Claim task part 1 - Solidity with minimal tests

[zguesmi]

VoucherHub contract needs to check that the "refund" request is legit:

1. Option1: check that msg.sender is a voucher created by the hub and put all deal/task verification in Voucher contract.
   a. Compute voucher address and check it contains code => Not valid as users can mint vouchers themselves.
   b. Store a mapping of vouchers created by VoucherHub.

2. Option2: check that the deal was sponsored by a valid voucher.
   a. Store a mapping of all sponsored deals of each voucher ins VoucherHub. => This requires duplicating voucher logic in the hub (check deal exists, check task status, ...).

=> Approach 1.a is the chosen option.

Tests & coverage:

[jeremyjams]

I propose to move mapping(bytes32 taskId => bool) _refundedTasks; to VoucherHub (for example in order to protect against double refund)

[zguesmi]

That way we need to move deal/task checking logic to the VoucherHub.

[jeremyjams]

Yes exactly!

[zguesmi]

I tend to not prefer this option, because:

• if we do that we need to put all the claim logic in the Hub (otherwise would not work) so there is not much left in the Voucher. Also since the sponsored amount is saved in the Voucher, we will
  • either be bouncing back and forth between the voucher and the hub (voucher.claim, hub.claimOnPoco, voucher.computeSponsoredAmount, hub.refund
  • or duplicate things (reading PoCo state)
• I am not sure we don't risk cheating the Hub if we don't store voucher addresses.
• The top up feature would probably benefit from the voucher list to make sure the voucher exists (not a very strong argument but it goes in the same direction).
• Design wise, I find it cleaner to not include PoCo logic in the Hub.

[gfournieriExec]

Well done

[jeremyjams]

Good thanks!