From 439ac243b41525add2f8f608b2f218b8d93cfe95 Mon Sep 17 00:00:00 2001
From: Jason Aten <jason.aten@molecula.com>
Date: Tue, 15 Sep 2020 15:50:50 -0500
Subject: [PATCH] don't panic if dbs is reopened under roaring only. fixes #843

---
 dbshard.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/dbshard.go b/dbshard.go
index 5584ba09e..b992671d5 100644
--- a/dbshard.go
+++ b/dbshard.go
@@ -405,7 +405,11 @@ func (per *DBPerShard) GetDBShard(index string, shard uint64, idx *Index) (dbs *
 	}
 	dbs, ok = dbi.Shard[shard]
 	if dbs != nil && dbs.closed {
-		panic(fmt.Sprintf("cannot retain closed dbs across holder ReOpen dbs='%p'", dbs))
+		if len(per.types) == 1 && per.types[0] == roaringTxn {
+			// roaring txn are nil/fake anyway. Don't freak out.
+		} else {
+			panic(fmt.Sprintf("cannot retain closed dbs across holder ReOpen dbs='%p'", dbs))
+		}
 	}
 	if !ok {
 		dbs = &DBShard{