chore: simplify SKy transfer

makerdao · Jan 9, 2025 · 8e83f5e · 8e83f5e
1 parent 1f64a16
commit 8e83f5e
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Showing 2 changed files with 10 additions and 41 deletions.
diff --git a/src/DssSpell.sol b/src/DssSpell.sol
@@ -236,24 +236,16 @@ contract DssSpellAction is DssAction {
     /// @param usr The SKY receiver.
     /// @param wad The SKY amount in wad precision (10 ** 18).
     function _transferSky(address usr, uint256 wad) internal {
-        // Note: Calculate the remainder
-        uint256 wadRem = wad % MKR_SKY_RATE;
-        // Note: The remainder has to be strictly less than the rate (24_000)
-        require(wadRem < MKR_SKY_RATE, "transferUsds/wrong-remainder");
-        // Note: this extra amount is used for enforce exact conversion and avoiding rounding errors
-        uint256 extraWad;
-        if (wadRem != 0) {
-            extraWad = MKR_SKY_RATE - wadRem;
-        }
-        // Note: Calculate the amount of MKR required
-        require((wad + extraWad) % MKR_SKY_RATE == 0, "transferSky/non-exact-conversion");
-        uint256 mkrWad = (wad + extraWad) / MKR_SKY_RATE;
+        // Note: Calculate the equivalent amount of MKR required
+        uint256 mkrWad = wad / MKR_SKY_RATE;
+        // Note: if rounding error is expected, add an extra wei of MKR
+        if (wad % MKR_SKY_RATE != 0) { mkrWad++; }
         // Note: Approve MKR_SKY for the amount sent to be able to convert it
         MKR.approve(MKR_SKY, mkrWad);
-        // Note: Convert the calculated amount to SKY
+        // Note: Convert the calculated amount to SKY for `PAUSE_PROXY`
         MkrSkyLike(MKR_SKY).mkrToSky(address(this), mkrWad);
-        // Note: Transer the required SKY to 'usr'
-        SkyLike(SKY).transfer(usr, wad);
+        // Note: Transfer originally requested amount, leaving extra on the `PAUSE_PROXY`
+        GemAbstract(SKY).transfer(usr, wad);
     }
 }
 

diff --git a/src/DssSpell.t.sol b/src/DssSpell.t.sol
@@ -674,11 +674,6 @@ contract DssSpellTest is DssSpellTestBase {
         int256 sky;
     }
 
-    struct RoundingErrorHandling {
-        int256 mkrSkyRate;
-        int256 extraSky;
-    }
-
     function testPayments() public { // add the `skipped` modifier to skip
         bool ignoreTotalSupplyDaiUsds = true; // Set to false unless there is SubDAO spell interference
 
@@ -706,14 +701,6 @@ contract DssSpellTest is DssSpellTestBase {
             Payee(address(sky),  wallets.addr("CLOAKY"),                                    438_000 ether)  // Note: ether is only a keyword helper
         ];
 
-        // Created a struct to avoid "Stack too deep" errors
-        RoundingErrorHandling memory roundingErrorHandling = RoundingErrorHandling({
-            mkrSkyRate: 24000,
-            // Set the variable with the amount of the  extra SKY that was sent to PAUSE_PROXY
-            // for each SKY payment do: extraSky += rate - (paymentAmount % rate)
-            extraSky: 24000 - 16000 // only one payment (BLUE - 550_000 SKY) is not divisible by rate
-        });
-
         // Fill the total values from exec sheet
         PaymentAmounts memory expectedTotalPayments = PaymentAmounts({
             dai:          0 ether, // Note: ether is only a keyword helper
@@ -724,8 +711,8 @@ contract DssSpellTest is DssSpellTestBase {
 
         // Fill the total values based on the source for the transfers above
         TreasuryAmounts memory expectedTreasuryBalancesDiff = TreasuryAmounts({
-            mkr: -int(988_000 ether + roundingErrorHandling.extraSky) / roundingErrorHandling.mkrSkyRate, // Note: ether is only a keyword helper
-            sky:            roundingErrorHandling.extraSky   // Note: ether is only a keyword helper
+            mkr: -(22916666666666666667 + 18250000000000000000), // Note: ether is only a keyword helper
+            sky: 8000
         });
 
         // Vote, schedule and warp, but not yet cast (to get correct surplus balance)
@@ -748,8 +735,7 @@ contract DssSpellTest is DssSpellTestBase {
         });
         PaymentAmounts memory calculatedTotalPayments;
         PaymentAmounts[] memory previousPayeeBalances = new PaymentAmounts[](payees.length);
-        // This is to account for the extra SKy we add for dealing with precision issues
-        int256 totalExtraSky;
+
         for (uint256 i = 0; i < payees.length; i++) {
             if (payees[i].token == address(dai)) {
                 calculatedTotalPayments.dai += payees[i].amount;
@@ -758,10 +744,6 @@ contract DssSpellTest is DssSpellTestBase {
             } else if (payees[i].token == address(usds)) {
                 calculatedTotalPayments.usds += payees[i].amount;
             } else if (payees[i].token == address(sky)) {
-                int256 rem = payees[i].amount % roundingErrorHandling.mkrSkyRate;
-                if (rem != 0) {
-                    totalExtraSky += roundingErrorHandling.mkrSkyRate - rem;
-                }
                 calculatedTotalPayments.sky += payees[i].amount;
             } else {
                 revert('TestPayments/unexpected-payee-token');
@@ -774,11 +756,6 @@ contract DssSpellTest is DssSpellTestBase {
             });
         }
 
-        // Check calculated vs expected totals
-        assertEq(roundingErrorHandling.extraSky,
-                 totalExtraSky,
-                "TestPayments/calculated-vs-expected-extra-sky-mismatch"
-        );
         assertEq(
             calculatedTotalPayments.dai,
             expectedTotalPayments.dai,