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Merge pull request #158 from liquity/stash_sp_rewards
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Optional claim/stash SP ETH rewards
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@RickGriff
RickGriff authored May 9, 2024
2 parents 76ab174 + ab29edd commit 963df88
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Showing 17 changed files with 1,237 additions and 526 deletions.
10 changes: 7 additions & 3 deletions contracts/src/Interfaces/IStabilityPool.sol
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Expand Up @@ -52,16 +52,18 @@ interface IStabilityPool is ILiquityBase {
* - Increases deposit, and takes new snapshots of accumulators P and S
* - Sends depositor's accumulated ETH gains to depositor
*/
function provideToSP(uint256 _amount) external;
function provideToSP(uint256 _amount, bool _doClaim) external;

/* withdrawFromSP():
* - Calculates depositor's ETH gain
* - Calculates the compounded deposit
* - Sends the requested BOLD withdrawal to depositor
* - Sends the requested BOLD withdrawal to depositor
* - (If _amount > userDeposit, the user withdraws all of their compounded deposit)
* - Decreases deposit by withdrawn amount and takes new snapshots of accumulators P and S
*/
function withdrawFromSP(uint256 _amount) external;
function withdrawFromSP(uint256 _amount, bool doClaim) external;

function claimAllETHGains() external;

/*
* Initial checks:
Expand All @@ -73,6 +75,8 @@ interface IStabilityPool is ILiquityBase {
*/
function offset(uint256 _debt, uint256 _coll) external;

function stashedETH(address _depositor) external view returns (uint256);

/*
* Returns the total amount of ETH held by the pool, accounted in an internal variable instead of `balance`,
* to exclude edge cases like ETH received from a self-destruct.
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78 changes: 63 additions & 15 deletions contracts/src/StabilityPool.sol
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Expand Up @@ -69,9 +69,9 @@ import "./Dependencies/CheckContract.sol";
* So, to track P accurately, we use a scale factor: if a liquidation would cause P to decrease to <1e-9 (and be rounded to 0 by Solidity),
* we first multiply P by 1e9, and increment a currentScale factor by 1.
*
* The added benefit of using 1e9 for the scale factor (rather than 1e18) is that it ensures negligible precision loss close to the
* scale boundary: when P is at its minimum value of 1e9, the relative precision loss in P due to floor division is only on the
* order of 1e-9.
* The added benefit of using 1e9 for the scale factor (rather than 1e18) is that it ensures negligible precision loss close to the
* scale boundary: when P is at its minimum value of 1e9, the relative precision loss in P due to floor division is only on the
* order of 1e-9.
*
* --- EPOCHS ---
*
Expand Down Expand Up @@ -163,6 +163,7 @@ contract StabilityPool is LiquityBase, Ownable, CheckContract, IStabilityPool {

mapping(address => Deposit) public deposits; // depositor address -> Deposit struct
mapping(address => Snapshots) public depositSnapshots; // depositor address -> snapshots struct
mapping(address => uint256) public stashedETH;

/* Product 'P': Running product by which to multiply an initial deposit, in order to find the current compounded deposit,
* after a series of liquidations have occurred, each of which cancel some Bold debt with the deposit.
Expand Down Expand Up @@ -280,14 +281,14 @@ contract StabilityPool is LiquityBase, Ownable, CheckContract, IStabilityPool {
* - Increases deposit, and takes new snapshots of accumulators P and S
* - Sends depositor's accumulated ETH gains to depositor
*/
function provideToSP(uint256 _amount) external override {
function provideToSP(uint256 _amount, bool _doClaim) external override {
_requireNonZeroAmount(_amount);

activePool.mintAggInterest();

uint256 initialDeposit = deposits[msg.sender].initialValue;

uint256 depositorETHGain = getDepositorETHGain(msg.sender);
uint256 currentETHGain = getDepositorETHGain(msg.sender);
uint256 compoundedBoldDeposit = getCompoundedBoldDeposit(msg.sender);
uint256 boldLoss = initialDeposit - compoundedBoldDeposit; // Needed only for event log

Expand All @@ -297,26 +298,25 @@ contract StabilityPool is LiquityBase, Ownable, CheckContract, IStabilityPool {
_updateDepositAndSnapshots(msg.sender, newDeposit);
emit UserDepositChanged(msg.sender, newDeposit);

emit ETHGainWithdrawn(msg.sender, depositorETHGain, boldLoss); // Bold Loss required for event log

_sendETHGainToDepositor(depositorETHGain);
_stashOrSendETHGains(msg.sender, currentETHGain, boldLoss, _doClaim);
assert(getDepositorETHGain(msg.sender) == 0);
}

/* withdrawFromSP():
* - Calculates depositor's ETH gain
* - Calculates the compounded deposit
* - Sends the requested BOLD withdrawal to depositor
* - Sends the requested BOLD withdrawal to depositor
* - (If _amount > userDeposit, the user withdraws all of their compounded deposit)
* - Decreases deposit by withdrawn amount and takes new snapshots of accumulators P and S
*/
function withdrawFromSP(uint256 _amount) external override {
function withdrawFromSP(uint256 _amount, bool _doClaim) external override {
// TODO: if (_amount !=0) {_requireNoUnderCollateralizedTroves();}
uint256 initialDeposit = deposits[msg.sender].initialValue;
_requireUserHasDeposit(initialDeposit);

activePool.mintAggInterest();

uint256 depositorETHGain = getDepositorETHGain(msg.sender);
uint256 currentETHGain = getDepositorETHGain(msg.sender);

uint256 compoundedBoldDeposit = getCompoundedBoldDeposit(msg.sender);
uint256 BoldtoWithdraw = LiquityMath._min(_amount, compoundedBoldDeposit);
Expand All @@ -329,9 +329,57 @@ contract StabilityPool is LiquityBase, Ownable, CheckContract, IStabilityPool {
_updateDepositAndSnapshots(msg.sender, newDeposit);
emit UserDepositChanged(msg.sender, newDeposit);

emit ETHGainWithdrawn(msg.sender, depositorETHGain, boldLoss); // Bold Loss required for event log
_stashOrSendETHGains(msg.sender, currentETHGain, boldLoss, _doClaim);
assert(getDepositorETHGain(msg.sender) == 0);
}

function _stashOrSendETHGains(address _depositor, uint256 _currentETHGain, uint256 _boldLoss, bool _doClaim) internal {
if (_doClaim) {
// Get the total gain (stashed + current), zero the stashed balance, send total gain to depositor
uint ETHToSend = _getTotalETHGainAndZeroStash(_depositor, _currentETHGain);

emit ETHGainWithdrawn(msg.sender, ETHToSend, _boldLoss); // Bold Loss required for event log
_sendETHGainToDepositor(ETHToSend);

} else {
// Just stash the current gain
stashedETH[_depositor] += _currentETHGain;
}
}

function _getTotalETHGainAndZeroStash(address _depositor, uint256 _currentETHGain) internal returns (uint256) {
uint256 stashedETHGain = stashedETH[_depositor];
uint256 totalETHGain = stashedETHGain + _currentETHGain;

// TODO: Gas - saves gas when stashedETHGain == 0?
if (stashedETHGain > 0) {stashedETH[_depositor] = 0;}

return totalETHGain;
}

// TODO: Make this also claim BOlD gains when they are implemented
function claimAllETHGains() external {
// We don't require they have a deposit: they may have stashed gains and no deposit
uint256 initialDeposit = deposits[msg.sender].initialValue;
uint256 boldLoss;
uint256 currentETHGain;

activePool.mintAggInterest();

// If they have a deposit, update it and update its snapshots
if (initialDeposit > 0) {
currentETHGain = getDepositorETHGain(msg.sender); // Only active deposits can have a current ETH gain

uint256 compoundedBoldDeposit = getCompoundedBoldDeposit(msg.sender);
boldLoss = initialDeposit - compoundedBoldDeposit; // Needed only for event log

_updateDepositAndSnapshots(msg.sender, compoundedBoldDeposit);
}

uint256 ETHToSend = _getTotalETHGainAndZeroStash(msg.sender, currentETHGain);

_sendETHGainToDepositor(depositorETHGain);
_sendETHGainToDepositor(ETHToSend);
assert(getDepositorETHGain(msg.sender) == 0);
}

// --- Liquidation functions ---
Expand Down Expand Up @@ -364,8 +412,8 @@ contract StabilityPool is LiquityBase, Ownable, CheckContract, IStabilityPool {
* Compute the Bold and ETH rewards. Uses a "feedback" error correction, to keep
* the cumulative error in the P and S state variables low:
*
* 1) Form numerators which compensate for the floor division errors that occurred the last time this
* function was called.
* 1) Form numerators which compensate for the floor division errors that occurred the last time this
* function was called.
* 2) Calculate "per-unit-staked" ratios.
* 3) Multiply each ratio back by its denominator, to reveal the current floor division error.
* 4) Store these errors for use in the next correction when this function is called.
Expand Down
27 changes: 23 additions & 4 deletions contracts/src/test/TestContracts/BaseTest.sol
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Expand Up @@ -160,18 +160,37 @@ contract BaseTest is Test {
assertEq(recoveryMode, _enabled);
}

function makeSPDeposit(address _account, uint256 _amount) public {
function makeSPDepositAndClaim(address _account, uint256 _amount) public {
vm.startPrank(_account);
stabilityPool.provideToSP(_amount);
stabilityPool.provideToSP(_amount, true);
vm.stopPrank();
}

function makeSPWithdrawal(address _account, uint256 _amount) public {
function makeSPDepositNoClaim(address _account, uint256 _amount) public {
vm.startPrank(_account);
stabilityPool.withdrawFromSP(_amount);
stabilityPool.provideToSP(_amount, false);
vm.stopPrank();
}

function makeSPWithdrawalAndClaim(address _account, uint256 _amount) public {
vm.startPrank(_account);
stabilityPool.withdrawFromSP(_amount, true);
vm.stopPrank();
}

function makeSPWithdrawalNoClaim(address _account, uint256 _amount) public {
vm.startPrank(_account);
stabilityPool.withdrawFromSP(_amount, false);
vm.stopPrank();
}

function claimAllETHGains(address _account) public {
vm.startPrank(_account);
stabilityPool.claimAllETHGains();
vm.stopPrank();
}


function closeTrove(address _account, uint256 _troveId) public {
vm.startPrank(_account);
borrowerOperations.closeTrove(_troveId);
Expand Down
39 changes: 28 additions & 11 deletions contracts/src/test/TestContracts/DevTestSetup.sol
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Expand Up @@ -91,8 +91,8 @@ contract DevTestSetup is BaseTest {
uint256 CTroveId = openTroveNoHints100pct(C, 5 ether, troveDebtRequest_C, interestRate);

// A and B deposit to SP
makeSPDeposit(A, troveDebtRequest_A);
makeSPDeposit(B, troveDebtRequest_B);
makeSPDepositAndClaim(A, troveDebtRequest_A);
makeSPDepositAndClaim(B, troveDebtRequest_B);

// Price drops, C becomes liquidateable
price = 1025e18;
Expand All @@ -117,27 +117,44 @@ contract DevTestSetup is BaseTest {
uint256 troveDebtRequest_D = 2250e18;
uint256 interestRate = 5e16; // 5%

TroveIDs memory troveIDs;

uint256 price = 2000e18;
priceFeed.setPrice(price);

uint256 ATroveId = openTroveNoHints100pct(A, 5 ether, troveDebtRequest_A, interestRate);
uint256 BTroveId = openTroveNoHints100pct(B, 5 ether, troveDebtRequest_B, interestRate);
uint256 CTroveId = openTroveNoHints100pct(C, 25e17, troveDebtRequest_C, interestRate);
uint256 DTroveId = openTroveNoHints100pct(D, 25e17, troveDebtRequest_D, interestRate);
troveIDs.A = openTroveNoHints100pct(A, 5 ether, troveDebtRequest_A, interestRate);
troveIDs.B = openTroveNoHints100pct(B, 5 ether, troveDebtRequest_B, interestRate);
troveIDs.C = openTroveNoHints100pct(C, 25e17, troveDebtRequest_C, interestRate);
troveIDs.D = openTroveNoHints100pct(D, 25e17, troveDebtRequest_D, interestRate);

// A and B deposit to SP
makeSPDeposit(A, troveDebtRequest_A);
makeSPDeposit(B, troveDebtRequest_B);
makeSPDepositAndClaim(A, troveDebtRequest_A);
makeSPDepositAndClaim(B, troveDebtRequest_B);

// Price drops, C and D become liquidateable
price = 1050e18;
priceFeed.setPrice(price);

assertFalse(troveManager.checkRecoveryMode(price));
assertLt(troveManager.getCurrentICR(CTroveId, price), troveManager.MCR());
assertLt(troveManager.getCurrentICR(DTroveId, price), troveManager.MCR());
assertLt(troveManager.getCurrentICR(troveIDs.C, price), troveManager.MCR());
assertLt(troveManager.getCurrentICR(troveIDs.D, price), troveManager.MCR());

return (ATroveId, BTroveId, CTroveId, DTroveId);
return (troveIDs.A, troveIDs.B, troveIDs.C, troveIDs.D);
}

function _setupForSPDepositAdjustments() internal returns (TroveIDs memory) {
TroveIDs memory troveIDs;
(troveIDs.A, troveIDs.B, troveIDs.C, troveIDs.D) = _setupForBatchLiquidateTrovesPureOffset();

// A liquidates C
liquidate(A, troveIDs.C);

// D sends BOLD to A and B so they have some to use in tests
transferBold(D, A, boldToken.balanceOf(D) / 2);
transferBold(D, B, boldToken.balanceOf(D));

assertEq(troveManager.getTroveStatus(troveIDs.C), 3); // Status 3 - closed by liquidation
return troveIDs;
}

function _setupForBatchLiquidateTrovesPureRedist() internal returns (uint256, uint256, uint256, uint256) {
Expand Down
8 changes: 4 additions & 4 deletions contracts/src/test/basicOps.t.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -140,13 +140,13 @@ contract BasicOps is DevTestSetup {
borrowerOperations.openTrove(A, 0, 2e18, 2000e18, 0, 0, 0);

// A makes an SP deposit
stabilityPool.provideToSP(100e18);
makeSPDepositAndClaim(A, 100e18);

// time passes
vm.warp(block.timestamp + 7 days);

// A tops up their SP deposit
stabilityPool.provideToSP(100e18);
makeSPDepositAndClaim(A, 100e18);

// Check A's balance decreased and SP deposit increased
assertEq(boldToken.balanceOf(A), 1800e18);
Expand All @@ -159,7 +159,7 @@ contract BasicOps is DevTestSetup {
borrowerOperations.openTrove(A, 0, 2e18, 2000e18, 0, 0, 0);

// A makes an SP deposit
stabilityPool.provideToSP(100e18);
makeSPDepositAndClaim(A, 100e18);

// time passes
vm.warp(block.timestamp + 7 days);
Expand All @@ -169,7 +169,7 @@ contract BasicOps is DevTestSetup {
assertEq(stabilityPool.getCompoundedBoldDeposit(A), 100e18);

// A withdraws their full SP deposit
stabilityPool.withdrawFromSP(100e18);
makeSPWithdrawalAndClaim(A, 100e18);

// Check A's balance increased and SP deposit decreased to 0
assertEq(boldToken.balanceOf(A), 2000e18);
Expand Down
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