Merge pull request #770 from reserve-protocol/polish-backing-overview

FacadeRead.backingOverview nits

Author: tbrent

contracts/facade/FacadeRead.sol

@@ -253,14 +253,35 @@ contract FacadeRead is IFacadeRead {
         uint256 supply = rToken.totalSupply();
         if (supply == 0) return (0, 0);
 
-        // {BU}
-        uint192 basketsNeeded = rToken.basketsNeeded();
-
-        // {BU}
-        BasketRange memory buRange = basketRange(rToken, basketsNeeded);
+        uint192 basketsNeeded = rToken.basketsNeeded(); // {BU}
+        uint192 uoaNeeded; // {UoA}
+        uint192 uoaHeldInBaskets; // {UoA}
+        {
+            (address[] memory basketERC20s, uint256[] memory quantities) = rToken
+                .main()
+                .basketHandler()
+                .quote(basketsNeeded, FLOOR);
+
+            IAssetRegistry reg = rToken.main().assetRegistry();
+            IBackingManager bm = rToken.main().backingManager();
+            for (uint256 i = 0; i < basketERC20s.length; i++) {
+                IAsset asset = reg.toAsset(IERC20(basketERC20s[i]));
+
+                // {UoA/tok}
+                (uint192 low, ) = asset.price();
+
+                // {tok}
+                uint192 needed = shiftl_toFix(quantities[i], -int8(asset.erc20Decimals()));
+
+                // {UoA} = {UoA} + {tok}
+                uoaNeeded += needed.mul(low);
+
+                // {UoA} = {UoA} + {tok} * {UoA/tok}
+                uoaHeldInBaskets += fixMin(needed, asset.bal(address(bm))).mul(low);
+            }
 
-        // {1} = {UoA} / {UoA}
-        backing = buRange.bottom.div(basketsNeeded);
+            backing = uoaHeldInBaskets.div(uoaNeeded);
+        }
 
         // Compute overCollateralization
         IAsset rsrAsset = rToken.main().assetRegistry().toAsset(rToken.main().rsr());
@@ -275,12 +296,6 @@ contract FacadeRead is IFacadeRead {
         // {UoA} = {tok} * {UoA/tok}
         uint192 rsrUoA = rsrBal.mul(lowPrice);
 
-        // {UoA/BU}
-        (uint192 buPriceLow, ) = rToken.main().basketHandler().price();
-
-        // {UoA} = {BU} * {UoA/BU}
-        uint192 uoaNeeded = basketsNeeded.mul(buPriceLow);
-
         // {1} = {UoA} / {UoA}
         overCollateralization = rsrUoA.div(uoaNeeded);
     }

scripts/addresses/mainnet-2.1.0/1-tmp-deployments.json

@@ -26,7 +26,7 @@
   "facadeMonitor": "0xF3458200eDe2C5A592757dc0BA9A915e9CCA77C6",
   "cvxMiningLib": "0xA6B8934a82874788043A75d50ca74a18732DC660",
   "rsrAsset": "0x9cd0F8387672fEaaf7C269b62c34C53590d7e948",
-  "facadeRead": "0x15f06B2907594905D820a4AB3631f4b097a0bE07",
+  "facadeRead": "0xf535Cab96457558eE3eeAF1402fCA6441E832f08",
   "facadeWrite": "0x1656D8aAd7Ee892582B9D5c2E9992d9f94ff3629",
   "facadeAct": "0x933c5DBdA80f03C102C560e9ed0c29812998fA78"
 }

test/FacadeRead.test.ts

@@ -211,7 +211,7 @@ describe('FacadeRead contract', () => {
       let [backing, overCollateralization] = await facade.callStatic.backingOverview(rToken.address)
 
       // Check values - Fully collateralized and no over-collateralization
-      expect(backing).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
       expect(overCollateralization).to.equal(0)
 
       // Mint some RSR
@@ -224,16 +224,16 @@ describe('FacadeRead contract', () => {
       ;[backing, overCollateralization] = await facade.callStatic.backingOverview(rToken.address)
 
       // Check values - Fully collateralized and fully over-collateralized
-      expect(backing).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
       expect(overCollateralization).to.be.closeTo(fp('0.5'), 10)
 
       // Stake more RSR
       await rsr.connect(addr1).approve(stRSR.address, stakeAmount)
       await stRSR.connect(addr1).stake(stakeAmount)
       ;[backing, overCollateralization] = await facade.callStatic.backingOverview(rToken.address)
 
-      expect(backing).to.be.closeTo(fp('1'), 10)
-      expect(overCollateralization).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
+      expect(overCollateralization).to.equal(fp('1'))
 
       // Redeem all RTokens
       await rToken.connect(addr1).redeem(issueAmount, await basketHandler.nonce())
@@ -246,14 +246,39 @@ describe('FacadeRead contract', () => {
       expect(overCollateralization).to.equal(0)
     })
 
+    it('Should return backingOverview backing correctly when undercollateralized', async () => {
+      const backingManager = await main.backingManager()
+      await usdc.burn(backingManager, (await usdc.balanceOf(backingManager)).div(2))
+      await basketHandler.refreshBasket()
+      const [backing, overCollateralization] = await facade.callStatic.backingOverview(
+        rToken.address
+      )
+
+      // Check values - Fully collateralized and no over-collateralization
+      expect(backing).to.equal(fp('0.875'))
+      expect(overCollateralization).to.equal(0)
+    })
+
     it('Should return backingOverview backing correctly when an asset price is 0', async () => {
       await setOraclePrice(tokenAsset.address, bn(0))
       const [backing, overCollateralization] = await facade.callStatic.backingOverview(
         rToken.address
       )
 
       // Check values - Fully collateralized and no over-collateralization
-      expect(backing).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
+      expect(overCollateralization).to.equal(0)
+    })
+
+    it('Should return backingOverview backing correctly when basket collateral is UNPRICED', async () => {
+      await setOraclePrice(tokenAsset.address, MAX_UINT256.div(2).sub(1))
+      await basketHandler.refreshBasket()
+      const [backing, overCollateralization] = await facade.callStatic.backingOverview(
+        rToken.address
+      )
+
+      // Check values - Fully collateralized and no over-collateralization
+      expect(backing).to.equal(fp('1')) // since price is unknown for uoaHeldInBaskets
       expect(overCollateralization).to.equal(0)
     })
 
@@ -265,7 +290,7 @@ describe('FacadeRead contract', () => {
       )
 
       // Check values - Fully collateralized and no over-collateralization
-      expect(backing).to.be.closeTo(fp('0'), 10)
+      expect(backing).to.equal(fp('1'))
       expect(overCollateralization).to.equal(0)
     })
 
@@ -283,7 +308,7 @@ describe('FacadeRead contract', () => {
       )
 
       // Check values - Fully collateralized and no over-collateralization
-      expect(backing).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
       expect(overCollateralization).to.equal(fp('0.5'))
 
       // Set price to 0
@@ -294,7 +319,7 @@ describe('FacadeRead contract', () => {
       )
 
       // Check values - Fully collateralized and no over-collateralization
-      expect(backing2).to.be.closeTo(fp('1'), 10)
+      expect(backing2).to.equal(fp('1'))
       expect(overCollateralization2).to.equal(0)
     })
 
@@ -309,14 +334,14 @@ describe('FacadeRead contract', () => {
 
       // Check values - Fully collateralized and with 50%-collateralization
       let [backing, overCollateralization] = await facade.callStatic.backingOverview(rToken.address)
-      expect(backing).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
       expect(overCollateralization).to.equal(fp('0.5'))
 
       await setOraclePrice(rsrAsset.address, MAX_UINT256.div(2).sub(1))
       ;[backing, overCollateralization] = await facade.callStatic.backingOverview(rToken.address)
 
       // Check values - Fully collateralized and no over-collateralization
-      expect(backing).to.be.closeTo(fp('1'), 10)
+      expect(backing).to.equal(fp('1'))
       expect(overCollateralization).to.equal(0)
     })