From 1cb7a86e37d579e9b23e9e5041ed03c5f5a3d4a5 Mon Sep 17 00:00:00 2001
From: Andrew Thornton <art27@cantab.net>
Date: Sat, 4 Jan 2020 15:26:18 +0000
Subject: [PATCH] Add warning if number of workers < 0

---
 modules/queue/workerpool.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/modules/queue/workerpool.go b/modules/queue/workerpool.go
index e92c1ec315..25fc7dd644 100644
--- a/modules/queue/workerpool.go
+++ b/modules/queue/workerpool.go
@@ -202,8 +202,11 @@ func (p *WorkerPool) addWorkers(ctx context.Context, number int) {
 
 			p.lock.Lock()
 			p.numberOfWorkers--
-			if p.numberOfWorkers <= 0 {
+			if p.numberOfWorkers == 0 {
+				p.cond.Broadcast()
+			} else if p.numberOfWorkers < 0 {
 				// numberOfWorkers can't go negative but...
+				log.Warn("Number of Workers < 0 for QID %d - this shouldn't happen", p.qid)
 				p.numberOfWorkers = 0
 				p.cond.Broadcast()
 			}