Merge pull request #963 from go-kivik/bug929

Fix bug 929

couchdb/client.go

@@ -125,7 +125,7 @@ func (p *updatesParser) parseMeta(i interface{}, dec *json.Decoder, key string)
  return meta.parseMeta(key, dec)
 }
 
-func newUpdates(ctx context.Context, r io.ReadCloser) (*couchUpdates, error) {
+func newUpdates(ctx context.Context, r io.ReadCloser) (driver.DBUpdates, error) {
  r, feedType, err := updatesFeedType(r)
  if err != nil {
  return nil, &internal.Error{Status: http.StatusBadGateway, Err: err}
@@ -136,6 +136,8 @@ func newUpdates(ctx context.Context, r io.ReadCloser) (*couchUpdates, error) {
  return newContinuousUpdates(ctx, r), nil
  case feedTypeNormal:
  return newNormalUpdates(ctx, r), nil
+ case feedTypeEmpty:
+ return newEmptyUpdates(r)
  }
  panic("unknown") // TODO: test
 }
@@ -145,6 +147,7 @@ type feedType int
 const (
  feedTypeNormal feedType = iota
  feedTypeContinuous
+ feedTypeEmpty
 )
 
 // updatesFeedType detects the type of Updates Feed (continuous, or normal) by
@@ -183,6 +186,8 @@ func updatesFeedType(r io.ReadCloser) (io.ReadCloser, feedType, error) {
  return r, feedTypeContinuous, nil
  case "results": // Normal feed
  return r, feedTypeNormal, nil
+ case "last_seq": // Normal feed, but with no results
+ return r, feedTypeEmpty, nil
  default: // Something unexpected
  return nil, 0, fmt.Errorf("kivik: unexpected JSON token %q in feed response, expected `db_name` or `results`", tok)
  }
@@ -202,6 +207,27 @@ func newContinuousUpdates(ctx context.Context, r io.ReadCloser) *couchUpdates {
  }
 }
 
+func newEmptyUpdates(r io.ReadCloser) (driver.DBUpdates, error) {
+ var updates emptyUpdates
+ if err := json.NewDecoder(r).Decode(&updates); err != nil {
+ return nil, err
+ }
+ return &updates, nil
+}
+
+type emptyUpdates struct {
+ Lastseq string `json:"last_seq"`
+}
+
+var (
+ _ driver.DBUpdates = (*emptyUpdates)(nil)
+ _ driver.LastSeqer = (*emptyUpdates)(nil)
+)
+
+func (u *emptyUpdates) Close() error { return nil }
+func (u *emptyUpdates) Next(*driver.DBUpdate) error { return io.EOF }
+func (u *emptyUpdates) LastSeq() (string, error) { return u.Lastseq, nil }
+
 func (u *couchUpdates) Next(update *driver.DBUpdate) error {
  return u.iter.next(update)
 }

couchdb/client_test.go

@@ -383,6 +383,18 @@ func TestDBUpdates(t *testing.T) {
  wantStatus: http.StatusBadRequest,
  wantErr: "eventsource feed type not supported",
  },
+ {
+ // Based on CI test failures, presumably from a race condition that
+ // causes the query to happen before any database is created.
+ name: "no databases",
+ client: newTestClient(&http.Response{
+ StatusCode: 200,
+ Header: http.Header{
+ "Content-Type": {"application/json"},
+ },
+ Body: Body(`{"last_seq":"38-g1AAAACLeJzLYWBgYMpgTmHgzcvPy09JdcjLz8gvLskBCScyJNX___8_K4M5UTgXKMBuZmFmYWFgjq4Yh_Y8FiDJ0ACk_qOYYpyanGiQYoquJwsAM_UqgA"}`),
+ }, nil),
+ },
  }
  for _, tt := range tests {
  t.Run(tt.name, func(t *testing.T) {
@@ -397,9 +409,6 @@ func TestDBUpdates(t *testing.T) {
  if err != nil {
  return
  }
- if _, ok := result.(*couchUpdates); !ok {
- t.Errorf("Unexpected type returned: %t", result)
- }
 
  var got []driver.DBUpdate
  for {
@@ -420,7 +429,7 @@ func TestDBUpdates(t *testing.T) {
  }
 }
 
-func newTestUpdates(t *testing.T, body io.ReadCloser) *couchUpdates {
+func newTestUpdates(t *testing.T, body io.ReadCloser) driver.DBUpdates {
  t.Helper()
  u, err := newUpdates(context.Background(), body)
  if err != nil {
@@ -433,7 +442,7 @@ func TestUpdatesNext(t *testing.T) {
  t.Parallel()
  tests := []struct {
  name string
- updates *couchUpdates
+ updates driver.DBUpdates
  status int
  err string
  expected *driver.DBUpdate