Add oracle logic fallback price tests

liquity · Sep 6, 2024 · bbf0e6f · bbf0e6f
1 parent 55ccbff
commit bbf0e6f
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Showing 5 changed files with 307 additions and 62 deletions.
diff --git a/contracts/src/Interfaces/IMainnetPriceFeed.sol b/contracts/src/Interfaces/IMainnetPriceFeed.sol
@@ -3,7 +3,13 @@ import "../Interfaces/IPriceFeed.sol";
 import "../Dependencies/AggregatorV3Interface.sol";
 
 pragma solidity ^0.8.0;
-
 interface IMainnetPriceFeed is IPriceFeed {
+     enum PriceSource {
+          primary,
+          ETHUSDxCanonical,
+          lastGoodPrice
+     }
+
      function ethUsdOracle() external view returns (AggregatorV3Interface, uint256, uint8);
+     function priceSource() external view returns (PriceSource);
 }
diff --git a/contracts/src/PriceFeeds/CompositePriceFeed.sol b/contracts/src/PriceFeeds/CompositePriceFeed.sol
@@ -26,16 +26,20 @@ contract CompositePriceFeed is MainnetPriceFeedBase {
         rateProviderAddress = _rateProviderAddress;
     }
 
+    // Returns:
+    // - The price, using the current price calculation
+    // - A bool that is true if a) the system was not shut down prior to this call and b) an oracle failed during this call.
     function fetchPrice() public returns (uint256, bool) {
         // If branch is live and the primary oracle setup has been working, try to use it 
         if (priceSource == PriceSource.primary) {return _fetchPrice();}
 
         // If branch is already shut down and using ETH-USD * canonical_rate, try to use that
         if (priceSource == PriceSource.ETHUSDxCanonical) {
                 (uint256 ethUsdPrice, bool ethUsdOracleDown) = _getOracleAnswer(ethUsdOracle);
-                //... but if the ETH-USD oracle *also* fails here, use the lastGoodPrice
+                //... but if the ETH-USD oracle *also* fails here, switch to using the lastGoodPrice
                 if(ethUsdOracleDown) {
                     // No need to shut down, since branch already is shut down
+                    priceSource = PriceSource.lastGoodPrice;
                     return (lastGoodPrice, false);
                 } else {
                     return (_fetchPriceETHUSDxCanonical(ethUsdPrice), false);

diff --git a/contracts/src/PriceFeeds/MainnetPriceFeedBase.sol b/contracts/src/PriceFeeds/MainnetPriceFeedBase.sol
@@ -12,12 +12,6 @@ import "../BorrowerOperations.sol";
 abstract contract MainnetPriceFeedBase is IMainnetPriceFeed, Ownable {
     // Dummy flag raised when the collateral branch gets shut down.
     // Should be removed after actual shutdown logic is implemented.
-
-    enum PriceSource {
-        primary,
-        ETHUSDxCanonical,
-        lastGoodPrice
-    }
 
     PriceSource public priceSource;
 

diff --git a/contracts/src/PriceFeeds/RETHPriceFeed.sol b/contracts/src/PriceFeeds/RETHPriceFeed.sol
@@ -39,7 +39,7 @@ contract RETHPriceFeed is CompositePriceFeed, IRETHPriceFeed {
         (uint256 rEthEthPrice, bool rEthEthOracleDown) = _getOracleAnswer(rEthEthOracle);
 
         // If the ETH-USD feed is down, shut down and switch to the last good price seen by the system
-        // since we always need the
+        // since we need the ETH-USD price for both calcs: 1) ETH-USD x RETH-ETH, and 2) ETH-USD x canonical
         if (ethUsdOracleDown) {return (_shutDownAndSwitchToLastGoodPrice(address(ethUsdOracle.aggregator)), true);}
         // If the ETH-USD feed is live but the RETH-ETH oracle is down, shutdown and substitute RETH-ETH with the canonical rate
         if (rEthEthOracleDown) {return (_shutDownAndSwitchToETHUSDxCanonical(address(rEthEthOracle.aggregator), ethUsdPrice), true);}