RetentionJoin() could block if scanner never started

CHANGELOG.md

@@ -2,7 +2,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [1.1.0-rc1]
+## [Unreleased]
+### Fixed
+- Shutdown hang in retention scanner
+
+## [1.1.0-rc1] - 2016-03-04
 ### Added
 - Inbucket now builds with Go 1.5 or 1.6
 - Project can build & run inside a Docker container

smtpd/retention.go

@@ -133,8 +133,10 @@ func doRetentionScan(ds DataStore, maxAge time.Duration, sleep time.Duration) er
 
 // RetentionJoin does not retun until the retention scanner has shut down
 func RetentionJoin() {
-	select {
-	case _ = <-retentionShutdown:
+	if retentionShutdown != nil {
+		select {
+		case _ = <-retentionShutdown:
+		}
 	}
 }