Add new tests using tar files from stdlib

entry.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"io/fs"
 	"sort"
+	"strings"
 	"time"
 )
 
@@ -155,7 +156,7 @@ type entriesByName []fs.DirEntry
 var _ sort.Interface = entriesByName{}
 
 func (entries entriesByName) Less(i, j int) bool {
-	return entries[i].Name() < entries[j].Name()
+	return strings.Compare(entries[i].Name(), entries[j].Name()) < 0
 }
 
 func (entries entriesByName) Len() int {

fs.go

@@ -7,6 +7,7 @@ import (
 	"io/fs"
 	"path"
 	"strings"
+	"unicode/utf8"
 )
 
 const (
@@ -180,7 +181,7 @@ func (tfs *tarfs) Sub(dir string) (fs.FS, error) {
 }
 
 func (tfs *tarfs) get(op, path string) (entry, error) {
-	if !fs.ValidPath(path) {
+	if !fs.ValidPath(path) && utf8.ValidString(path) {
 		return nil, newErr(op, path, fs.ErrInvalid)
 	}
 

fs_test.go

@@ -4,6 +4,8 @@ import (
 	"io"
 	"io/fs"
 	"os"
+	"path/filepath"
+	"runtime"
 	"testing"
 	"testing/fstest"
 
@@ -429,3 +431,45 @@ func TestIgnoreGlobalHeader(t *testing.T) {
 	err = fstest.TestFS(tfs, "bar", "dir1", "dir1/file11")
 	require.NoError(err)
 }
+
+func TestVariousTarTypes(t *testing.T) {
+	assert := assert.New(t)
+
+	for _, file := range []struct {
+		path      string
+		expecteds []string
+	}{
+		{"file-and-dir.tar", []string{"small.txt"}},
+		{"gnu.tar", []string{"small.txt", "small2.txt"}},
+		// {"gnu-incremental.tar", []string{"test2/foo", "test2/sparse"}},
+		{"gnu-long-nul.tar", []string{"0123456789"}},
+		{"gnu-multi-hdrs.tar", []string{"GNU2/GNU2/long-path-name"}},
+		{"gnu-nil-sparse-data.tar", []string{"sparse.db"}},
+		{"gnu-nil-sparse-hole.tar", []string{"sparse.db"}},
+		{"gnu-not-utf8.tar", []string{"hi\200\201\202\203bye"}},
+		// gnu-sparse-big.tar: too big
+		{"gnu-utf8.tar", []string{"☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹"}},
+		{"hardlink.tar", []string{"file.txt", "hard.txt"}},
+		// {"hdr-only.tar", []string{"file"}},
+	} {
+		func() {
+			f, err := os.Open(filepath.Join(runtime.GOROOT(), "src/archive/tar/testdata", file.path))
+			if !assert.NoError(err) {
+				return
+			}
+			defer f.Close()
+
+			tfs, err := New(f)
+			if !assert.NoError(err) {
+				return
+			}
+			assert.NoError(err)
+
+			err = fstest.TestFS(tfs, file.expecteds...)
+			if !assert.NoError(err) {
+				return
+			}
+			assert.NoError(err)
+		}()
+	}
+}