Cannot open encrypted DB after writing with StreamWriter

[danielmai]

What version of Go are you using (go version)?

$ go version
go version go1.13.3 linux/amd64

What version of Badger are you using?

Badger v2.0.0

Does this issue reproduce with the latest master?

Yes (407e5bd)

What are the hardware specifications of the machine (RAM, OS, Disk)?

Ubuntu Linux

What did you do?

I'm using StreamWriter to write to badger with encryption enabled.

package main

import (
	"flag"
	"fmt"
	"log"

	"github.com/dgraph-io/badger/v2"
	"github.com/dgraph-io/badger/v2/pb"
)

var (
	encrypt = flag.Bool("encrypt", true, "Enable encryption")
)

func check(err error, msg string) {
	if err != nil {
		log.Fatalf("%s: %v\n", msg, err)
	}
}

func main() {
	flag.Parse()
	opts := badger.DefaultOptions("/tmp/badger-test")
	log.Printf("Using encryption: %v\n", *encrypt)
	if *encrypt {
		opts = opts.WithEncryptionKey([]byte("badgerkey16bytes"))
	}
	db, err := badger.Open(opts)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	key := []byte("mykey")
	value := []byte("myvalue")

	list := &pb.KVList{}
	list.Kv = append(list.Kv, &pb.KV{
		Key:     key,
		Value:   value,
		Version: 20,
	})
	fmt.Printf("%+v\n", list.Kv)

	sw := db.NewStreamWriter()
	check(sw.Prepare(), "Prepare failed")
	check(sw.Write(list), "Write failed")
	check(sw.Flush(), "Flush failed")

	var val string
	err = db.View(func(txn *badger.Txn) error {
		item, err := txn.Get(key)
		if err != nil {
			return err
		}
		return item.Value(func(b []byte) error { val = string(b); return nil })
	})
	check(err, "Error while retrieving key")
	fmt.Printf("Value: %s\n", val)
}

What did you expect to see?

Running the program once works. Running it a second time to re-open the existing encrypted DB gives an error. I expect to successfully open the DB the second time around.

What did you see instead?

After a second run, the DB fails to open with an error message related to protos:

2019/12/05 15:00:45 proto: illegal wireType 7

github.com/dgraph-io/badger/v2/y.Wrap
	/home/dmai/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.0/y/error.go:71
github.com/dgraph-io/badger/v2/y.Check
	/home/dmai/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.0/y/error.go:43
github.com/dgraph-io/badger/v2/table.(*Table).readIndex
	/home/dmai/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.0/table/table.go:349
github.com/dgraph-io/badger/v2/table.(*Table).initBiggestAndSmallest
	/home/dmai/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.0/table/table.go:260
github.com/dgraph-io/badger/v2/table.OpenTable
	/home/dmai/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.0/table/table.go:227
github.com/dgraph-io/badger/v2.newLevelsController.func1
	/home/dmai/go/pkg/mod/github.com/dgraph-io/badger/v2@v2.0.0/levels.go:162
runtime.goexit
	/usr/local/go/src/runtime/asm_amd64.s:1357

Doing this for several runs can give different error messages:

$ rm -r /tmp/badger-test; go run main.go; go run main.go
...
2019/12/05 15:02:15 proto: TableIndex: wiretype end group for non-group
$ rm -r /tmp/badger-test; go run main.go; go run main.go
...
2019/12/05 15:03:01 proto: TableIndex: illegal tag -483489005 (wire type 901633650128607389)
$ rm -r /tmp/badger-test; go run main.go; go run main.go
...
2019/12/05 15:03:13 proto: illegal wireType 6
$ rm -r /tmp/badger-test; go run main.go; go run main.go
...
2019/12/05 15:03:45 unexpected EOF

Additional notes

If encryption is enabled (run the sample program with --encrypt=false), then re-opening the DB works as expected.