sql indexer ipld cache - confirm quit

prevents negative waitgroup panic

indexer/database/sql/batch_tx.go

@@ -36,7 +36,7 @@ type BatchTx struct {
 	ctx              context.Context
 	dbtx             Tx
 	stm              string
-	quit             chan struct{}
+	quit             chan (chan<- struct{})
 	iplds            chan models.IPLDModel
 	ipldCache        models.IPLDBatch
 	removedCacheFlag *uint32
@@ -81,8 +81,9 @@ func (tx *BatchTx) cache() {
 			tx.ipldCache.Keys = append(tx.ipldCache.Keys, i.Key)
 			tx.ipldCache.Values = append(tx.ipldCache.Values, i.Data)
 			tx.cacheWg.Done()
-		case <-tx.quit:
+		case confirm := <-tx.quit:
 			tx.ipldCache = models.IPLDBatch{}
+			confirm <- struct{}{}
 			return
 		}
 	}

indexer/database/sql/indexer.go

@@ -129,7 +129,7 @@ func (sdi *StateDiffIndexer) PushBlock(block *types.Block, receipts types.Receip
 		BlockNumber:      block.Number().String(),
 		stm:              sdi.dbWriter.db.InsertIPLDsStm(),
 		iplds:            make(chan models.IPLDModel),
-		quit:             make(chan struct{}),
+		quit:             make(chan (chan<- struct{})),
 		ipldCache: models.IPLDBatch{
 			BlockNumbers: make([]string, 0, startingCacheCapacity),
 			Keys:         make([]string, 0, startingCacheCapacity),
@@ -139,7 +139,10 @@ func (sdi *StateDiffIndexer) PushBlock(block *types.Block, receipts types.Receip
 		// handle transaction commit or rollback for any return case
 		submit: func(self *BatchTx, err error) error {
 			defer func() {
+				confirm := make(chan struct{})
+				self.quit <- confirm
 				close(self.quit)
+				<-confirm
 				close(self.iplds)
 			}()
 			if p := recover(); p != nil {