Stacktrace is undefined in failed jobs

Created by: avermeil

Hi!

When jobs fail, the stacktrace field in the job hash in redis stays "undefined". It looks to me like this is the fault of a line in the lua script on line 404 of job.js, which overwrites the stacktrace field with a value coming from the argument context, which isn't defined when _moveToSet() is called by moveToFailed().

Since the stacktrace field is already set by _saveAttempt(), just commenting out the that line of the lua script seems to fix it:

//redis.call("HSET", KEYS[3], "stacktrace", ARGV[1])

But I might be missing something.

Any ideas on what is going on here?