fix: Handle panic when unpack info is missing (#117)

Author: bodgit

export_test.go

@@ -0,0 +1,3 @@
+package sevenzip
+
+var ErrMissingUnpackInfo = errMissingUnpackInfo

reader_test.go

@@ -47,6 +47,7 @@ func TestOpenReader(t *testing.T) {
 	tables := []struct {
 		name, file string
 		volumes    []string
+		err        error
 	}{
 		{
 			name: "no header compression",
@@ -140,6 +141,11 @@ func TestOpenReader(t *testing.T) {
 			name: "issue 87",
 			file: "issue87.7z",
 		},
+		{
+			name: "issue 113",
+			file: "COMPRESS-492.7z",
+			err:  sevenzip.ErrMissingUnpackInfo,
+		},
 	}
 
 	for _, table := range tables {
@@ -149,7 +155,9 @@ func TestOpenReader(t *testing.T) {
 			t.Parallel()
 			r, err := sevenzip.OpenReader(filepath.Join("testdata", table.file))
 			if err != nil {
-				t.Fatal(err)
+				assert.ErrorIs(t, err, table.err)
+
+				return
 			}
 			defer r.Close()
 

testdata/COMPRESS-492.7z

@@ -46,8 +46,9 @@ const (
 )
 
 var (
-	errIncompleteRead = errors.New("sevenzip: incomplete read")
-	errUnexpectedID   = errors.New("sevenzip: unexpected id")
+	errIncompleteRead    = errors.New("sevenzip: incomplete read")
+	errUnexpectedID      = errors.New("sevenzip: unexpected id")
+	errMissingUnpackInfo = errors.New("sevenzip: missing unpack info")
 )
 
 func readUint64(r io.ByteReader) (uint64, error) {
@@ -510,6 +511,10 @@ func readStreamsInfo(r util.Reader) (*streamsInfo, error) {
 	}
 
 	if id == idSubStreamsInfo {
+		if s.unpackInfo == nil {
+			return nil, errMissingUnpackInfo
+		}
+
 		if s.subStreamsInfo, err = readSubStreamsInfo(r, s.unpackInfo.folder); err != nil {
 			return nil, err
 		}