YearnV2YieldSource save gas with pre-approval

[code423n4]

Handle

cmichel

Vulnerability details

YearnV2YieldSource._depositInVault can save gas by caching token in memory instead of accessing it 3 times from storage.

[asselstine]

We considered this, but it's possible for a malicious user to "drain" the approval of the contract, so there would need to be checks to see if approval dropped below a certain level. We opted to leave out the complexity.

[asselstine]

Actually, we'll tackle this. We will:

1. approve max on init
2. provide a function to approve max again

[kamescg]

• https://github.com/pooltogether/pooltogether-yearnv2-yield-source/pull/new/fix/95
• Fix/95 jmonteer/pooltogether-yearnv2-yield-source#5