another batch data race #1149
Description
Another corner case can lead to a race when resetting a batch, in this case it happens when batch just contains a delete (or more likely as it was found in the wild, when a batch contains ONLY deletes)
Here is the race with scorch:
=== RUN TestBatchRaceBugXXX
==================
WARNING: DATA RACE
Write at 0x00c0003484a0 by goroutine 10:
github.com/blevesearch/bleve.TestBatchRaceBugXXX()
/home/mschoch/dev/go/src/github.com/blevesearch/bleve/index/index.go:310 +0x320
testing.tRunner()
/usr/local/go/src/testing/testing.go:827 +0x162
Previous read at 0x00c0003484a0 by goroutine 15:
github.com/blevesearch/bleve/index/scorch.(*Scorch).Batch.func2()
/home/mschoch/dev/go/src/github.com/blevesearch/bleve/index/scorch/scorch.go:317 +0x52
Similar observation with upsidedown:
=== RUN TestBatchRaceBugXXX
==================
WARNING: DATA RACE
Write at 0x00c000352440 by goroutine 10:
github.com/blevesearch/bleve.TestBatchRaceBugXXX()
/home/mschoch/dev/go/src/github.com/blevesearch/bleve/index/index.go:310 +0x2dc
testing.tRunner()
/usr/local/go/src/testing/testing.go:827 +0x162
Previous read at 0x00c000352440 by goroutine 11:
github.com/blevesearch/bleve/index/upsidedown.(*UpsideDownCouch).Batch.func1()
/home/mschoch/dev/go/src/github.com/blevesearch/bleve/index/upsidedown/upsidedown.go:815 +0x52
The code to reproduce is:
func TestBatchRaceBugXXX(t *testing.T) {
defer func() {
err := os.RemoveAll("testidx")
if err != nil {
t.Fatal(err)
}
}()
//i, err := New("testidx", NewIndexMapping())
i, err := NewUsing("testidx", NewIndexMapping(), "scorch", "scorch", nil)
if err != nil {
t.Fatal(err)
}
defer func() {
err := i.Close()
if err != nil {
t.Fatal(err)
}
}()
b := i.NewBatch()
b.Delete("1")
err = i.Batch(b)
if err != nil {
t.Fatal(err)
}
b.Reset()
err = i.Batch(b)
if err != nil {
t.Fatal(err)
}
b.Reset()
}