From 9c99de433e27f9d9464b1a873cc7bf8d9eefa7ea Mon Sep 17 00:00:00 2001
From: Jean-Grimal <jeanbgrimal@gmail.com>
Date: Mon, 8 Jan 2024 15:19:09 +0100
Subject: [PATCH] fix: handle idle markets APY

---
 src/blue/BlueSnippets.sol                        |  6 +++++-
 src/metamorpho/MetaMorphoSnippets.sol            |  5 ++++-
 test/forge/blue/TestBlueSnippets.sol             |  9 +++++++++
 test/forge/metamorpho/TestMetaMorphoSnippets.sol | 15 +++++++++++++++
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/blue/BlueSnippets.sol b/src/blue/BlueSnippets.sol
index 7ca68ae..114aa1d 100644
--- a/src/blue/BlueSnippets.sol
+++ b/src/blue/BlueSnippets.sol
@@ -80,7 +80,11 @@ contract BlueSnippets {
         view
         returns (uint256 borrowRate)
     {
-        borrowRate = IIrm(marketParams.irm).borrowRateView(marketParams, market).wTaylorCompounded(1);
+        if (marketParams.irm == address(0)) {
+            borrowRate = 0;
+        } else {
+            borrowRate = IIrm(marketParams.irm).borrowRateView(marketParams, market).wTaylorCompounded(1);
+        }
     }
 
     /**
diff --git a/src/metamorpho/MetaMorphoSnippets.sol b/src/metamorpho/MetaMorphoSnippets.sol
index 73fbd5a..b16d0e1 100644
--- a/src/metamorpho/MetaMorphoSnippets.sol
+++ b/src/metamorpho/MetaMorphoSnippets.sol
@@ -105,7 +105,10 @@ contract MetaMorphoSnippets {
         (uint256 totalSupplyAssets,, uint256 totalBorrowAssets,) = morpho.expectedMarketBalances(marketParams);
 
         // Get the borrow rate
-        uint256 borrowRate = IIrm(marketParams.irm).borrowRateView(marketParams, market);
+        uint256 borrowRate;
+        if (marketParams.irm != address(0)) {
+            borrowRate = IIrm(marketParams.irm).borrowRateView(marketParams, market).wTaylorCompounded(1);
+        }
 
         // Get the supply rate
         uint256 utilization = totalBorrowAssets == 0 ? 0 : totalBorrowAssets.wDivUp(totalSupplyAssets);
diff --git a/test/forge/blue/TestBlueSnippets.sol b/test/forge/blue/TestBlueSnippets.sol
index 20c3169..38818fb 100644
--- a/test/forge/blue/TestBlueSnippets.sol
+++ b/test/forge/blue/TestBlueSnippets.sol
@@ -107,6 +107,15 @@ contract TestIntegrationSnippets is BaseTest {
         assertEq(borrowTrue, borrowToTest, "Diff in snippets vs integration borrowAPY test");
     }
 
+    function testBorrowAPYIdleMarket(Market memory market) public {
+        MarketParams memory idleMarket;
+        idleMarket.loanToken = address(loanToken);
+
+        uint256 borrowRate = snippets.borrowAPY(idleMarket, market);
+
+        assertEq(borrowRate, 0, "borrow rate");
+    }
+
     function testSupplyAPYEqual0(Market memory market) public {
         vm.assume(market.totalBorrowAssets == 0);
         vm.assume(market.totalSupplyAssets > 100000);
diff --git a/test/forge/metamorpho/TestMetaMorphoSnippets.sol b/test/forge/metamorpho/TestMetaMorphoSnippets.sol
index cf3bd00..13e51ae 100644
--- a/test/forge/metamorpho/TestMetaMorphoSnippets.sol
+++ b/test/forge/metamorpho/TestMetaMorphoSnippets.sol
@@ -157,6 +157,21 @@ contract TestMetaMorphoSnippets is IntegrationTest {
         assertEq(snippets.supplyAPYMarket(marketParams, market), 0, "Diff in snippets vs integration supplyAPY test");
     }
 
+    function testSupplyAPYIdleMarket() public {
+        Market memory market;
+        MarketParams memory idleMarket;
+        idleMarket.loanToken = address(loanToken);
+
+        vm.prank(MORPHO_OWNER);
+        morpho.enableIrm(address(0));
+
+        morpho.createMarket(idleMarket);
+
+        uint256 supplyAPY = snippets.supplyAPYMarket(idleMarket, market);
+
+        assertEq(supplyAPY, 0, "supply APY");
+    }
+
     function testSupplyAPYMarket(Market memory market) public {
         vm.assume(market.totalBorrowAssets > 0);
         vm.assume(market.totalBorrowShares > 0);