rewrite payday

[chadwhitacre]

Part of #3399.

[chadwhitacre]

I've printed out payday.py and started combing through it. The reason why #3399 (comment) doesn't result in escrow or complicated graph settling is that it ... doesn't do complicated graph settling: b can't feed their $1 back into the system. I think we should run with that, so that we can move towards #1383 with this.

[chadwhitacre]

I'm hoping we can also pick off #3378 while we're here, another part of #1383.

[chadwhitacre]

I believe since we're not cycling the graph multiple times per payday, we don't need to use the is_funded mechanism for distributing funds. We should just be able to use card_hold_ok directly.

[chadwhitacre]

Basically, the work here is to implement the prototype I wrote in Python, in the SQL inside prepare_db. Most of the Python shell around payday should be able to stay intact.

[chadwhitacre]

I'm starting with the test_transfer_tips{_whole_graph} tests, because that calls settle_tip_graph(), which is the heart of payday.

[chadwhitacre]

There is some interaction between participants.balance and payday_participants.card_hold_ok that I need to understand. It relates to #1383 and how we're going to approach that here.

[chadwhitacre]

On the one hand it seems like we should avoid tackling the arrears issue (#3378) on this PR. On the other hand ...

[chadwhitacre]

Okay! I believe with that last commit we've gotten rid of the feedback. 🎤 😵 screeeeeeeeeeeeee

Now to introduce teams ...

[chadwhitacre]

P.S. We still make payments from preexisting balances, which means we can avoid tackling #3378 here. Phew.

[chadwhitacre]

Wow. Caching is a 🐰-hole. I'm going to stub it out for now. We'll migrate caching of receiving, etc., later.

[chadwhitacre]

I'm also going to not worry about the payroll side this week. Gratipay is the only one of the half-dozen or so teams we're aiming to run with today that uses payroll. We'll just let the full amount clear to our bank account this week. Sorry, Gratipay team. :-/

[chadwhitacre]

I believe that's it for this PR.

[chadwhitacre]

Alright, Travis is green. ✅

Here we go! Nothing ventured, nothing gained!

[rohitpaulk]

👯