From a3d1a7c9bd763a3e26447748f8b8ee1a0b5f31d6 Mon Sep 17 00:00:00 2001
From: cwang25 <hans@compound.finance>
Date: Thu, 11 Nov 2021 10:19:10 -0800
Subject: [PATCH 1/2] fix #15. Changes the uses of getUnderlyingPrice, name,
 symbol to try_getUnderlyingPrice, try_name, try_symbol...etc

---
 src/mappings/markets.ts | 48 ++++++++++++++++++++++++-----------------
 subgraph.yaml           |  2 +-
 2 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/src/mappings/markets.ts b/src/mappings/markets.ts
index 6d3dfdb..4cbf996 100644
--- a/src/mappings/markets.ts
+++ b/src/mappings/markets.ts
@@ -53,10 +53,11 @@ function getTokenPrice(
     let mantissaDecimalFactor = 18 - underlyingDecimals + 18
     let bdFactor = exponentToBigDecimal(mantissaDecimalFactor)
     let oracle2 = PriceOracle2.bind(oracleAddress)
-    underlyingPrice = oracle2
-      .getUnderlyingPrice(eventAddress)
-      .toBigDecimal()
-      .div(bdFactor)
+    let tryPrice = oracle2.try_getUnderlyingPrice(eventAddress)
+
+    underlyingPrice = tryPrice.reverted
+      ? zeroBD
+      : tryPrice.value.toBigDecimal().div(bdFactor)
 
     /* PriceOracle(1) is used (only for the first ~100 blocks of Comptroller. Annoying but we must
      * handle this. We use it for more than 100 blocks, see reason at top of if statement
@@ -89,16 +90,18 @@ function getUSDCpriceETH(blockNumber: i32): BigDecimal {
     let oracle2 = PriceOracle2.bind(oracleAddress)
     let mantissaDecimalFactorUSDC = 18 - 6 + 18
     let bdFactorUSDC = exponentToBigDecimal(mantissaDecimalFactorUSDC)
-    usdPrice = oracle2
-      .getUnderlyingPrice(Address.fromString(cUSDCAddress))
-      .toBigDecimal()
-      .div(bdFactorUSDC)
+    let tryPrice = oracle2.try_getUnderlyingPrice(Address.fromString(cUSDCAddress))
+
+    usdPrice = tryPrice.reverted
+      ? zeroBD
+      : tryPrice.value.toBigDecimal().div(bdFactorUSDC)
   } else {
     let oracle1 = PriceOracle.bind(priceOracle1Address)
-    usdPrice = oracle1
-      .getPrice(Address.fromString(USDCAddress))
-      .toBigDecimal()
-      .div(mantissaFactorBD)
+    let tryPrice = oracle1.try_getPrice(Address.fromString(USDCAddress))
+
+    usdPrice = tryPrice.reverted
+      ? zeroBD
+      : tryPrice.value.toBigDecimal().div(mantissaFactorBD)
   }
   return usdPrice
 }
@@ -125,8 +128,10 @@ export function createMarket(marketAddress: string): Market {
     let underlyingContract = ERC20.bind(market.underlyingAddress as Address)
     market.underlyingDecimals = underlyingContract.decimals()
     if (market.underlyingAddress.toHexString() != daiAddress) {
-      market.underlyingName = underlyingContract.name()
-      market.underlyingSymbol = underlyingContract.symbol()
+      let tryname = underlyingContract.try_name()
+      let trysymbol = underlyingContract.try_symbol()
+      market.underlyingName = tryname.reverted ? '' : tryname.value
+      market.underlyingSymbol = trysymbol.reverted ? '' : trysymbol.value
     } else {
       market.underlyingName = 'Dai Stablecoin v1.0 (DAI)'
       market.underlyingSymbol = 'DAI'
@@ -148,10 +153,12 @@ export function createMarket(marketAddress: string): Market {
   market.interestRateModelAddress = interestRateModelAddress.reverted
     ? Address.fromString('0x0000000000000000000000000000000000000000')
     : interestRateModelAddress.value
-  market.name = contract.name()
+  let tryMarketName = contract.try_name()
+  market.name = tryMarketName.reverted ? '' : tryMarketName.value
   market.reserves = zeroBD
   market.supplyRate = zeroBD
-  market.symbol = contract.symbol()
+  let tryMarketSymbol = contract.try_symbol()
+  market.symbol = tryMarketSymbol.reverted ? '' : tryMarketSymbol.value
   market.totalBorrows = zeroBD
   market.totalSupply = zeroBD
 
@@ -168,10 +175,11 @@ function getETHinUSD(blockNumber: i32): BigDecimal {
   let comptroller = Comptroller.load('1')
   let oracleAddress = comptroller.priceOracle as Address
   let oracle = PriceOracle2.bind(oracleAddress)
-  let ethPriceInUSD = oracle
-    .getUnderlyingPrice(Address.fromString(cETHAddress))
-    .toBigDecimal()
-    .div(mantissaFactorBD)
+  let tryPrice = oracle.try_getUnderlyingPrice(Address.fromString(cETHAddress))
+
+  let ethPriceInUSD = tryPrice.reverted
+    ? zeroBD
+    : tryPrice.value.toBigDecimal().div(mantissaFactorBD)
   return ethPriceInUSD
 }
 
diff --git a/subgraph.yaml b/subgraph.yaml
index 01a6086..ef00e72 100644
--- a/subgraph.yaml
+++ b/subgraph.yaml
@@ -10,7 +10,7 @@ dataSources:
     source:
       address: "0x3d9819210A31b4961b30EF54bE2aeD79B9c9Cd3B"
       abi: Comptroller
-      startBlock: 7700000
+      startBlock: 10000000
     mapping:
       kind: ethereum/events
       apiVersion: 0.0.4

From 26be8550851853764bd6a968dfb84ed79b94f5f7 Mon Sep 17 00:00:00 2001
From: cwang25 <hans@compound.finance>
Date: Thu, 11 Nov 2021 10:24:37 -0800
Subject: [PATCH 2/2] revert starting block back to old value

---
 subgraph.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/subgraph.yaml b/subgraph.yaml
index ef00e72..01a6086 100644
--- a/subgraph.yaml
+++ b/subgraph.yaml
@@ -10,7 +10,7 @@ dataSources:
     source:
       address: "0x3d9819210A31b4961b30EF54bE2aeD79B9c9Cd3B"
       abi: Comptroller
-      startBlock: 10000000
+      startBlock: 7700000
     mapping:
       kind: ethereum/events
       apiVersion: 0.0.4