From eeb09d74a075c5b5351b36e90d9f6807f813de77 Mon Sep 17 00:00:00 2001
From: Jeff Wu <jeff@notional.finance>
Date: Tue, 28 Nov 2023 14:56:02 -0800
Subject: [PATCH] fix: check if get actual supply exists

---
 contracts/vaults/BalancerWeightedAuraVault.sol | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/contracts/vaults/BalancerWeightedAuraVault.sol b/contracts/vaults/BalancerWeightedAuraVault.sol
index b6488d13..325ea67a 100644
--- a/contracts/vaults/BalancerWeightedAuraVault.sol
+++ b/contracts/vaults/BalancerWeightedAuraVault.sol
@@ -91,4 +91,19 @@ contract BalancerWeightedAuraVault is AuraStakingMixin {
 
         return _calculateLPTokenValue(balances, spotPrices);
     }
+
+    /// @notice Weighted pools may have pre-minted BPT. If that is the case then
+    /// we need to call getActualSupply() instead. Legacy pools do not have the
+    /// getActualSupply method. See:
+    /// https://docs.balancer.fi/concepts/advanced/valuing-bpt/valuing-bpt.html#getting-bpt-supply
+    function _totalPoolSupply() internal view override returns (uint256) {
+        // As of this writing the documentation linked above appears inaccurate and the
+        // pre-minted total supply returned by a pool is not a fixed constant. Therefore,
+        // we use a try / catch here instead.
+        try IComposablePool(address(BALANCER_POOL_TOKEN)).getActualSupply() returns (uint256 totalSupply) {
+            return totalSupply;
+        } catch {
+            return super._totalPoolSupply();
+        }
+    }
 }
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