Fix incorrect double-dequeue after restarting (#12)

Author: izquierdo

queue_test.go

@@ -400,3 +400,32 @@ func TestQueueCorruptedWritingFile(t *testing.T) {
 	var e entry.Entry
 	require.False(t, q.Dequeue(&e))
 }
+
+func TestQueueReopen(t *testing.T) {
+	dataDir := filepath.Join(tmpDir, "pqueue_reopen")
+	_ = os.RemoveAll(dataDir)
+	err := os.MkdirAll(dataDir, 0o777)
+	require.NoError(t, err)
+	defer func() {
+		_ = os.RemoveAll(dataDir)
+	}()
+
+	q, err := New(dataDir, 3)
+	require.NoError(t, err)
+
+	require.NoError(t, q.Enqueue([]byte{1, 2, 3}))
+
+	var e entry.Entry
+	require.True(t, q.Dequeue(&e))
+	require.EqualValues(t, e, []byte{1, 2, 3})
+
+	err = q.Close()
+	require.NoError(t, err)
+
+	q, err = New(dataDir, 3)
+	require.NoError(t, err)
+
+	// only one value was enqueued and it was already dequeued, so there shouldn't be anything else
+	require.False(t, q.Dequeue(&e))
+	q.Close()
+}

utils.go

@@ -59,7 +59,7 @@ func loadFileInfos(dir string, infoExtractor func(os.DirEntry) (os.FileInfo, err
 
 	files := make([]file, 0, len(fileList))
 	for i := range fileList {
-		if strings.HasPrefix(fileList[i].Name(), segPrefix) {
+		if strings.HasPrefix(fileList[i].Name(), segPrefix) && !strings.HasSuffix(fileList[i].Name(), segOffsetFileSuffix) {
 			info, e := infoExtractor(fileList[i])
 			if e != nil {
 				return nil, e