Patch for real -> virtual -> real unit conversion. (#100)

Patch for real -> virtual -> real unit conversion.

Author: bweick

contracts/protocol/SetToken.sol

@@ -554,14 +554,20 @@ contract SetToken is ERC20 {
     }
 
     /**
-     * Takes a real unit and divides by the position multiplier to return the virtual unit
+     * Takes a real unit and divides by the position multiplier to return the virtual unit. Negative units will
+     * be rounded away from 0 so no need to check that unit will be rounded down to 0 in conversion.
      */
     function _convertRealToVirtualUnit(int256 _realUnit) internal view returns(int256) {
         int256 virtualUnit = _realUnit.conservativePreciseDiv(positionMultiplier);
 
-        // These checks ensure that the virtual unit does not return a result that has rounded down to 0
+        // This check ensures that the virtual unit does not return a result that has rounded down to 0
         if (_realUnit > 0 && virtualUnit == 0) {
-            revert("Virtual unit conversion invalid");
+            revert("Real to Virtual unit conversion invalid");
+        }
+
+        // This check ensures that when converting back to realUnits the unit won't be rounded down to 0
+        if (_realUnit > 0 && _convertVirtualToRealUnit(virtualUnit) == 0) {
+            revert("Virtual to Real unit conversion invalid");
         }
 
         return virtualUnit;

hardhat.config.ts

@@ -41,8 +41,8 @@ const config: HardhatUserConfig = {
     localhost: {
       url: "http://127.0.0.1:8545",
       timeout: 100000,
-      gas: 9500000,
-      blockGasLimit: 9500000,
+      gas: 12000000,
+      blockGasLimit: 12000000,
     },
     kovan: {
       url: "https://kovan.infura.io/v3/" + process.env.INFURA_TOKEN,

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@setprotocol/set-protocol-v2",
-  "version": "0.0.43",
+  "version": "0.0.44",
   "description": "",
   "main": "dist",
   "types": "dist/types",

test/protocol/setToken.spec.ts

@@ -463,7 +463,19 @@ describe("SetToken", () => {
         });
 
         it("should revert", async () => {
-          await expect(subject()).to.be.revertedWith("Virtual unit conversion invalid");
+          await expect(subject()).to.be.revertedWith("Real to Virtual unit conversion invalid");
+        });
+      });
+
+      describe("when the conversion back to real units would round down to 0", async () => {
+        beforeEach(async () => {
+          subjectNewUnit = BigNumber.from(1);
+          const hugePositionMultiplier = ether(.99);
+          await setToken.connect(subjectCaller.wallet).editPositionMultiplier(hugePositionMultiplier);
+        });
+
+        it("should revert", async () => {
+          await expect(subject()).to.be.revertedWith("Virtual to Real unit conversion invalid");
         });
       });