dockerfile: additional expansions

rhel/dockerfile/dockerfile.go

@@ -100,9 +100,9 @@ func (p *labelParser) Run() error {
 			if strings.Contains(v, `escape=`) {
 				eq := strings.IndexByte(v, '=')
 				if eq == -1 {
-					return fmt.Errorf("botched parser directive: %#q", i.val)
+					panic("string changed while parsing?")
 				}
-				esc, _ := utf8.DecodeRuneInString(v[:eq+1])
+				esc, _ := utf8.DecodeRuneInString(v[eq+1:])
 				p.lex.Escape(esc)
 				p.unquote.Escape(esc)
 				p.vars.Escape(esc)

rhel/dockerfile/dockerfile_test.go

@@ -4,60 +4,56 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/fs"
-	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"golang.org/x/tools/txtar"
 )
 
 func TestGetLabels(t *testing.T) {
+	var errPrefix = []byte("error:")
 	ctx := context.Background()
-	td := os.DirFS("testdata")
-	de, err := fs.ReadDir(td, ".")
+
+	ms, err := filepath.Glob("testdata/*.txtar")
 	if err != nil {
 		t.Fatal(err)
 	}
-	for _, de := range de {
-		n := de.Name()
-		if !strings.HasPrefix(n, "Dockerfile") ||
-			strings.HasSuffix(n, ".want") ||
-			strings.HasSuffix(n, ".want.err") {
-			continue
-		}
-		t.Run(n, func(t *testing.T) {
-			f, err := td.Open(n)
+	for _, m := range ms {
+		t.Run(strings.TrimSuffix(filepath.Base(m), filepath.Ext(m)), func(t *testing.T) {
+			ar, err := txtar.ParseFile(m)
 			if err != nil {
-				t.Fatal(err)
+				t.Fatalf("error parsing archive: %v", err)
 			}
-			defer f.Close()
-			w, err := td.Open(n + ".want")
-			if err != nil {
-				t.Fatal(err)
-			}
-			defer w.Close()
-			wantErr, _ := fs.ReadFile(td, n+".want.err")
 
-			want := make(map[string]string)
-			if err := json.NewDecoder(w).Decode(&want); err != nil {
-				t.Error(err)
-			}
-			got, err := GetLabels(ctx, f)
-			if len(wantErr) == 0 {
-				if err != nil {
-					t.Error(err)
-				}
-			} else {
-				if err == nil {
-					t.Error("got nil, wanted error")
-				} else {
-					if got, want := err.Error(), string(bytes.TrimSpace(wantErr)); got != want {
-						t.Errorf("got: %+#q, want: %+#q", got, want)
+			var got, want map[string]string
+			wantErr := bytes.HasPrefix(ar.Comment, errPrefix)
+			for _, f := range ar.Files {
+				switch f.Name {
+				case "Dockerfile":
+					got, err = GetLabels(ctx, bytes.NewReader(f.Data))
+				case "Want":
+					want = make(map[string]string)
+					if err := json.Unmarshal(f.Data, &want); err != nil {
+						t.Fatalf("unmarshaling wanted values: %v", err)
 					}
+				default:
+					t.Logf("skipping unknown file: %s", f.Name)
 				}
 			}
 
+			if wantErr {
+				got := err.Error()
+				want := string(bytes.TrimSpace(bytes.TrimPrefix(ar.Comment, errPrefix)))
+				if got != want {
+					t.Error(cmp.Diff(got, want))
+				}
+				return
+			}
+			if err != nil {
+				t.Errorf("error parsing labels: %v", err)
+			}
 			if !cmp.Equal(got, want) {
 				t.Error(cmp.Diff(got, want))
 			}

rhel/dockerfile/fuzz_test.go

@@ -2,10 +2,31 @@ package dockerfile
 
 import (
 	"bytes"
+	"path/filepath"
 	"testing"
+
+	"golang.org/x/tools/txtar"
 )
 
 func FuzzLex(f *testing.F) {
+	ms, err := filepath.Glob("testdata/*.txtar")
+	if err != nil {
+		f.Fatal(err)
+	}
+	for _, m := range ms {
+		ar, err := txtar.ParseFile(m)
+		if err != nil {
+			f.Fatalf("error parsing archive: %v", err)
+		}
+	File:
+		for _, af := range ar.Files {
+			if af.Name == "Dockerfile" {
+				f.Add(af.Data)
+				break File
+			}
+		}
+	}
+
 	f.Fuzz(func(t *testing.T, b []byte) {
 		l := newLexer()
 		l.Reset(bytes.NewReader(b))
@@ -22,4 +43,6 @@ func FuzzLex(f *testing.F) {
 	})
 }
 
-//go:generate sh -c "go run golang.org/x/tools/cmd/file2fuzz -o testdata/fuzz/FuzzLex $(ls -1 testdata/Dockerfile* | grep -v [.]want)"
+// To add new files to the fuzz corpus:
+//
+//	go run golang.org/x/tools/cmd/file2fuzz -o testdata/fuzz/FuzzLex [FILE]

rhel/dockerfile/generate.go

@@ -0,0 +1,5 @@
+package dockerfile
+
+//go:generate -command stringer go run golang.org/x/tools/cmd/stringer
+//go:generate stringer -type itemKind
+//go:generate stringer -type varExpand -linecomment

rhel/dockerfile/lex.go

@@ -58,9 +58,6 @@ type item struct {
 
 type itemKind int
 
-//go:generate -command stringer go run golang.org/x/tools/cmd/stringer
-//go:generate stringer -type itemKind
-
 const (
 	itemError itemKind = iota
 	itemComment

rhel/dockerfile/testdata/Colon.txtar

@@ -0,0 +1,3 @@
+error: dockerfile: bad expansion of "error": rogue colon
+-- Dockerfile --
+LABEL a ${error::}

rhel/dockerfile/testdata/Dockerfile-Comments → rhel/dockerfile/testdata/Comments.txtar

@@ -1,3 +1,4 @@
+-- Dockerfile --
 # Normal comments are fine
 FROM scratch
 
@@ -7,3 +8,8 @@ LABEL \
 	C=D
 	# This comment is stripped despite the apparent continuation
 
+-- Want --
+{
+  "A": "B",
+  "C": "D"
+}

rhel/dockerfile/testdata/Default.txtar

@@ -0,0 +1,15 @@
+-- Dockerfile --
+LABEL a ${unset}
+LABEL b ${unset=set}
+LABEL c ${unset}
+
+LABEL null=
+LABEL d ${null:=reset}
+-- Want --
+{
+  "a": "",
+  "b": "set",
+  "c": "set",
+  "d": "reset",
+  "null": ""
+}

rhel/dockerfile/testdata/Error.txtar

@@ -0,0 +1,3 @@
+error: dockerfile: bad expansion of "unset": should error (error if unset or null)
+-- Dockerfile --
+LABEL a ${unset:?should error}

rhel/dockerfile/testdata/Escape.txtar

@@ -0,0 +1,8 @@
+-- Dockerfile --
+# escape=ꙮ
+LABEL a ꙮ
+ꙮ$b
+-- Want --
+{
+  "a": "$b"
+}

rhel/dockerfile/testdata/InvalidLabel.txtar

@@ -0,0 +1,4 @@
+error: invalid assignment syntax: `A=B 	C=D # Comments not allowed in this position`
+-- Dockerfile --
+LABEL A=B \
+	C=D # Comments not allowed in this position

rhel/dockerfile/testdata/Dockerfile-issue526 → rhel/dockerfile/testdata/Issue526.txtar

@@ -1,6 +1,11 @@
+-- Dockerfile --
 FROM scratch
 
 ENV A="B C" \
     D=E
 
 LABEL label="$A $D"
+-- Want --
+{
+  "label": "B C E"
+}