fix: panic in the main hierarchy

Signed-off-by: VihasMakwana <121151420+VihasMakwana@users.noreply.github.com>

Author: VihasMakwana

CHANGELOG/CHANGELOG-1.5.md

@@ -6,5 +6,6 @@
 - [Add support for data file size limit](https://github.com/etcd-io/bbolt/pull/929)
 - [Remove the unused txs list](https://github.com/etcd-io/bbolt/pull/973)
 - [Add option `NoStatistics` to make the statistics optional](https://github.com/etcd-io/bbolt/pull/977)
+- [Move panic handling from goroutine to the parent function](https://github.com/etcd-io/bbolt/pull/1153)
 
 <hr>

db.go

@@ -1253,13 +1253,16 @@ func (db *DB) freepages() []common.Pgid {
 	reachable := make(map[common.Pgid]*common.Page)
 	nofreed := make(map[common.Pgid]bool)
 	ech := make(chan error)
+
 	go func() {
-		for e := range ech {
-			panic(fmt.Sprintf("freepages: failed to get all reachable pages (%v)", e))
-		}
+		defer close(ech)
+		tx.recursivelyCheckBucket(&tx.root, reachable, nofreed, HexKVStringer(), ech)
 	}()
-	tx.recursivelyCheckBucket(&tx.root, reachable, nofreed, HexKVStringer(), ech)
-	close(ech)
+	// following for loop will exit once channel is closed in the above goroutine.
+	// we don't need to wait explictly with a waitgroup
+	for e := range ech {
+		panic(fmt.Sprintf("freepages: failed to get all reachable pages (%v)", e))
+	}
 
 	// TODO: If check bucket reported any corruptions (ech) we shouldn't proceed to freeing the pages.