources []*dispatchState, dopt dispatchOpt) error {
+	var opt []llb.RunOption
+
 	var args []string = c.CmdLine
+	if len(c.Files) > 0 {
+		if len(args) != 1 {
+			return fmt.Errorf("parsing produced an invalid run command: %v", args)
+		}
+
+		if heredoc := parser.MustParseHeredoc(args[0]); heredoc != nil {
+			if d.image.OS != "windows" && strings.HasPrefix(c.Files[0].Data, "#!") {
+				// This is a single heredoc with a shebang, so create a file
+				// and run it.
+				// NOTE: choosing to expand doesn't really make sense here, so
+				// we silently ignore that option if it was provided.
+				sourcePath := "/"
+				destPath := "/dev/pipes/"
+
+				f := c.Files[0].Name
+				data := c.Files[0].Data
+				if c.Files[0].Chomp {
+					data = parser.ChompHeredocContent(data)
+				}
+				st := llb.Scratch().Dir(sourcePath).File(llb.Mkfile(f, 0755, []byte(data)))
+
+				mount := llb.AddMount(destPath, st, llb.SourcePath(sourcePath), llb.Readonly)
+				opt = append(opt, mount)
+
+				args[0] = path.Join(destPath, f)
+			} else {
+				// Just a simple heredoc, so just run the contents in the
+				// shell: this creates the effect of a "fake"-heredoc, so that
+				// the syntax can still be used for shells that don't support
+				// heredocs directly.
+				// NOTE: like above, we ignore the expand option.
+				data := c.Files[0].Data
+				if c.Files[0].Chomp {
+					data = parser.ChompHeredocContent(data)
+				}
+				args[0] = data
+			}
+		} else {
+			// More complex heredoc, so reconstitute it, and pass it to the
+			// shell to handle.
+			for _, file := range c.Files {
+				args[0] += "\n" + file.Data + file.Name
+			}
+		}
+	}
 	if c.PrependShell {
 		args = withShell(d.image, args)
 	}
+
 	env, err := d.state.Env(context.TODO())
 	if err != nil {
 		return err
 	}
-	opt := []llb.RunOption{llb.Args(args), dfCmd(c), location(dopt.sourceMap, c.Location())}
+	opt = append(opt, llb.Args(args), dfCmd(c), location(dopt.sourceMap, c.Location()))
 	if d.ignoreCache {
 		opt = append(opt, llb.IgnoreCache)
 	}
@@ -735,12 +783,12 @@ func dispatchWorkdir(d *dispatchState, c *instructions.WorkdirCommand, commit bo
 }
 
 func dispatchCopyFileOp(d *dispatchState, c instructions.SourcesAndDest, sourceState llb.State, isAddCommand bool, cmdToPrint fmt.Stringer, chown string, chmod string, loc []parser.Range, opt dispatchOpt) error {
-	pp, err := pathRelativeToWorkingDir(d.state, c.Dest())
+	pp, err := pathRelativeToWorkingDir(d.state, c.DestPath)
 	if err != nil {
 		return err
 	}
 	dest := path.Join("/", pp)
-	if c.Dest() == "." || c.Dest() == "" || c.Dest()[len(c.Dest())-1] == filepath.Separator {
+	if c.DestPath == "." || c.DestPath == "" || c.DestPath[len(c.DestPath)-1] == filepath.Separator {
 		dest += string(filepath.Separator)
 	}
 
@@ -768,7 +816,7 @@ func dispatchCopyFileOp(d *dispatchState, c instructions.SourcesAndDest, sourceS
 
 	var a *llb.FileAction
 
-	for _, src := range c.Sources() {
+	for _, src := range c.SourcePaths {
 		commitMessage.WriteString(" " + src)
 		if strings.HasPrefix(src, "http://") || strings.HasPrefix(src, "https://") {
 			if !isAddCommand {
@@ -818,7 +866,24 @@ func dispatchCopyFileOp(d *dispatchState, c instructions.SourcesAndDest, sourceS
 		}
 	}
 
-	commitMessage.WriteString(" " + c.Dest())
+	for _, src := range c.SourceContents {
+		data := src.Data
+		f := src.Path
+		st := llb.Scratch().Dir("/").File(llb.Mkfile(f, 0664, []byte(data)))
+
+		opts := append([]llb.CopyOption{&llb.CopyInfo{
+			Mode:           mode,
+			CreateDestPath: true,
+		}}, copyOpt...)
+
+		if a == nil {
+			a = llb.Copy(st, f, dest, opts...)
+		} else {
+			a = a.Copy(st, f, dest, opts...)
+		}
+	}
+
+	commitMessage.WriteString(" " + c.DestPath)
 
 	platform := opt.targetPlatform
 	if d.platform != nil {
@@ -847,6 +912,10 @@ func dispatchCopy(d *dispatchState, c instructions.SourcesAndDest, sourceState l
 		return dispatchCopyFileOp(d, c, sourceState, isAddCommand, cmdToPrint, chown, chmod, loc, opt)
 	}
 
+	if len(c.SourceContents) > 0 {
+		return errors.New("inline content copy is not supported")
+	}
+
 	if chmod != "" {
 		if opt.llbCaps != nil && opt.llbCaps.Supports(pb.CapFileBase) != nil {
 			return errors.Wrap(opt.llbCaps.Supports(pb.CapFileBase), "chmod is not supported")
@@ -855,18 +924,18 @@ func dispatchCopy(d *dispatchState, c instructions.SourcesAndDest, sourceState l
 	}
 
 	img := llb.Image(opt.copyImage, llb.MarkImageInternal, llb.Platform(opt.buildPlatforms[0]), WithInternalName("helper image for file operations"))
-	pp, err := pathRelativeToWorkingDir(d.state, c.Dest())
+	pp, err := pathRelativeToWorkingDir(d.state, c.DestPath)
 	if err != nil {
 		return err
 	}
 	dest := path.Join(".", pp)
-	if c.Dest() == "." || c.Dest() == "" || c.Dest()[len(c.Dest())-1] == filepath.Separator {
+	if c.DestPath == "." || c.DestPath == "" || c.DestPath[len(c.DestPath)-1] == filepath.Separator {
 		dest += string(filepath.Separator)
 	}
 	args := []string{"copy"}
 	unpack := isAddCommand
 
-	mounts := make([]llb.RunOption, 0, len(c.Sources()))
+	mounts := make([]llb.RunOption, 0, len(c.SourcePaths))
 	if chown != "" {
 		args = append(args, fmt.Sprintf("--chown=%s", chown))
 		_, _, err := parseUser(chown)
@@ -883,7 +952,7 @@ func dispatchCopy(d *dispatchState, c instructions.SourcesAndDest, sourceState l
 		commitMessage.WriteString("COPY")
 	}
 
-	for i, src := range c.Sources() {
+	for i, src := range c.SourcePaths {
 		commitMessage.WriteString(" " + src)
 		if strings.HasPrefix(src, "http://") || strings.HasPrefix(src, "https://") {
 			if !isAddCommand {
@@ -920,7 +989,7 @@ func dispatchCopy(d *dispatchState, c instructions.SourcesAndDest, sourceState l
 		}
 	}
 
-	commitMessage.WriteString(" " + c.Dest())
+	commitMessage.WriteString(" " + c.DestPath)
 
 	args = append(args, dest)
 	if unpack {

frontend/dockerfile/instructions/commands.go

@@ -165,19 +165,45 @@ func (c *LabelCommand) Expand(expander SingleWordExpander) error {
 	return expandKvpsInPlace(c.Labels, expander)
 }
 
-// SourcesAndDest represent a list of source files and a destination
-type SourcesAndDest []string
-
-// Sources list the source paths
-func (s SourcesAndDest) Sources() []string {
-	res := make([]string, len(s)-1)
-	copy(res, s[:len(s)-1])
-	return res
+// SourceContent represents an anonymous file object
+type SourceContent struct {
+	Path   string
+	Data   string
+	Expand bool
 }
 
-// Dest path of the operation
-func (s SourcesAndDest) Dest() string {
-	return s[len(s)-1]
+// SourcesAndDest represent a collection of sources and a destination
+type SourcesAndDest struct {
+	DestPath       string
+	SourcePaths    []string
+	SourceContents []SourceContent
+}
+
+func (s *SourcesAndDest) Expand(expander SingleWordExpander) error {
+	for i, content := range s.SourceContents {
+		if !content.Expand {
+			continue
+		}
+
+		expandedData, err := expander(content.Data)
+		if err != nil {
+			return err
+		}
+		s.SourceContents[i].Data = expandedData
+	}
+
+	err := expandSliceInPlace(s.SourcePaths, expander)
+	if err != nil {
+		return err
+	}
+
+	expandedDestPath, err := expander(s.DestPath)
+	if err != nil {
+		return err
+	}
+	s.DestPath = expandedDestPath
+
+	return nil
 }
 
 // AddCommand : ADD foo /path
@@ -199,7 +225,8 @@ func (c *AddCommand) Expand(expander SingleWordExpander) error {
 		return err
 	}
 	c.Chown = expandedChown
-	return expandSliceInPlace(c.SourcesAndDest, expander)
+
+	return c.SourcesAndDest.Expand(expander)
 }
 
 // CopyCommand : COPY foo /path
@@ -221,7 +248,8 @@ func (c *CopyCommand) Expand(expander SingleWordExpander) error {
 		return err
 	}
 	c.Chown = expandedChown
-	return expandSliceInPlace(c.SourcesAndDest, expander)
+
+	return c.SourcesAndDest.Expand(expander)
 }
 
 // OnbuildCommand : ONBUILD <some other command>
@@ -249,9 +277,17 @@ func (c *WorkdirCommand) Expand(expander SingleWordExpander) error {
 	return nil
 }
 
+// ShellInlineFile represents an inline file created for a shell command
+type ShellInlineFile struct {
+	Name  string
+	Data  string
+	Chomp bool
+}
+
 // ShellDependantCmdLine represents a cmdline optionally prepended with the shell
 type ShellDependantCmdLine struct {
 	CmdLine      strslice.StrSlice
+	Files        []ShellInlineFile
 	PrependShell bool
 }
 

frontend/dockerfile/instructions/parse.go

@@ -18,6 +18,7 @@ import (
 type parseRequest struct {
 	command    string
 	args       []string
+	heredocs   []parser.Heredoc
 	attributes map[string]bool
 	flags      *BFlags
 	original   string
@@ -47,6 +48,7 @@ func newParseRequestFromNode(node *parser.Node) parseRequest {
 	return parseRequest{
 		command:    node.Value,
 		args:       nodeArgs(node),
+		heredocs:   node.Heredocs,
 		attributes: node.Attributes,
 		original:   node.Original,
 		flags:      NewBFlagsWithArgs(node.Flags),
@@ -236,6 +238,45 @@ func parseLabel(req parseRequest) (*LabelCommand, error) {
 	}, nil
 }
 
+func parseSourcesAndDest(req parseRequest, command string) (*SourcesAndDest, error) {
+	srcs := req.args[:len(req.args)-1]
+	dest := req.args[len(req.args)-1]
+	if heredoc := parser.MustParseHeredoc(dest); heredoc != nil {
+		return nil, errBadHeredoc(command, "a destination")
+	}
+
+	heredocLookup := make(map[string]parser.Heredoc)
+	for _, heredoc := range req.heredocs {
+		heredocLookup[heredoc.Name] = heredoc
+	}
+
+	var sourcePaths []string
+	var sourceContents []SourceContent
+	for _, src := range srcs {
+		if heredoc := parser.MustParseHeredoc(src); heredoc != nil {
+			content := heredocLookup[heredoc.Name].Content
+			if heredoc.Chomp {
+				content = parser.ChompHeredocContent(content)
+			}
+			sourceContents = append(sourceContents,
+				SourceContent{
+					Data:   content,
+					Path:   heredoc.Name,
+					Expand: heredoc.Expand,
+				},
+			)
+		} else {
+			sourcePaths = append(sourcePaths, src)
+		}
+	}
+
+	return &SourcesAndDest{
+		DestPath:       dest,
+		SourcePaths:    sourcePaths,
+		SourceContents: sourceContents,
+	}, nil
+}
+
 func parseAdd(req parseRequest) (*AddCommand, error) {
 	if len(req.args) < 2 {
 		return nil, errNoDestinationArgument("ADD")
@@ -245,9 +286,15 @@ func parseAdd(req parseRequest) (*AddCommand, error) {
 	if err := req.flags.Parse(); err != nil {
 		return nil, err
 	}
+
+	sourcesAndDest, err := parseSourcesAndDest(req, "ADD")
+	if err != nil {
+		return nil, err
+	}
+
 	return &AddCommand{
-		SourcesAndDest:  SourcesAndDest(req.args),
 		withNameAndCode: newWithNameAndCode(req),
+		SourcesAndDest:  *sourcesAndDest,
 		Chown:           flChown.Value,
 		Chmod:           flChmod.Value,
 	}, nil
@@ -263,10 +310,16 @@ func parseCopy(req parseRequest) (*CopyCommand, error) {
 	if err := req.flags.Parse(); err != nil {
 		return nil, err
 	}
+
+	sourcesAndDest, err := parseSourcesAndDest(req, "COPY")
+	if err != nil {
+		return nil, err
+	}
+
 	return &CopyCommand{
-		SourcesAndDest:  SourcesAndDest(req.args),
-		From:            flFrom.Value,
 		withNameAndCode: newWithNameAndCode(req),
+		SourcesAndDest:  *sourcesAndDest,
+		From:            flFrom.Value,
 		Chown:           flChown.Value,
 		Chmod:           flChmod.Value,
 	}, nil
@@ -351,7 +404,17 @@ func parseWorkdir(req parseRequest) (*WorkdirCommand, error) {
 
 }
 
-func parseShellDependentCommand(req parseRequest, emptyAsNil bool) ShellDependantCmdLine {
+func parseShellDependentCommand(req parseRequest, command string, emptyAsNil bool) (ShellDependantCmdLine, error) {
+	var files []ShellInlineFile
+	for _, heredoc := range req.heredocs {
+		file := ShellInlineFile{
+			Name:  heredoc.Name,
+			Data:  heredoc.Content,
+			Chomp: heredoc.Chomp,
+		}
+		files = append(files, file)
+	}
+
 	args := handleJSONArgs(req.args, req.attributes)
 	cmd := strslice.StrSlice(args)
 	if emptyAsNil && len(cmd) == 0 {
@@ -359,8 +422,9 @@ func parseShellDependentCommand(req parseRequest, emptyAsNil bool) ShellDependan
 	}
 	return ShellDependantCmdLine{
 		CmdLine:      cmd,
+		Files:        files,
 		PrependShell: !req.attributes["json"],
-	}
+	}, nil
 }
 
 func parseRun(req parseRequest) (*RunCommand, error) {
@@ -376,7 +440,13 @@ func parseRun(req parseRequest) (*RunCommand, error) {
 		return nil, err
 	}
 	cmd.FlagsUsed = req.flags.Used()
-	cmd.ShellDependantCmdLine = parseShellDependentCommand(req, false)
+
+	cmdline, err := parseShellDependentCommand(req, "RUN", false)
+	if err != nil {
+		return nil, err
+	}
+	cmd.ShellDependantCmdLine = cmdline
+
 	cmd.withNameAndCode = newWithNameAndCode(req)
 
 	for _, fn := range parseRunPostHooks {
@@ -392,11 +462,16 @@ func parseCmd(req parseRequest) (*CmdCommand, error) {
 	if err := req.flags.Parse(); err != nil {
 		return nil, err
 	}
+
+	cmdline, err := parseShellDependentCommand(req, "CMD", false)
+	if err != nil {
+		return nil, err
+	}
+
 	return &CmdCommand{
-		ShellDependantCmdLine: parseShellDependentCommand(req, false),
+		ShellDependantCmdLine: cmdline,
 		withNameAndCode:       newWithNameAndCode(req),
 	}, nil
-
 }
 
 func parseEntrypoint(req parseRequest) (*EntrypointCommand, error) {
@@ -404,12 +479,15 @@ func parseEntrypoint(req parseRequest) (*EntrypointCommand, error) {
 		return nil, err
 	}
 
-	cmd := &EntrypointCommand{
-		ShellDependantCmdLine: parseShellDependentCommand(req, true),
-		withNameAndCode:       newWithNameAndCode(req),
+	cmdline, err := parseShellDependentCommand(req, "ENTRYPOINT", true)
+	if err != nil {
+		return nil, err
 	}
 
-	return cmd, nil
+	return &EntrypointCommand{
+		ShellDependantCmdLine: cmdline,
+		withNameAndCode:       newWithNameAndCode(req),
+	}, nil
 }
 
 // parseOptInterval(flag) is the duration of flag.Value, or 0 if
@@ -651,6 +729,10 @@ func errNoDestinationArgument(command string) error {
 	return errors.Errorf("%s requires at least two arguments, but only one was provided. Destination could not be determined.", command)
 }
 
+func errBadHeredoc(command string, option string) error {
+	return errors.Errorf("%s cannot accept a heredoc as %s", command, option)
+}
+
 func errBlankCommandNames(command string) error {
 	return errors.Errorf("%s names can not be blank", command)
 }

frontend/dockerfile/instructions/parse_heredoc_test.go

@@ -0,0 +1,245 @@
+// +build dfheredoc
+
+package instructions
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/docker/docker/api/types/strslice"
+	"github.com/moby/buildkit/frontend/dockerfile/parser"
+	"github.com/stretchr/testify/require"
+)
+
+func TestErrorCasesHeredoc(t *testing.T) {
+	cases := []struct {
+		name          string
+		dockerfile    string
+		expectedError string
+	}{
+		{
+			name:          "COPY heredoc destination",
+			dockerfile:    "COPY /foo <<EOF\nEOF",
+			expectedError: "COPY cannot accept a heredoc as a destination",
+		},
+	}
+	for _, c := range cases {
+		r := strings.NewReader(c.dockerfile)
+		ast, err := parser.Parse(r)
+
+		if err != nil {
+			t.Fatalf("Error when parsing Dockerfile: %s", err)
+		}
+		n := ast.AST.Children[0]
+		_, err = ParseInstruction(n)
+		require.Error(t, err)
+		require.Contains(t, err.Error(), c.expectedError)
+	}
+}
+
+func TestCopyHeredoc(t *testing.T) {
+	cases := []struct {
+		dockerfile     string
+		sourcesAndDest SourcesAndDest
+	}{
+		{
+			dockerfile: "COPY /foo /bar",
+			sourcesAndDest: SourcesAndDest{
+				DestPath:    "/bar",
+				SourcePaths: []string{"/foo"},
+			},
+		},
+		{
+			dockerfile: `COPY <<EOF /bar
+EOF`,
+			sourcesAndDest: SourcesAndDest{
+				DestPath: "/bar",
+				SourceContents: []SourceContent{
+					{
+						Path:   "EOF",
+						Data:   "",
+						Expand: true,
+					},
+				},
+			},
+		},
+		{
+			dockerfile: `COPY <<EOF /bar
+TESTING
+EOF`,
+			sourcesAndDest: SourcesAndDest{
+				DestPath: "/bar",
+				SourceContents: []SourceContent{
+					{
+						Path:   "EOF",
+						Data:   "TESTING\n",
+						Expand: true,
+					},
+				},
+			},
+		},
+		{
+			dockerfile: `COPY <<-EOF /bar
+	TESTING
+EOF`,
+			sourcesAndDest: SourcesAndDest{
+				DestPath: "/bar",
+				SourceContents: []SourceContent{
+					{
+						Path:   "EOF",
+						Data:   "TESTING\n",
+						Expand: true,
+					},
+				},
+			},
+		},
+		{
+			dockerfile: `COPY <<'EOF' /bar
+TESTING
+EOF`,
+			sourcesAndDest: SourcesAndDest{
+				DestPath: "/bar",
+				SourceContents: []SourceContent{
+					{
+						Path:   "EOF",
+						Data:   "TESTING\n",
+						Expand: false,
+					},
+				},
+			},
+		},
+		{
+			dockerfile: `COPY <<EOF1 <<EOF2 /bar
+this is the first file
+EOF1
+this is the second file
+EOF2`,
+			sourcesAndDest: SourcesAndDest{
+				DestPath: "/bar",
+				SourceContents: []SourceContent{
+					{
+						Path:   "EOF1",
+						Data:   "this is the first file\n",
+						Expand: true,
+					},
+					{
+						Path:   "EOF2",
+						Data:   "this is the second file\n",
+						Expand: true,
+					},
+				},
+			},
+		},
+		{
+			dockerfile: `COPY <<EOF foo.txt /bar
+this is inline
+EOF`,
+			sourcesAndDest: SourcesAndDest{
+				DestPath:    "/bar",
+				SourcePaths: []string{"foo.txt"},
+				SourceContents: []SourceContent{
+					{
+						Path:   "EOF",
+						Data:   "this is inline\n",
+						Expand: true,
+					},
+				},
+			},
+		},
+	}
+
+	for _, c := range cases {
+		r := strings.NewReader(c.dockerfile)
+		ast, err := parser.Parse(r)
+		require.NoError(t, err)
+
+		n := ast.AST.Children[0]
+		comm, err := ParseInstruction(n)
+		require.NoError(t, err)
+
+		sd := comm.(*CopyCommand).SourcesAndDest
+		require.Equal(t, c.sourcesAndDest, sd)
+	}
+}
+
+func TestRunHeredoc(t *testing.T) {
+	cases := []struct {
+		dockerfile string
+		shell      bool
+		command    strslice.StrSlice
+		files      []ShellInlineFile
+	}{
+		{
+			dockerfile: `RUN ["ls", "/"]`,
+			command:    strslice.StrSlice{"ls", "/"},
+			shell:      false,
+		},
+		{
+			dockerfile: `RUN ["<<EOF"]`,
+			command:    strslice.StrSlice{"<<EOF"},
+			shell:      false,
+		},
+		{
+			dockerfile: "RUN ls /",
+			command:    strslice.StrSlice{"ls /"},
+			shell:      true,
+		},
+		{
+			dockerfile: `RUN <<EOF
+ls /
+whoami
+EOF`,
+			command: strslice.StrSlice{"<<EOF"},
+			files: []ShellInlineFile{
+				{
+					Name: "EOF",
+					Data: "ls /\nwhoami\n",
+				},
+			},
+			shell: true,
+		},
+		{
+			dockerfile: `RUN <<'EOF' | python
+print("hello")
+print("world")
+EOF`,
+			command: strslice.StrSlice{"<<'EOF' | python"},
+			files: []ShellInlineFile{
+				{
+					Name: "EOF",
+					Data: `print("hello")
+print("world")
+`,
+				},
+			},
+			shell: true,
+		},
+		{
+			dockerfile: `RUN <<-EOF
+	echo test
+EOF`,
+			command: strslice.StrSlice{"<<-EOF"},
+			files: []ShellInlineFile{
+				{
+					Name:  "EOF",
+					Data:  "\techo test\n",
+					Chomp: true,
+				},
+			},
+			shell: true,
+		},
+	}
+
+	for _, c := range cases {
+		r := strings.NewReader(c.dockerfile)
+		ast, err := parser.Parse(r)
+		require.NoError(t, err)
+
+		n := ast.AST.Children[0]
+		comm, err := ParseInstruction(n)
+		require.NoError(t, err)
+		require.Equal(t, c.shell, comm.(*RunCommand).PrependShell)
+		require.Equal(t, c.command, comm.(*RunCommand).CmdLine)
+		require.Equal(t, c.files, comm.(*RunCommand).Files)
+	}
+}

frontend/dockerfile/instructions/parse_test.go

@@ -192,11 +192,6 @@ func TestErrorCases(t *testing.T) {
 			dockerfile:    "ONBUILD FROM scratch",
 			expectedError: "FROM isn't allowed as an ONBUILD trigger",
 		},
-		{
-			name:          "ONBUILD forbidden MAINTAINER",
-			dockerfile:    "ONBUILD MAINTAINER docker.io",
-			expectedError: "MAINTAINER isn't allowed as an ONBUILD trigger",
-		},
 		{
 			name:          "MAINTAINER unknown flag",
 			dockerfile:    "MAINTAINER --boo joe@example.com",
@@ -212,6 +207,11 @@ func TestErrorCases(t *testing.T) {
 			dockerfile:    `foo bar`,
 			expectedError: "unknown instruction: FOO",
 		},
+		{
+			name:          "Invalid instruction",
+			dockerfile:    `foo bar`,
+			expectedError: "unknown instruction: FOO",
+		},
 	}
 	for _, c := range cases {
 		r := strings.NewReader(c.dockerfile)