fix data race when indexing empty batches and using reset

index/scorch/scorch.go

@@ -312,15 +312,17 @@ func (s *Scorch) Batch(batch *index.Batch) (err error) {
 
 	// FIXME could sort ids list concurrent with analysis?
 
-	go func() {
-		for _, doc := range batch.IndexOps {
-			if doc != nil {
-				aw := index.NewAnalysisWork(s, doc, resultChan)
-				// put the work on the queue
-				s.analysisQueue.Queue(aw)
+	if len(batch.IndexOps) > 0 {
+		go func() {
+			for _, doc := range batch.IndexOps {
+				if doc != nil {
+					aw := index.NewAnalysisWork(s, doc, resultChan)
+					// put the work on the queue
+					s.analysisQueue.Queue(aw)
+				}
 			}
-		}
-	}()
+		}()
+	}
 
 	// wait for analysis result
 	analysisResults := make([]*index.AnalysisResult, int(numUpdates))

index/upsidedown/upsidedown.go

@@ -810,15 +810,17 @@ func (udc *UpsideDownCouch) Batch(batch *index.Batch) (err error) {
 		}
 	}
 
-	go func() {
-		for _, doc := range batch.IndexOps {
-			if doc != nil {
-				aw := index.NewAnalysisWork(udc, doc, resultChan)
-				// put the work on the queue
-				udc.analysisQueue.Queue(aw)
+	if len(batch.IndexOps) > 0 {
+		go func() {
+			for _, doc := range batch.IndexOps {
+				if doc != nil {
+					aw := index.NewAnalysisWork(udc, doc, resultChan)
+					// put the work on the queue
+					udc.analysisQueue.Queue(aw)
+				}
 			}
-		}
-	}()
+		}()
+	}
 
 	// retrieve back index rows concurrent with analysis
 	docBackIndexRowErr := error(nil)

index_test.go

@@ -32,6 +32,7 @@ import (
 	"github.com/blevesearch/bleve/analysis/analyzer/keyword"
 	"github.com/blevesearch/bleve/document"
 	"github.com/blevesearch/bleve/index"
+	"github.com/blevesearch/bleve/index/store/boltdb"
 	"github.com/blevesearch/bleve/index/store/null"
 	"github.com/blevesearch/bleve/mapping"
 	"github.com/blevesearch/bleve/search"
@@ -2149,3 +2150,37 @@ func TestBug1096(t *testing.T) {
 		t.Fatalf("expected only 2 hits '9' and '90', got %v", res)
 	}
 }
+
+func TestDataRaceBug1092(t *testing.T) {
+	defer func() {
+		rerr := os.RemoveAll("testidx")
+		if rerr != nil {
+			t.Fatal(rerr)
+		}
+	}()
+
+	// use default mapping
+	mapping := NewIndexMapping()
+
+	var idx Index
+	idx, err = NewUsing("testidx", mapping, upsidedown.Name, boltdb.Name, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer func() {
+		cerr := idx.Close()
+		if cerr != nil {
+			t.Fatal(cerr)
+		}
+	}()
+
+	batch := idx.NewBatch()
+	for i := 0; i < 10; i++ {
+		err = idx.Batch(batch)
+		if err != nil {
+			t.Error(err)
+		}
+
+		batch.Reset()
+	}
+}