fix: unlock job when moving it to delayed (#2329)

lib/commands/moveToDelayed-3.lua

@@ -1,7 +1,7 @@
 --[[
   Moves job from active to delayed set.
 
-  Input: 
+  Input:
     KEYS[1] active key
     KEYS[2] delayed key
     KEYS[3] job key
@@ -21,21 +21,27 @@
 local rcall = redis.call
 
 if rcall("EXISTS", KEYS[3]) == 1 then
+  local lockKey
+  local lock
 
   -- Check for job lock
   if ARGV[3] ~= "0" then
-    local lockKey = KEYS[3] .. ':lock'
-    local lock = rcall("GET", lockKey)
+    lockKey = KEYS[3] .. ':lock'
+    lock = rcall("GET", lockKey)
     if lock ~= ARGV[3] then
       return -2
     end
   end
-  
+
   local score = tonumber(ARGV[1])
   rcall("ZADD", KEYS[2], score, ARGV[2])
   rcall("PUBLISH", KEYS[2], (score / 0x1000))
   rcall("LREM", KEYS[1], 0, ARGV[2])
 
+  if lock then
+    rcall("DEL", lockKey)
+  end
+
   return 0
 else
   return -1

test/test_job.js

@@ -641,6 +641,28 @@ describe('Job', () => {
       });
     });
 
+    it('unlocks the job when moving it to delayed', () => {
+      queue.process(() => {
+        throw new Error('Oh dear');
+      });
+      return Job.create(
+        queue,
+        { foo: 'bar' },
+        { attempts: 3, backoff: 100 }
+      ).then(job => {
+        return new Promise(resolve => {
+          queue.once('failed', resolve);
+        })
+          .then(() => {
+            const client = new redis();
+            return client.get(job.lockKey());
+          })
+          .then(lockValue => {
+            expect(lockValue).to.be(null);
+          });
+      });
+    });
+
     it('marks the job as failed when attempts made equal to attempts given', () => {
       return Job.create(queue, { foo: 'bar' }, { attempts: 1 }).then(job => {
         return job