memdocstore: slice field breaks localfile

main.go

package main

import (
	"context"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"path/filepath"
	"time"

	"gocloud.dev/docstore"
	"gocloud.dev/docstore/memdocstore"
)

type Doc struct {
	Key   string `docstore:"keyField"`
	Array []int  `docstore:"array,omitempty"`

	DocstoreRevision interface{}
}

func main() {
	ctx := context.Background()

	tmpdir, err := ioutil.TempDir("", "docstoretest")
	if err != nil {
		log.Fatalf("failed to create tmpdir: %s\n", err)
	}
	tmpfile := filepath.Join(tmpdir, "coll")
	log.Printf("tmpfile: %s\n", tmpfile)
	log.Println("")

	log.Println("create without array")
	log.Println("====================")
	{
		d := &Doc{Key: fmt.Sprintf("%s", time.Now())}
		coll, err := open(tmpfile)
		if err != nil {
			log.Fatalf("failed to open collection before create: %s\n", err)
		}
		log.Println("open")

		err = coll.Create(ctx, d)
		if err != nil {
			log.Fatalf("failed to create doc: %s\n", err)
		}
		log.Println("create")

		coll.Close()
		log.Println("close")

		coll, err = open(tmpfile)
		if err != nil {
			log.Fatalf("failed to open collection after create: %s\n", err)
		}
		log.Println("open")

		log.Println("listing")
		list(ctx, coll)
		coll.Close()
		log.Println("close")
		log.Println("")
	}

	log.Println("create with array")
	log.Println("=================")
	{
		d := &Doc{Key: fmt.Sprintf("%s", time.Now()), Array: []int{1}}
		coll, err := open(tmpfile)
		if err != nil {
			log.Fatalf("failed to open collection before create: %s\n", err)
		}
		log.Println("open")

		err = coll.Create(ctx, d)
		if err != nil {
			log.Fatalf("failed to create doc: %s\n", err)
		}
		log.Println("create")

		coll.Close()
		log.Println("close")

		coll, err = open(tmpfile)
		if err != nil {
			log.Fatalf("failed to open collection after create: %s\n", err)
		}
		log.Println("open")

		log.Println("listing")
		list(ctx, coll)
		coll.Close()
		log.Println("close")
		log.Println("")
	}
}

func open(f string) (*docstore.Collection, error) {
	return memdocstore.OpenCollection("keyField", &memdocstore.Options{
		Filename: f,
	})
}

func list(ctx context.Context, coll *docstore.Collection) {
	iter := coll.Query().Get(ctx)
	defer iter.Stop()

	for {
		var d Doc
		err := iter.Next(ctx, &d)
		if err == io.EOF {
			break
		} else if err != nil {
			log.Println(err)
			return
		} else {
			log.Printf("- %#v\n", d)
		}
	}
}

output

2019/09/13 18:52:16 tmpfile: /var/folders/_j/zj04k0f94f73l_bxhjwtr07c0000gn/T/docstoretest913445769/coll
2019/09/13 18:52:16 
2019/09/13 18:52:16 create without array
2019/09/13 18:52:16 ====================
2019/09/13 18:52:16 open
2019/09/13 18:52:16 create
2019/09/13 18:52:16 close
2019/09/13 18:52:16 open
2019/09/13 18:52:16 listing
2019/09/13 18:52:16 - main.Doc{Key:"2019-09-13 18:52:16.537114 +0900 JST m=+0.004645387", Array:[]int(nil), DocstoreRevision:1}
2019/09/13 18:52:16 close
2019/09/13 18:52:16 
2019/09/13 18:52:16 create with array
2019/09/13 18:52:16 =================
2019/09/13 18:52:16 open
2019/09/13 18:52:16 create
2019/09/13 18:52:16 close
2019/09/13 18:52:16 failed to open collection after create: EOF
exit status 1