Cleans up dangerous function default variables ([] and {})

[sklarsa]

Description

Changes function default variables {} -> dict() and [] -> list()

Motivation and Context

Just cleaning up some of the errors from https://landscape.io/github/spotify/luigi/1347/messages/error

Have you tested this? If so, how?

Ran tox -e py27-nonhdfs and everything passes

[dlstadther]

Thanks @sklarsa ! The errors here are waiting on #2274 for resolution

[sklarsa]

Sounds good. Let me know if you need anything else from my end

[dlstadther]

Thanks @sklarsa !

[jhorman]

Isn't this still dangerous. The default args are still mutable. Isn't the right approach to set these to None, and default in code.

[kwilcox]

Correct @jhorman, this did not fix what was intended. However, I took a quick look and none of the mutable arguments are changed within the functions. It would be better to default these to None and set the defaults accordingly inside of the function as you mentioned but this shouldn't be causing any issues as is.

[Tarrasch]

@sklarsa, can you please send a new PR fixing this as @jhorman pointed out?

[sklarsa]

Yep I'll have one out this week

…

On Tue, Dec 5, 2017 at 10:41 AM, Arash Rouhani ***@***.***> wrote: @sklarsa <https://github.com/sklarsa>, can you please send a new PR fixing this as @jhorman <https://github.com/jhorman> pointed out? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2275 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB1xRXvkcVRbeyKiH5DiHxKMft2rfeEmks5s9WQmgaJpZM4QQYp_> .