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Support migrating from Maker CDPs #44

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Support migrating from Maker CDPs #44

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e593814
Initial implementation of Maker CDP migration without new unit tests
kevincheng96 Oct 26, 2022
082f548
Set up first passing unit tests for Maker integration
kevincheng96 Oct 27, 2022
42da5c5
Fix implementation for max repay for CDP; add more tests
kevincheng96 Oct 27, 2022
e2ef769
Update spec
kevincheng96 Oct 27, 2022
11d6fb9
Fix extra indent in spec
kevincheng96 Oct 27, 2022
d14c2d1
Require user to have permission to modify CDP; don't supply collatera…
kevincheng96 Oct 28, 2022
57e3735
Get rid of a local var to fix stack too deep when running coverage
kevincheng96 Oct 28, 2022
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88 changes: 70 additions & 18 deletions SPEC.md
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Original file line number Diff line number Diff line change
Expand Up @@ -170,7 +170,7 @@ This function describes the initialization process for this contract. We set the
* **WRITE IMMUTABLE** `aaveV2LendingPool = aaveV2LendingPool_`
* **WRITE IMMUTABLE** `cdpManager = cdpManager_`
* **WRITE IMMUTABLE** `daiJoin = daiJoin_`
* **WRITE IMMUTABLE** `dai = daiJoin_.gem()`
* **WRITE IMMUTABLE** `dai = daiJoin_.dai()`
* **WRITE IMMUTABLE** `uniswapLiquidityPool = uniswapLiquidityPool_`
* **WRITE IMMUTABLE** `isUniswapLiquidityPoolToken0 = uniswapLiquidityPool.token0() == baseToken`
* **REQUIRE** `isUniswapLiquidityPoolToken0 || uniswapLiquidityPool.token1() == baseToken`
Expand Down Expand Up @@ -224,7 +224,7 @@ Notes:
- **BIND** `user = msg.sender`
- **REQUIRE** `compoundV2Position.borrows.length == compoundV2Position.paths.length`
- **REQUIRE** `aaveV2Position.borrows.length == aaveV2Position.paths.length`
- **BIND** `data = abi.encode(MigrationCallbackData{user, flashAmount, compoundV2Position, aaveV2Position, makerPositions})`
- **BIND** `data = abi.encode(MigrationCallbackData{user, flashAmount, compoundV2Position, aaveV2Position, cdpPositions})`
- **CALL** `uniswapLiquidityPool.flash(address(this), isUniswapLiquidityPoolToken0 ? flashAmount : 0, isUniswapLiquidityPoolToken0 ? 0 : flashAmount, data)`
- **STORE** `inMigration -= 1`

Expand Down Expand Up @@ -273,8 +273,8 @@ This internal helper function repays the user’s borrow positions on Compound V

#### Inputs

- `address user`: Alias for the `msg.sender` of the original `migrate` call
- `compoundV2Position CompoundV2Position` - Structure containing the user’s Compound V2 collateral and borrow positions to migrate to Compound III.
- `user: address`: Alias for the `msg.sender` of the original `migrate` call
- `compoundV2Position: CompoundV2Position` - Structure containing the user’s Compound V2 collateral and borrow positions to migrate to Compound III.

#### Bindings

Expand Down Expand Up @@ -315,8 +315,8 @@ This internal helper function repays the user’s borrow positions on Aave V2 (e

#### Inputs

- `address user`: Alias for the `msg.sender` of the original `migrate` call
- `aaveV2Position AaveV2Position` - Structure containing the user’s Aave V2 collateral and borrow positions to migrate to Compound III.
- `user: address`: Alias for the `msg.sender` of the original `migrate` call
- `aaveV2Position: AaveV2Position` - Structure containing the user’s Aave V2 collateral and borrow positions to migrate to Compound III.

#### Bindings

Expand Down Expand Up @@ -353,41 +353,93 @@ This internal helper function repays the user’s borrow positions on Maker (exe

#### Inputs

- `address user`: Alias for the `msg.sender` of the original `migrate` call
- `cdpPositions CDPPosition[]` - List of structures that each represent a single CDP’s collateral and borrow position to migrate to Compound III.
- `user: address`: Alias for the `msg.sender` of the original `migrate` call
- `cdpPositions: CDPPosition[]` - List of structures that each represent a single CDP’s collateral and borrow position to migrate to Compound III.

#### Bindings

* `user: address`: Alias for `msg.sender`.
* `vat: VatLike`: The address of the core vault engine for Maker.
* `cdpOwner: address`: The owner of the CDP.
* `withdrawAmount: uint256`: The amount of collateral to withdraw.
* `withdrawAmount18: uint256`: The amount of collateral to withdraw, scaled up to 18 decimals.
* `repayAmount: uint256`: The amount to repay for each borrow position.
* `dart: int256`: The normalized amount to decrease a CDP’s debt by.
* `underlyingDebt: IERC20` - The underlying asset of an Aave debt token.
* `underlyingCollateral: IERC20` - The underlying asset of an Aave aToken. No special handling needed for ETH because Aave v2 uses WETH.

#### Function Spec

`function migrateCDPPositions(address user, CDPPosition[] positions) internal`
- **BIND READ** `vat = cdpManager.vat()`
- **FOREACH** `(cdpId, borrowAmount, collateralAmount, path, gemJoin): CDPPosition` in `positions`:
- **WHEN** `borrowAmount == type(uint256).max) || collateralAmount == type(uint256).max`:
- **BIND READ** `(withdrawAmount18, repayAmount) = cdpManager.vat().urns(cdpManager.ilks(cdpId), cdpManager.urns(cdpId))`
- **BIND** `withdrawAmount = withdrawAmount18 / (10 ** (18 - gemJoin.dec()))`
- **WHEN** `borrowAmount != type(uint256).max`
**BIND READ** `cdpOwner = cdpManager.owns(cdpId)`
**WHEN** `cdpOwner != user && cdpManager.cdpCan(cdpOwner, cdpId, user) == 0`:
- **REVERT** `UnauthorizedCDP(cdpId)`
- **WHEN** `borrowAmount == type(uint256).max`:
- **BIND READ** `repayAmount = getVaultDebt(vat, ilk, urn)`
- **BIND READ** `(, dart) = ​​-vat.urns(ilk, urn)`
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Is vat.urns guaranteed to be <= 0?

– **ELSE**
- **BIND** `repayAmount = borrowAmount`
- **WHEN** `collateralAmount != type(uint256).max`
- **BIND READ** `dart = getWipeDart(vat, repayAmount, urn, ilk)`
- **WHEN** `collateralAmount == type(uint256).max`:
- **BIND READ** `(withdrawAmount18,) = vat.urns(cdpManager.ilks(cdpId), cdpManager.urns(cdpId))`
- **BIND** `withdrawAmount = withdrawAmount18 / (10 ** (18 - gemJoin.dec()))`
- **ELSE**
- **BIND** `withdrawAmount = collateralAmount`
- **BIND** `withdrawAmount18 = collateralAmount * (10 ** (18 - gemJoin.dec()))`
- **WHEN** `path.length > 0`:
- **CALL** `ISwapRouter.exactOutput(ExactOutputParams({path: path, recipient: address(this), amountOut: repayAmount, amountInMaximum: type(uint256).max})`
- **CALL** `dai.approve(daiJoin, repayAmount)`
- **CALL** `daiJoin.join(cdpManager.urns(cdpId), repayAmount)`
- **CALL** `cdpManager.frob(cdpId, 0, -repayAmount)`
- **CALL** `cdpManager.frob(cdpId, -withdrawAmount18, 0)`
- **CALL** `cdpManager.frob(cdpId, -withdrawAmount18, dart)`
- **CALL** `cdpManager.flux(cdpId, address(this), withdrawAmount18)`
- **CALL** `gemJoin.exit(address(this), withdrawAmount)`
- **BIND READ** `underlyingCollateral = gemJoin.gem()`
- **CALL** `underlyingCollateral.approve(address(comet), type(uint256).max)`
- **CALL** `comet.supplyTo(user, underlying, underlying.balanceOf(address(this)))`
- **WHEN** `withdrawAmount != 0`:
- **BIND READ** `underlyingCollateral = gemJoin.gem()`
- **CALL** `underlyingCollateral.approve(address(comet), type(uint256).max)`
- **CALL** `comet.supplyTo(user, underlyingCollateral, underlyingCollateral.balanceOf(address(this)))`

### Get Maker CDP Debt Function

This internal helper function calculates the total unnormalized debt remaining in a vault.

#### Inputs

- `vat: VatLike`: The address of the core vault engine for Maker.
- `ilk: bytes32`: The collateral type for the vault.
- `urn: address`: The address of the vault.

#### Function Spec

`function getVaultDebt(VatLike vat, bytes32 ilk, address urn) internal returns (uint256)`
- **BIND READ** `rate = vat.ilks(ilk)`
- **BIND READ** `art = vat.urns(ilk, urn)`
- **BIND READ** `daiInUrn = vat.dai(urn)`
- **BIND** `rad = art * rate - daiInUrn`
- **BIND** `wad = rad / 10**27`
- **BIND** `wad * 10**27 < rad ? wad + 1 : wad`
- **RETURN** `wad`

### Get CDP Wipe Dart Function

This internal helper function calculates the normalized amount to decrease a vault's debt by.

#### Inputs

- `vat: VatLike`: The address of the core vault engine for Maker.
- `amount: uint256`: The actual unnormalized amount to decrease the debt by.
- `ilk: bytes32`: The collateral type for the vault.
- `urn: address`: The address of the vault.

#### Function Spec

`function getVaultDebt(VatLike vat, uint256 amount, address urn, bytes32 ilk) internal returns (int256)`
- **BIND READ** `rate = vat.ilks(ilk)`
- **BIND READ** `art = vat.urns(ilk, urn)`
- **BIND** `dart = amount * 10**27 / rate`
- **BIND** `dart = dart <= art ? -dart : -art`
- **RETURN** `dart`

### Sweep Function

Expand Down
2 changes: 2 additions & 0 deletions script/Playground.s.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,8 @@ contract Playground is Script, Test, MainnetConstants {
cETH,
weth,
aaveV2LendingPool,
cdpManager,
daiJoin,
pool_DAI_USDC,
swapRouter,
sweepee
Expand Down
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