LockstakeClipper Callee

[valiafetisov]

This PR implements callee contract for the LockstakeClipper using UniswapV2. It allows anyone to participate in auctions using UniswapV2 path to exchange MKR (or NGT) into DAI (or NST).

Notes:

• CI is expected to fail due to the tests for other callees being fragile / depending on the market
  • To test this specific callee, one can run forge test --match-contract=UniswapV2LockstakeCalleeTest locally
• In order to write tests for the new callee, we had to update dependencies and remove hardcoded solidity version at the foundry level (--use solc:0.6.12) while strictly setting it in every callee contract instead. This is due to LockstakeEngine requiring at least 0.8.21 solidity version
  • If requested, those changes could be moved into a separate maintenance PR to keep git history clean
• Current version of the callee support any UniV2 paths that start from MKR or NGT and end with DAI or NST (in other words both MKR/DAI and NGT/NST pools are supported, but not only). The previous version of the callee (found at 9b5cb11) required a redeployment to support different destination token
  • Please let us know which contract design is preferable

[DaiFoundation-DevOps]

All committers have signed the CLA.

[oldchili]

Only looked at the new callee contract, looks good.
Made some minor comments.

[oldchili]

All changes look good, I'm not able to resolve the comments, so please do that on your side.

[DaeunYoon]

All comments are addressed and the changes look good to me.
Feel free to resolve the above comments as I'm not able to do it.

[SidestreamIcedMango]

• Checked callee contract
  • Static Interfaces
    • No unused static interfaces
    • Interface naming style should match with Like suffix (e.g. VatLike)
      • EXCEPTION: known interface naming exceptions
    • Each static interface declare only functions actually used in the spell code
  • Precision units
    • Precision units match their defined values:
      • WAD = 10 ** 18
      • RAY = 10 ** 27
      • RAD = 10 ** 45
    • Precision units match with Numerical Ranges
  • Ensure every variable is declared as public/internal
• Checked tests
  • Ensure solc version is matching with contract
  • Checked MockUniswapRouter02
    • Simulates UniswapV2Router02 deployed at 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
      • address found in the uniswap docs
    • Interface for function swapExactTokensForTokens matches
    • Behaviour of the function is correctly mocked
  • Checked UniswapV2LockstakeCalleeTest
    • Function setUp matches with provided existing test function
    • Function _urnSetUp matches with provided existing test function
    • Function _forceLiquidation matches with provided existing test function
    • Checked setUpCallee
      • Correctly sets up test callee
    • Checked _testCalleeTake
      • Simulates and tests multiple actors using the callee to take from an auction
  • Test calls cover all relevant cases
• Checked formatting
• Check all tests are passing locally using make test

Ran 16 tests for src/test/UniswapV2LockstakeCallee.t.sol:UniswapV2LockstakeCalleeTest
[PASS] testCalleeTake_NoDelegate_NoStaking_MkrDai() (gas: 3476105)
[PASS] testCalleeTake_NoDelegate_NoStaking_MkrNst() (gas: 3401278)
[PASS] testCalleeTake_NoDelegate_NoStaking_NgtDai() (gas: 3576068)
[PASS] testCalleeTake_NoDelegate_NoStaking_NgtNst() (gas: 3501285)
[PASS] testCalleeTake_NoDelegate_WithStaking_MkrDai() (gas: 3515101)
[PASS] testCalleeTake_NoDelegate_WithStaking_MkrNst() (gas: 3440273)
[PASS] testCalleeTake_NoDelegate_WithStaking_NgtDai() (gas: 3615082)
[PASS] testCalleeTake_NoDelegate_WithStaking_NgtNst() (gas: 3540253)
[PASS] testCalleeTake_WithDelegate_NoStaking_MkrDai() (gas: 3513726)
[PASS] testCalleeTake_WithDelegate_NoStaking_MkrNst() (gas: 3438942)
[PASS] testCalleeTake_WithDelegate_NoStaking_NgtDai() (gas: 3613688)
[PASS] testCalleeTake_WithDelegate_NoStaking_NgtNst() (gas: 3538862)
[PASS] testCalleeTake_WithDelegate_WithStaking_MkrDai() (gas: 3552697)
[PASS] testCalleeTake_WithDelegate_WithStaking_MkrNst() (gas: 3477869)
[PASS] testCalleeTake_WithDelegate_WithStaking_NgtDai() (gas: 3654092)
[PASS] testCalleeTake_WithDelegate_WithStaking_NgtNst() (gas: 3612389)
Suite result: ok. 16 passed; 0 failed; 0 skipped; finished in 50.59s (52.86s CPU time)