Merge pull request #35 from morpho-labs/fix/vault-conversion-zero

fix(oracle): require vault conversion not zero

Author: MerlinEgalite

src/ChainlinkOracle.sol

@@ -60,6 +60,8 @@ contract ChainlinkOracle is IOracle {
         require(
             address(vault) != address(0) || vaultConversionSample == 1, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE
         );
+        require(vaultConversionSample != 0, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_ZERO);
+
         VAULT = vault;
         VAULT_CONVERSION_SAMPLE = vaultConversionSample;
         BASE_FEED_1 = baseFeed1;
@@ -87,7 +89,7 @@ contract ChainlinkOracle is IOracle {
             ** (
                 36 + quoteTokenDecimals + quoteFeed1.getDecimals() + quoteFeed2.getDecimals() - baseTokenDecimals
                     - baseFeed1.getDecimals() - baseFeed2.getDecimals()
-            ) / VAULT_CONVERSION_SAMPLE;
+            ) / vaultConversionSample;
     }
 
     /* PRICE */

src/libraries/ErrorsLib.sol

@@ -9,6 +9,9 @@ library ErrorsLib {
     /// @notice Thrown when the answer returned by a Chainlink feed is negative.
     string constant NEGATIVE_ANSWER = "negative answer";
 
+    /// @notice Thrown when the vault conversion sample is 0.
+    string constant VAULT_CONVERSION_SAMPLE_IS_ZERO = "vault conversion sample is zero";
+
     /// @notice Thrown when the vault conversion sample is not 1 while vault = address(0).
     string constant VAULT_CONVERSION_SAMPLE_IS_NOT_ONE = "vault conversion sample is not one";
 }

test/ChainlinkOracleTest.sol

@@ -132,8 +132,14 @@ contract ChainlinkOracleTest is Test {
         assertApproxEqRel(oracle.price(), expectedPrice, deviation);
     }
 
+    function testConstructorZeroVaultConversionSample() public {
+        vm.expectRevert(bytes(ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_ZERO));
+        new ChainlinkOracle(sDaiVault, daiEthFeed, feedZero, usdcEthFeed, feedZero, 0, 18, 6);
+    }
+
     function testConstructorVaultZeroNonOneSample(uint256 vaultConversionSample) public {
-        vm.assume(vaultConversionSample != 1);
+        vaultConversionSample = bound(vaultConversionSample, 2, type(uint256).max);
+
         vm.expectRevert(bytes(ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE));
         new ChainlinkOracle(vaultZero, daiEthFeed, feedZero, usdcEthFeed, feedZero, vaultConversionSample, 18, 6);
     }