added dr eq range back

Author: aalavandhan

spot-vaults/contracts/DRBalancerVault.sol

@@ -13,7 +13,8 @@ import { IERC20MetadataUpgradeable } from "@openzeppelin/contracts-upgradeable/t
 import { IPerpetualTranche } from "@ampleforthorg/spot-contracts/contracts/_interfaces/IPerpetualTranche.sol";
 import { IRolloverVault } from "@ampleforthorg/spot-contracts/contracts/_interfaces/IRolloverVault.sol";
 import { ERC20Helpers } from "@ampleforthorg/spot-contracts/contracts/_utils/ERC20Helpers.sol";
-import { UnauthorizedCall, InvalidPerc } from "./_interfaces/errors/CommonErrors.sol";
+import { UnauthorizedCall, InvalidPerc, InvalidRange } from "./_interfaces/errors/CommonErrors.sol";
+import { Range } from "@ampleforthorg/spot-contracts/contracts/_interfaces/CommonTypes.sol";
 import { LastRebalanceTooRecent, SlippageTooHigh, InvalidLagFactor } from "./_interfaces/errors/DRBalancerErrors.sol";
 
 /**
@@ -99,6 +100,10 @@ contract DRBalancerVault is
     /// @notice The target system deviation ratio (typically 1.0 = DR_ONE, using 8 decimals).
     uint256 public targetDR;
 
+    /// @notice The range of deviation ratios which define the equilibrium zone.
+    /// @dev When the system's dr is within the equilibrium zone, no value is transferred during rebalance.
+    Range public equilibriumDR;
+
     /// @notice The lag factor for underlying->perp swaps (when DR is high).
     uint256 public lagFactorUnderlyingToPerp;
 
@@ -198,6 +203,11 @@ contract DRBalancerVault is
         // Default configuration
         // Target DR is 1.0 (system in balance) with 8 decimals
         targetDR = DR_ONE;
+        // Equilibrium DR range (skip rebalances when DR is within this window)
+        equilibriumDR = Range({
+            lower: (DR_ONE * 95) / 100,
+            upper: (DR_ONE * 105) / 100
+        });
         // Default lag factors
         lagFactorUnderlyingToPerp = 3;
         lagFactorPerpToUnderlying = 3;
@@ -216,10 +226,22 @@ contract DRBalancerVault is
         keeper = keeper_;
     }
 
-    /// @notice Updates the target system deviation ratio.
+    /// @notice Updates the target system deviation ratio and equilibrium DR range together.
     /// @param targetDR_ The new target DR as a fixed point number with 8 decimals.
-    function updateTargetDR(uint256 targetDR_) external onlyOwner {
+    /// @param equilibriumDR_ The new equilibrium DR range as tuple of fixed-point numbers with {DR_DECIMALS} places.
+    function updateTargetAndEquilibriumDR(
+        uint256 targetDR_,
+        Range memory equilibriumDR_
+    ) external onlyOwner {
+        if (
+            equilibriumDR_.lower >= equilibriumDR_.upper ||
+            targetDR_ <= equilibriumDR_.lower ||
+            targetDR_ >= equilibriumDR_.upper
+        ) {
+            revert InvalidRange();
+        }
         targetDR = targetDR_;
+        equilibriumDR = equilibriumDR_;
     }
 
     /// @notice Updates the lag factors for rebalancing.
@@ -528,6 +550,11 @@ contract DRBalancerVault is
             return (0, false);
         }
 
+        // Skip rebalancing if DR is within the equilibrium range.
+        if (dr >= equilibriumDR.lower && dr <= equilibriumDR.upper) {
+            return (0, false);
+        }
+
         // Determine direction, magnitude, and available liquidity for the swap
         // If DR < target: perpTVL is too high, redeem perps to decrease it
         // If DR > target: perpTVL is too low, mint perps to increase it

spot-vaults/test/DRBalancerVault.ts

@@ -76,6 +76,9 @@ describe("DRBalancerVault", function () {
 
       // Target DR is 1.0 (system in balance) with 8 decimals
       expect(await vault.targetDR()).to.eq(DR_ONE);
+      const eqRange = await vault.equilibriumDR();
+      expect(eqRange[0]).to.eq(drFP("0.95"));
+      expect(eqRange[1]).to.eq(drFP("1.05"));
 
       expect(await vault.lagFactorUnderlyingToPerp()).to.eq(3);
       expect(await vault.lagFactorPerpToUnderlying()).to.eq(3);
@@ -106,22 +109,44 @@ describe("DRBalancerVault", function () {
     });
   });
 
-  describe("#updateTargetDR", function () {
+  describe("#updateTargetAndEquilibriumDR", function () {
     describe("when triggered by non-owner", function () {
       it("should revert", async function () {
         const { vault } = await loadFixture(setupContracts);
         await vault.renounceOwnership();
-        await expect(vault.updateTargetDR(DR_ONE)).to.be.revertedWith(
-          "Ownable: caller is not the owner",
-        );
+        await expect(
+          vault.updateTargetAndEquilibriumDR(DR_ONE, [drFP("0.9"), drFP("1.1")]),
+        ).to.be.revertedWith("Ownable: caller is not the owner");
+      });
+    });
+
+    describe("when target is outside range", function () {
+      it("should revert", async function () {
+        const { vault } = await loadFixture(setupContracts);
+        await expect(
+          vault.updateTargetAndEquilibriumDR(DR_ONE, [drFP("1.01"), drFP("1.1")]),
+        ).to.be.revertedWithCustomError(vault, "InvalidRange");
+      });
+    });
+
+    describe("when target equals a boundary", function () {
+      it("should revert", async function () {
+        const { vault } = await loadFixture(setupContracts);
+        await expect(
+          vault.updateTargetAndEquilibriumDR(DR_ONE, [DR_ONE, drFP("1.1")]),
+        ).to.be.revertedWithCustomError(vault, "InvalidRange");
       });
     });
 
     describe("when valid", function () {
-      it("should update target DR", async function () {
+      it("should update target DR and equilibrium range", async function () {
         const { vault } = await loadFixture(setupContracts);
-        await vault.updateTargetDR((DR_ONE * 110n) / 100n);
-        expect(await vault.targetDR()).to.eq((DR_ONE * 110n) / 100n);
+        const newTarget = drFP("1.02");
+        await vault.updateTargetAndEquilibriumDR(newTarget, [drFP("0.98"), drFP("1.1")]);
+        expect(await vault.targetDR()).to.eq(newTarget);
+        const r = await vault.equilibriumDR();
+        expect(r[0]).to.eq(drFP("0.98"));
+        expect(r[1]).to.eq(drFP("1.1"));
       });
     });
   });

spot-vaults/test/DRBalancerVault_rebalance.ts

@@ -89,6 +89,7 @@ describe("DRBalancerVault", function () {
   describe("#computeRebalanceAmount", function () {
     // Test Matrix:
     // - DR at target: returns 0
+    // - DR within equilibrium range: returns 0
     // - DR below target: perp -> underlying swap (isUnderlyingIntoPerp = false)
     // - DR above target: underlying -> perp swap (isUnderlyingIntoPerp = true)
     // - Caps: minRebalanceVal threshold, availableLiquidity cap, requiredChange cap
@@ -101,8 +102,8 @@ describe("DRBalancerVault", function () {
         const [amt, isUnderlyingIntoPerp] =
           await vault.computeRebalanceAmount.staticCall();
         expect(amt).to.eq(0n);
-        // When DR = targetDR, goes to else branch (dr >= targetDR), so isUnderlyingIntoPerp = true
-        expect(isUnderlyingIntoPerp).to.eq(true);
+        // When DR is within equilibrium range, no swap occurs and direction is false
+        expect(isUnderlyingIntoPerp).to.eq(false);
       });
     });
 
@@ -345,7 +346,7 @@ describe("DRBalancerVault", function () {
         await time.increase(DAY + 1);
         await expect(vault.rebalance())
           .to.emit(vault, "Rebalance")
-          .withArgs(drFP("1"), drFP("1"), 0n, true);
+          .withArgs(drFP("1"), drFP("1"), 0n, false);
       });
     });
 
@@ -354,10 +355,10 @@ describe("DRBalancerVault", function () {
         const { vault, rolloverVault } = await loadFixture(setupWithBalancedLiquidity);
         await rolloverVault.mockMethod("deviationRatio()", [drFP("1")]);
 
-        // When DR = targetDR, isUnderlyingIntoPerp = true (dr >= targetDR branch)
+        // When DR is within equilibrium range, no swap occurs and direction is false
         await expect(vault.rebalance())
           .to.emit(vault, "Rebalance")
-          .withArgs(drFP("1"), drFP("1"), 0n, true);
+          .withArgs(drFP("1"), drFP("1"), 0n, false);
       });
 
       it("should update lastRebalanceTimestampSec", async function () {