From 6a65b1a395bf04ed4a05c314264b0b346cbab99b Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 12:18:26 -0400
Subject: [PATCH 01/12] implementation

---
 contracts/libraries/Allowance.sol         | 28 +++++++++++++++++++++++
 contracts/p0/mixins/Trading.sol           |  9 ++++++--
 contracts/p1/mixins/Trading.sol           |  9 ++++++--
 contracts/plugins/trading/GnosisTrade.sol | 10 +++++---
 4 files changed, 49 insertions(+), 7 deletions(-)
 create mode 100644 contracts/libraries/Allowance.sol

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
new file mode 100644
index 0000000000..86eb2d73e4
--- /dev/null
+++ b/contracts/libraries/Allowance.sol
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: BlueOak-1.0.0
+pragma solidity 0.8.19;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+library AllowanceLib {
+    /// An approve helper that:
+    ///   1. Sets initial allowance to 0
+    ///   2. Tries to set the provided allowance
+    ///   3. Falls back to setting a maximum allowance, if (2) fails
+    function safeApproveFallbackToMax(
+        IERC20 token,
+        address spender,
+        uint256 value
+    ) internal {
+        // 1. Set initial allowance to 0
+        require(token.approve(spender, 0), "failed to set 0 allowance");
+
+        // 2. Try to set the provided allowance
+        bool success; // bool success = false;
+        try token.approve(spender, value) returns (bool _success) {
+            success = _success;
+        } catch {}
+
+        // 3. Fall-back to setting a maximum allowance
+        if (!success) token.approve(spender, type(uint256).max);
+    }
+}
diff --git a/contracts/p0/mixins/Trading.sol b/contracts/p0/mixins/Trading.sol
index b49aee3f11..d0c5f7496f 100644
--- a/contracts/p0/mixins/Trading.sol
+++ b/contracts/p0/mixins/Trading.sol
@@ -6,6 +6,7 @@ import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "../../interfaces/IBroker.sol";
 import "../../interfaces/IMain.sol";
 import "../../interfaces/ITrade.sol";
+import "../../libraries/Allowance.sol";
 import "../../libraries/Fixed.sol";
 import "./Rewardable.sol";
 
@@ -68,8 +69,12 @@ abstract contract TradingP0 is RewardableP0, ITrading {
         IBroker broker = main.broker();
         assert(address(trades[req.sell.erc20()]) == address(0));
 
-        req.sell.erc20().safeApprove(address(broker), 0);
-        req.sell.erc20().safeApprove(address(broker), req.sellAmount);
+        // Set allowance via custom approval -- first sets allowance to 0, then sets allowance
+        // to either the requested amount or the maximum possible amount, if that fails.
+        //
+        // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
+        // amount is > 0 and < type(uint256).max.
+        AllowanceLib.safeApproveFallbackToMax(req.sell.erc20(), address(broker), req.sellAmount);
 
         trade = broker.openTrade(kind, req, prices);
         trades[req.sell.erc20()] = trade;
diff --git a/contracts/p1/mixins/Trading.sol b/contracts/p1/mixins/Trading.sol
index 863f7ab113..9c8daba201 100644
--- a/contracts/p1/mixins/Trading.sol
+++ b/contracts/p1/mixins/Trading.sol
@@ -7,6 +7,7 @@ import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "@openzeppelin/contracts/utils/Multicall.sol";
 import "../../interfaces/ITrade.sol";
 import "../../interfaces/ITrading.sol";
+import "../../libraries/Allowance.sol";
 import "../../libraries/Fixed.sol";
 import "./Component.sol";
 import "./RewardableLib.sol";
@@ -120,8 +121,12 @@ abstract contract TradingP1 is Multicall, ComponentP1, ReentrancyGuardUpgradeabl
         IERC20 sell = req.sell.erc20();
         assert(address(trades[sell]) == address(0));
 
-        IERC20Upgradeable(address(sell)).safeApprove(address(broker), 0);
-        IERC20Upgradeable(address(sell)).safeApprove(address(broker), req.sellAmount);
+        // Set allowance via custom approval -- first sets allowance to 0, then sets allowance
+        // to either the requested amount or the maximum possible amount, if that fails.
+        //
+        // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
+        // amount is > 0 and < type(uint256).max.
+        AllowanceLib.safeApproveFallbackToMax(req.sell.erc20(), address(broker), req.sellAmount);
 
         trade = broker.openTrade(kind, req, prices);
         trades[sell] = trade;
diff --git a/contracts/plugins/trading/GnosisTrade.sol b/contracts/plugins/trading/GnosisTrade.sol
index e8413c5fea..25b9c1ba44 100644
--- a/contracts/plugins/trading/GnosisTrade.sol
+++ b/contracts/plugins/trading/GnosisTrade.sol
@@ -4,6 +4,7 @@ pragma solidity 0.8.19;
 import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
 import "@openzeppelin/contracts/utils/math/Math.sol";
 import "@openzeppelin/contracts-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol";
+import "../../libraries/Allowance.sol";
 import "../../libraries/Fixed.sol";
 import "../../interfaces/IBroker.sol";
 import "../../interfaces/IGnosis.sol";
@@ -130,9 +131,12 @@ contract GnosisTrade is ITrade {
 
         // == Interactions ==
 
-        // Set allowance (two safeApprove calls to support USDT)
-        IERC20Upgradeable(address(sell)).safeApprove(address(gnosis), 0);
-        IERC20Upgradeable(address(sell)).safeApprove(address(gnosis), initBal);
+        // Set allowance via custom approval -- first sets allowance to 0, then sets allowance
+        // to either the requested amount or the maximum possible amount, if that fails.
+        //
+        // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
+        // amount is > 0 and < type(uint256).max.
+        AllowanceLib.safeApproveFallbackToMax(sell, address(gnosis), initBal);
 
         auctionId = gnosis.initiateAuction(
             sell,

From a4d95470041209ee0e1d66dca34598755723f86d Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 12:19:18 -0400
Subject: [PATCH 02/12] CHANGELOG

---
 CHANGELOG.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0c40e6a6de..693d32bd91 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+# 3.0.1
+
+### Upgrade steps
+
+Update `BackingManager`, both `RevenueTraders` (rTokenTrader/rsrTrader), and call `Broker.setBatchTradeImplementation()` passing in the new `GnosisTrade` address.
+
 # 3.0.0
 
 ### Upgrade Steps

From 700f202c9730f1eb8123b45deb52a463ae40d799 Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 12:23:20 -0400
Subject: [PATCH 03/12] implementation nits

---
 contracts/libraries/Allowance.sol | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
index 86eb2d73e4..de5e20bb2e 100644
--- a/contracts/libraries/Allowance.sol
+++ b/contracts/libraries/Allowance.sol
@@ -8,6 +8,8 @@ library AllowanceLib {
     ///   1. Sets initial allowance to 0
     ///   2. Tries to set the provided allowance
     ///   3. Falls back to setting a maximum allowance, if (2) fails
+    /// Context: Some new-age ERC20s think it's a good idea to revert for allowances
+    /// that are > 0 but < type(uint256).max.
     function safeApproveFallbackToMax(
         IERC20 token,
         address spender,
@@ -16,6 +18,8 @@ library AllowanceLib {
         // 1. Set initial allowance to 0
         require(token.approve(spender, 0), "failed to set 0 allowance");
 
+        if (value == 0) return;
+
         // 2. Try to set the provided allowance
         bool success; // bool success = false;
         try token.approve(spender, value) returns (bool _success) {

From 5ee29e362be0287e98a79b12552ef260c1f30e84 Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 12:42:57 -0400
Subject: [PATCH 04/12] add regression test, confirmed fails on previous code

---
 contracts/plugins/mocks/BadERC20.sol | 10 ++++++++++
 test/scenario/BadERC20.test.ts       | 24 ++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/contracts/plugins/mocks/BadERC20.sol b/contracts/plugins/mocks/BadERC20.sol
index 99c7791e84..11570a4e4c 100644
--- a/contracts/plugins/mocks/BadERC20.sol
+++ b/contracts/plugins/mocks/BadERC20.sol
@@ -11,6 +11,7 @@ contract BadERC20 is ERC20Mock {
     uint8 private _decimals;
     uint192 public transferFee; // {1}
     bool public revertDecimals;
+    bool public revertApprove; // if true, reverts for any approve > 0 and < type(uint256).max
 
     mapping(address => bool) public censored;
 
@@ -34,6 +35,10 @@ contract BadERC20 is ERC20Mock {
         censored[account] = val;
     }
 
+    function setRevertApprove(bool newRevertApprove) external {
+        revertApprove = newRevertApprove;
+    }
+
     function decimals() public view override returns (uint8) {
         bytes memory data = abi.encodePacked((bytes4(keccak256("absentDecimalsFn()"))));
 
@@ -42,6 +47,11 @@ contract BadERC20 is ERC20Mock {
         return _decimals;
     }
 
+    function approve(address spender, uint256 amount) public virtual override returns (bool) {
+        if (revertApprove && amount > 0 && amount < type(uint256).max) revert("revertApprove");
+        return super.approve(spender, amount);
+    }
+
     function transfer(address to, uint256 amount) public virtual override returns (bool) {
         address owner = _msgSender();
         if (censored[owner] || censored[to]) revert("censored");
diff --git a/test/scenario/BadERC20.test.ts b/test/scenario/BadERC20.test.ts
index 6874a021ca..13adebdcdd 100644
--- a/test/scenario/BadERC20.test.ts
+++ b/test/scenario/BadERC20.test.ts
@@ -396,4 +396,28 @@ describe(`Bad ERC20 - P${IMPLEMENTATION}`, () => {
         )
     })
   })
+
+  describe('with fussy approvals', function () {
+    let issueAmt: BigNumber
+
+    beforeEach(async () => {
+      issueAmt = initialBal.div(100)
+      await token0.connect(addr1).approve(rToken.address, issueAmt)
+      await token0.setRevertApprove(true)
+      await rToken.connect(addr1).issue(issueAmt)
+    })
+
+    it('Regression test wcUSDCv3 10/10/2023 -- should not revert during recollateralization', async () => {
+      await basketHandler.setPrimeBasket(
+        [token0.address, backupToken.address],
+        [fp('0.5'), fp('0.5')]
+      )
+      await basketHandler.refreshBasket()
+
+      // Should launch recollateralization auction successfully
+      await expect(backingManager.rebalance(TradeKind.BATCH_AUCTION))
+        .to.emit(backingManager, 'TradeStarted')
+        .withArgs(anyValue, token0.address, backupToken.address, anyValue, anyValue)
+    })
+  })
 })

From 3b2b5796afece36c6de1341f5ba97122f3cc2854 Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 12:48:07 -0400
Subject: [PATCH 05/12] slightly better implementation

---
 contracts/libraries/Allowance.sol | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
index de5e20bb2e..b8da24064b 100644
--- a/contracts/libraries/Allowance.sol
+++ b/contracts/libraries/Allowance.sol
@@ -16,17 +16,24 @@ library AllowanceLib {
         uint256 value
     ) internal {
         // 1. Set initial allowance to 0
-        require(token.approve(spender, 0), "failed to set 0 allowance");
+        token.approve(spender, 0);
+        require(token.allowance(address(this), spender) == 0, "allowance not 0");
 
         if (value == 0) return;
 
         // 2. Try to set the provided allowance
         bool success; // bool success = false;
-        try token.approve(spender, value) returns (bool _success) {
-            success = _success;
+        try token.approve(spender, value) returns (bool) {
+            success = token.allowance(address(this), spender) == value;
         } catch {}
 
         // 3. Fall-back to setting a maximum allowance
-        if (!success) token.approve(spender, type(uint256).max);
+        if (!success) {
+            token.approve(spender, type(uint256).max);
+            require(
+                token.allowance(address(this), spender) == type(uint256).max,
+                "allowance not max"
+            );
+        }
     }
 }

From 233eec6934874580b53d8c159930484c94a92e27 Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 12:58:34 -0400
Subject: [PATCH 06/12] add documentation comment to
 RevenueTrader._distributeTokenToBuy()

---
 contracts/p0/RevenueTrader.sol | 3 +++
 contracts/p1/RevenueTrader.sol | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/contracts/p0/RevenueTrader.sol b/contracts/p0/RevenueTrader.sol
index 2f380927fe..a62cf8bd18 100644
--- a/contracts/p0/RevenueTrader.sol
+++ b/contracts/p0/RevenueTrader.sol
@@ -130,6 +130,9 @@ contract RevenueTraderP0 is TradingP0, IRevenueTrader {
         uint256 bal = tokenToBuy.balanceOf(address(this));
         tokenToBuy.safeApprove(address(main.distributor()), 0);
         tokenToBuy.safeApprove(address(main.distributor()), bal);
+        // do not need to use AllowanceLib.safeApproveFallbackToCustom here because
+        // tokenToBuy can be assumed to be either RSR or the RToken
+
         main.distributor().distribute(tokenToBuy, bal);
     }
 }
diff --git a/contracts/p1/RevenueTrader.sol b/contracts/p1/RevenueTrader.sol
index fe7b409b50..43253c6b0e 100644
--- a/contracts/p1/RevenueTrader.sol
+++ b/contracts/p1/RevenueTrader.sol
@@ -179,6 +179,9 @@ contract RevenueTraderP1 is TradingP1, IRevenueTrader {
         uint256 bal = tokenToBuy.balanceOf(address(this));
         tokenToBuy.safeApprove(address(distributor), 0);
         tokenToBuy.safeApprove(address(distributor), bal);
+
+        // do not need to use AllowanceLib.safeApproveFallbackToCustom here because
+        // tokenToBuy can be assumed to be either RSR or the RToken
         distributor.distribute(tokenToBuy, bal);
     }
 

From 61079639ce6d6d13c98ad59fcd458d0e1b62ae7d Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 13:02:09 -0400
Subject: [PATCH 07/12] add second regression test for revenue auctions

---
 test/scenario/BadERC20.test.ts | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/test/scenario/BadERC20.test.ts b/test/scenario/BadERC20.test.ts
index 13adebdcdd..220ed60d0f 100644
--- a/test/scenario/BadERC20.test.ts
+++ b/test/scenario/BadERC20.test.ts
@@ -407,17 +407,28 @@ describe(`Bad ERC20 - P${IMPLEMENTATION}`, () => {
       await rToken.connect(addr1).issue(issueAmt)
     })
 
-    it('Regression test wcUSDCv3 10/10/2023 -- should not revert during recollateralization', async () => {
-      await basketHandler.setPrimeBasket(
-        [token0.address, backupToken.address],
-        [fp('0.5'), fp('0.5')]
-      )
-      await basketHandler.refreshBasket()
-
-      // Should launch recollateralization auction successfully
-      await expect(backingManager.rebalance(TradeKind.BATCH_AUCTION))
-        .to.emit(backingManager, 'TradeStarted')
-        .withArgs(anyValue, token0.address, backupToken.address, anyValue, anyValue)
+    context('Regression tests wcUSDCv3 10/10/2023', () => {
+      it('should not revert during recollateralization', async () => {
+        await basketHandler.setPrimeBasket(
+          [token0.address, backupToken.address],
+          [fp('0.5'), fp('0.5')]
+        )
+        await basketHandler.refreshBasket()
+
+        // Should launch recollateralization auction successfully
+        await expect(backingManager.rebalance(TradeKind.BATCH_AUCTION))
+          .to.emit(backingManager, 'TradeStarted')
+          .withArgs(anyValue, token0.address, backupToken.address, anyValue, anyValue)
+      })
+
+      it('should not revert during revenue auction', async () => {
+        await token0.mint(rsrTrader.address, issueAmt)
+
+        // Should launch revenue auction successfully
+        await expect(rsrTrader.manageTokens([token0.address], [TradeKind.BATCH_AUCTION]))
+          .to.emit(rsrTrader, 'TradeStarted')
+          .withArgs(anyValue, token0.address, rsr.address, anyValue, anyValue)
+      })
     })
   })
 })

From 1f49f794e5431f011b4524173cfef9bf9726ef6a Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Tue, 10 Oct 2023 15:31:54 -0400
Subject: [PATCH 08/12] slight tweak to implementation to account for ERC20s
 that do not handle max allowances the same way

---
 contracts/libraries/Allowance.sol | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
index b8da24064b..e0855f6af2 100644
--- a/contracts/libraries/Allowance.sol
+++ b/contracts/libraries/Allowance.sol
@@ -30,10 +30,7 @@ library AllowanceLib {
         // 3. Fall-back to setting a maximum allowance
         if (!success) {
             token.approve(spender, type(uint256).max);
-            require(
-                token.allowance(address(this), spender) == type(uint256).max,
-                "allowance not max"
-            );
+            require(token.allowance(address(this), spender) >= value, "allowance missing");
         }
     }
 }

From ded1f1f8045103ff98f3ec3aaf9f3227f37097db Mon Sep 17 00:00:00 2001
From: Akshat Mittal <itsreallyakshat@gmail.com>
Date: Wed, 11 Oct 2023 15:57:08 +0530
Subject: [PATCH 09/12] Additional fix for USDT-like tokens with no return
 value

---
 contracts/libraries/Allowance.sol         | 12 +++++++++---
 contracts/p0/mixins/Trading.sol           |  6 +++++-
 contracts/p1/mixins/Trading.sol           |  6 +++++-
 contracts/plugins/trading/GnosisTrade.sol |  2 +-
 hardhat.config.ts                         |  2 +-
 5 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
index e0855f6af2..849fa3f1da 100644
--- a/contracts/libraries/Allowance.sol
+++ b/contracts/libraries/Allowance.sol
@@ -1,7 +1,11 @@
 // SPDX-License-Identifier: BlueOak-1.0.0
 pragma solidity 0.8.19;
 
-import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+interface IERC20ApproveOnly {
+    function approve(address spender, uint256 value) external;
+
+    function allowance(address owner, address spender) external view returns (uint256);
+}
 
 library AllowanceLib {
     /// An approve helper that:
@@ -11,10 +15,12 @@ library AllowanceLib {
     /// Context: Some new-age ERC20s think it's a good idea to revert for allowances
     /// that are > 0 but < type(uint256).max.
     function safeApproveFallbackToMax(
-        IERC20 token,
+        address token_address,
         address spender,
         uint256 value
     ) internal {
+        IERC20ApproveOnly token = IERC20ApproveOnly(token_address);
+
         // 1. Set initial allowance to 0
         token.approve(spender, 0);
         require(token.allowance(address(this), spender) == 0, "allowance not 0");
@@ -23,7 +29,7 @@ library AllowanceLib {
 
         // 2. Try to set the provided allowance
         bool success; // bool success = false;
-        try token.approve(spender, value) returns (bool) {
+        try token.approve(spender, value) {
             success = token.allowance(address(this), spender) == value;
         } catch {}
 
diff --git a/contracts/p0/mixins/Trading.sol b/contracts/p0/mixins/Trading.sol
index d0c5f7496f..52fc993eea 100644
--- a/contracts/p0/mixins/Trading.sol
+++ b/contracts/p0/mixins/Trading.sol
@@ -74,7 +74,11 @@ abstract contract TradingP0 is RewardableP0, ITrading {
         //
         // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
         // amount is > 0 and < type(uint256).max.
-        AllowanceLib.safeApproveFallbackToMax(req.sell.erc20(), address(broker), req.sellAmount);
+        AllowanceLib.safeApproveFallbackToMax(
+            address(req.sell.erc20()),
+            address(broker),
+            req.sellAmount
+        );
 
         trade = broker.openTrade(kind, req, prices);
         trades[req.sell.erc20()] = trade;
diff --git a/contracts/p1/mixins/Trading.sol b/contracts/p1/mixins/Trading.sol
index 9c8daba201..8801c0e6dc 100644
--- a/contracts/p1/mixins/Trading.sol
+++ b/contracts/p1/mixins/Trading.sol
@@ -126,7 +126,11 @@ abstract contract TradingP1 is Multicall, ComponentP1, ReentrancyGuardUpgradeabl
         //
         // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
         // amount is > 0 and < type(uint256).max.
-        AllowanceLib.safeApproveFallbackToMax(req.sell.erc20(), address(broker), req.sellAmount);
+        AllowanceLib.safeApproveFallbackToMax(
+            address(req.sell.erc20()),
+            address(broker),
+            req.sellAmount
+        );
 
         trade = broker.openTrade(kind, req, prices);
         trades[sell] = trade;
diff --git a/contracts/plugins/trading/GnosisTrade.sol b/contracts/plugins/trading/GnosisTrade.sol
index 25b9c1ba44..9f52e6387a 100644
--- a/contracts/plugins/trading/GnosisTrade.sol
+++ b/contracts/plugins/trading/GnosisTrade.sol
@@ -136,7 +136,7 @@ contract GnosisTrade is ITrade {
         //
         // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
         // amount is > 0 and < type(uint256).max.
-        AllowanceLib.safeApproveFallbackToMax(sell, address(gnosis), initBal);
+        AllowanceLib.safeApproveFallbackToMax(address(sell), address(gnosis), initBal);
 
         auctionId = gnosis.initiateAuction(
             sell,
diff --git a/hardhat.config.ts b/hardhat.config.ts
index 7b540748d4..9dddd006bf 100644
--- a/hardhat.config.ts
+++ b/hardhat.config.ts
@@ -38,7 +38,7 @@ const config: HardhatUserConfig = {
       // network for tests/in-process stuff
       forking: useEnv('FORK')
         ? {
-            url: forkRpcs[(useEnv('FORK_NETWORK') ?? 'mainnet') as Network],
+            url: forkRpcs[useEnv('FORK_NETWORK', 'mainnet') as Network],
             blockNumber: Number(useEnv(`FORK_BLOCK`, forkBlockNumber['default'].toString())),
           }
         : undefined,

From 9c7803691f67bd9d4c8c727fe5e59916af537127 Mon Sep 17 00:00:00 2001
From: Akshat Mittal <itsreallyakshat@gmail.com>
Date: Wed, 11 Oct 2023 16:01:32 +0530
Subject: [PATCH 10/12] Make linter happy

---
 contracts/libraries/Allowance.sol | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
index 849fa3f1da..c383ee7f8b 100644
--- a/contracts/libraries/Allowance.sol
+++ b/contracts/libraries/Allowance.sol
@@ -15,11 +15,11 @@ library AllowanceLib {
     /// Context: Some new-age ERC20s think it's a good idea to revert for allowances
     /// that are > 0 but < type(uint256).max.
     function safeApproveFallbackToMax(
-        address token_address,
+        address tokenAddress,
         address spender,
         uint256 value
     ) internal {
-        IERC20ApproveOnly token = IERC20ApproveOnly(token_address);
+        IERC20ApproveOnly token = IERC20ApproveOnly(tokenAddress);
 
         // 1. Set initial allowance to 0
         token.approve(spender, 0);

From a1b2be1b344cd30381048bb146e749956e8d77ad Mon Sep 17 00:00:00 2001
From: Patrick McKelvy <pmckelvy1@gmail.com>
Date: Wed, 11 Oct 2023 09:58:28 -0400
Subject: [PATCH 11/12] gas opt.

---
 contracts/p1/mixins/Trading.sol | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contracts/p1/mixins/Trading.sol b/contracts/p1/mixins/Trading.sol
index 8801c0e6dc..12c8f115bf 100644
--- a/contracts/p1/mixins/Trading.sol
+++ b/contracts/p1/mixins/Trading.sol
@@ -127,7 +127,7 @@ abstract contract TradingP1 is Multicall, ComponentP1, ReentrancyGuardUpgradeabl
         // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
         // amount is > 0 and < type(uint256).max.
         AllowanceLib.safeApproveFallbackToMax(
-            address(req.sell.erc20()),
+            address(sell),
             address(broker),
             req.sellAmount
         );

From 59565d2d40d59273b7ba0e7972fa8e9fa965617e Mon Sep 17 00:00:00 2001
From: Taylor Brent <taylor.w.brent@gmail.com>
Date: Wed, 11 Oct 2023 10:04:02 -0400
Subject: [PATCH 12/12] lint clean

---
 contracts/libraries/Allowance.sol | 1 +
 contracts/p1/mixins/Trading.sol   | 6 +-----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/contracts/libraries/Allowance.sol b/contracts/libraries/Allowance.sol
index c383ee7f8b..c3e5f62e5d 100644
--- a/contracts/libraries/Allowance.sol
+++ b/contracts/libraries/Allowance.sol
@@ -31,6 +31,7 @@ library AllowanceLib {
         bool success; // bool success = false;
         try token.approve(spender, value) {
             success = token.allowance(address(this), spender) == value;
+            // solhint-disable-next-line no-empty-blocks
         } catch {}
 
         // 3. Fall-back to setting a maximum allowance
diff --git a/contracts/p1/mixins/Trading.sol b/contracts/p1/mixins/Trading.sol
index 12c8f115bf..24b2044d38 100644
--- a/contracts/p1/mixins/Trading.sol
+++ b/contracts/p1/mixins/Trading.sol
@@ -126,11 +126,7 @@ abstract contract TradingP1 is Multicall, ComponentP1, ReentrancyGuardUpgradeabl
         //
         // Context: wcUSDCv3 has a non-standard approve() function that reverts if the approve
         // amount is > 0 and < type(uint256).max.
-        AllowanceLib.safeApproveFallbackToMax(
-            address(sell),
-            address(broker),
-            req.sellAmount
-        );
+        AllowanceLib.safeApproveFallbackToMax(address(sell), address(broker), req.sellAmount);
 
         trade = broker.openTrade(kind, req, prices);
         trades[sell] = trade;