Nits for UI compatibility

contracts/src/external/Hyperdrive.sol

@@ -218,7 +218,7 @@ abstract contract Hyperdrive is
         uint256,
         IHyperdrive.Options calldata
     ) external payable returns (uint256) {
-        _delegate(target1);
+        _delegate(target3);
     }
 
     /// @inheritdoc IHyperdriveCore

contracts/src/external/HyperdriveTarget0.sol

@@ -406,6 +406,13 @@ abstract contract HyperdriveTarget0 is
         _revert(abi.encode(_perTokenApprovals[tokenId][account][spender]));
     }
 
+    /// @notice Gets the decimals of the MultiToken. This is the same as the
+    ///         decimals used by the base token.
+    /// @return The decimals of the MultiToken.
+    function decimals() external view virtual returns (uint8) {
+        _revert(abi.encode(_baseToken.decimals()));
+    }
+
     /// @notice Gets the name of a sub-token.
     /// @param tokenId The sub-token id.
     /// @return The name.

contracts/src/external/HyperdriveTarget1.sol

@@ -32,19 +32,6 @@ abstract contract HyperdriveTarget1 is
 
     /// LPs ///
 
-    /// @notice Allows the first LP to initialize the market with a target APR.
-    /// @param _contribution The amount of base to supply.
-    /// @param _apr The target APR.
-    /// @param _options The options that configure how the operation is settled.
-    /// @return lpShares The initial number of LP shares created.
-    function initialize(
-        uint256 _contribution,
-        uint256 _apr,
-        IHyperdrive.Options calldata _options
-    ) external payable returns (uint256 lpShares) {
-        return _initialize(_contribution, _apr, _options);
-    }
-
     /// @notice Allows LPs to supply liquidity for LP shares.
     /// @param _contribution The amount of base to supply.
     /// @param _minLpSharePrice The minimum LP share price the LP is willing

contracts/src/external/HyperdriveTarget3.sol

@@ -30,6 +30,21 @@ abstract contract HyperdriveTarget3 is
         IHyperdrive.PoolConfig memory _config
     ) HyperdriveStorage(_config) {}
 
+    /// LPs ///
+
+    /// @notice Allows the first LP to initialize the market with a target APR.
+    /// @param _contribution The amount of base to supply.
+    /// @param _apr The target APR.
+    /// @param _options The options that configure how the operation is settled.
+    /// @return lpShares The initial number of LP shares created.
+    function initialize(
+        uint256 _contribution,
+        uint256 _apr,
+        IHyperdrive.Options calldata _options
+    ) external payable returns (uint256 lpShares) {
+        return _initialize(_contribution, _apr, _options);
+    }
+
     /// Longs ///
 
     /// @notice Opens a long position.

contracts/src/instances/steth/StETHTarget0.sol

@@ -67,4 +67,10 @@ contract StETHTarget0 is HyperdriveTarget0, StETHBase {
     function lido() external view returns (ILido) {
         _revert(abi.encode(_lido));
     }
+
+    /// @notice Returns the MultiToken's decimals.
+    /// @return The MultiToken's decimals.
+    function decimals() external pure override returns (uint8) {
+        _revert(abi.encode(uint8(18)));
+    }
 }

contracts/src/interfaces/IHyperdriveEvents.sol

@@ -9,7 +9,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         address indexed provider,
         uint256 lpAmount,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 apr
     );
 
@@ -18,7 +19,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         address indexed provider,
         uint256 lpAmount,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 lpSharePrice
     );
 
@@ -27,7 +29,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         address indexed provider,
         uint256 lpAmount,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 withdrawalShareAmount,
         uint256 lpSharePrice
     );
@@ -37,7 +40,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         address indexed provider,
         uint256 withdrawalShareAmount,
         uint256 baseAmount,
-        uint256 vaultSharePrice
+        uint256 vaultShareAmount,
+        bool asBase
     );
 
     /// @notice Emitted when a long position is opened.
@@ -46,7 +50,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         uint256 indexed assetId,
         uint256 maturityTime,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 bondAmount
     );
 
@@ -56,7 +61,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         uint256 indexed assetId,
         uint256 maturityTime,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 bondAmount
     );
 
@@ -66,7 +72,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         uint256 indexed assetId,
         uint256 maturityTime,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 bondAmount
     );
 
@@ -76,7 +83,8 @@ interface IHyperdriveEvents is IMultiTokenEvents {
         uint256 indexed assetId,
         uint256 maturityTime,
         uint256 baseAmount,
-        uint256 vaultSharePrice,
+        uint256 vaultShareAmount,
+        bool asBase,
         uint256 bondAmount
     );
 

contracts/src/interfaces/IMultiTokenRead.sol

@@ -2,6 +2,10 @@
 pragma solidity 0.8.20;
 
 interface IMultiTokenRead {
+    /// @notice Gets the decimals of the MultiToken.
+    /// @return The decimals of the MultiToken.
+    function decimals() external view returns (uint8);
+
     /// @notice Gets the name of the MultiToken.
     /// @return The name of the MultiToken.
     function name(uint256 id) external view returns (string memory);

contracts/src/internal/HyperdriveBase.sol

@@ -599,6 +599,25 @@ abstract contract HyperdriveBase is IHyperdriveEvents, HyperdriveStorage {
         }
     }
 
+    /// @dev Converts input to vault shares if necessary according to what is
+    ///      specified in options.
+    /// @param _amount The amount to convert.
+    /// @param _vaultSharePrice The current vault share price.
+    /// @param _options The options that configure the conversion.
+    /// @return The converted amount.
+    function _convertToVaultSharesFromOption(
+        uint256 _amount,
+        uint256 _vaultSharePrice,
+        IHyperdrive.Options calldata _options
+    ) internal pure returns (uint256) {
+        if (_options.asBase) {
+            // NOTE: Round down to underestimate the vault share amount.
+            return _amount.divDown(_vaultSharePrice);
+        } else {
+            return _amount;
+        }
+    }
+
     /// @dev Converts input to what is specified in the options from base.
     /// @param _amount The amount to convert.
     /// @param _vaultSharePrice The current vault share price.

contracts/src/internal/HyperdriveLP.sol

@@ -107,7 +107,8 @@ abstract contract HyperdriveLP is
             _options.destination,
             lpShares,
             baseContribution,
-            vaultSharePrice,
+            vaultShares,
+            _options.asBase,
             _apr
         );
 
@@ -239,7 +240,8 @@ abstract contract HyperdriveLP is
             _options.destination,
             lpShares,
             baseContribution,
-            vaultSharePrice,
+            vaultShares,
+            _options.asBase,
             lpSharePrice
         );
     }
@@ -297,16 +299,16 @@ abstract contract HyperdriveLP is
         withdrawalShares = _lpShares - withdrawalSharesRedeemed;
 
         // Emit a RemoveLiquidity event.
-        uint256 baseProceeds = _convertToBaseFromOption(
-            proceeds,
-            vaultSharePrice,
-            _options
-        );
         emit RemoveLiquidity(
             _options.destination,
             _lpShares,
-            baseProceeds,
-            vaultSharePrice,
+            _convertToBaseFromOption(proceeds, vaultSharePrice, _options),
+            _convertToVaultSharesFromOption(
+                proceeds,
+                vaultSharePrice,
+                _options
+            ),
+            _options.asBase,
             uint256(withdrawalShares),
             _calculateLPSharePrice(vaultSharePrice)
         );
@@ -351,16 +353,16 @@ abstract contract HyperdriveLP is
         );
 
         // Emit a RedeemWithdrawalShares event.
-        uint256 baseProceeds = _convertToBaseFromOption(
-            proceeds,
-            vaultSharePrice,
-            _options
-        );
         emit RedeemWithdrawalShares(
             _options.destination,
             withdrawalSharesRedeemed,
-            baseProceeds,
-            vaultSharePrice
+            _convertToBaseFromOption(proceeds, vaultSharePrice, _options),
+            _convertToVaultSharesFromOption(
+                proceeds,
+                vaultSharePrice,
+                _options
+            ),
+            _options.asBase
         );
 
         return (proceeds, withdrawalSharesRedeemed);

contracts/src/internal/HyperdriveLong.sol

@@ -114,18 +114,21 @@ abstract contract HyperdriveLong is IHyperdriveEvents, HyperdriveLP {
 
         // Emit an OpenLong event.
         uint256 amount = _amount; // Avoid stack too deep error.
+        uint256 maturityTime_ = maturityTime; // Avoid stack too deep error.
+        uint256 bondProceeds_ = bondProceeds; // Avoid stack too deep error.
+        uint256 vaultSharePrice_ = vaultSharePrice; // Avoid stack too deep error.
         IHyperdrive.Options calldata options = _options; // Avoid stack too deep error.
-        uint256 _bondProceeds = bondProceeds; // Avoid stack too deep error.
         emit OpenLong(
-            _options.destination,
+            options.destination,
             assetId,
-            maturityTime,
-            _convertToBaseFromOption(amount, vaultSharePrice, options),
-            vaultSharePrice,
-            _bondProceeds
+            maturityTime_,
+            _convertToBaseFromOption(amount, vaultSharePrice_, options),
+            _convertToVaultSharesFromOption(amount, vaultSharePrice_, options),
+            options.asBase,
+            bondProceeds_
         );
 
-        return (maturityTime, _bondProceeds);
+        return (maturityTime, bondProceeds_);
     }
 
     /// @dev Closes a long position with a specified maturity time.
@@ -218,12 +221,19 @@ abstract contract HyperdriveLong is IHyperdriveEvents, HyperdriveLP {
 
         // Emit a CloseLong event.
         uint256 bondAmount = _bondAmount; // Avoid stack too deep error.
+        uint256 vaultSharePrice_ = vaultSharePrice; // Avoid stack too deep error.
+        IHyperdrive.Options calldata options = _options; // Avoid stack too deep error.
         emit CloseLong(
-            _options.destination,
+            options.destination,
             AssetId.encodeAssetId(AssetId.AssetIdPrefix.Long, maturityTime),
             maturityTime,
             baseProceeds,
-            vaultSharePrice,
+            _convertToVaultSharesFromOption(
+                proceeds,
+                vaultSharePrice_,
+                options
+            ),
+            options.asBase,
             bondAmount
         );
 

contracts/src/internal/HyperdriveShort.sol

@@ -117,12 +117,14 @@ abstract contract HyperdriveShort is IHyperdriveEvents, HyperdriveLP {
         _mint(assetId, _options.destination, bondAmount);
 
         // Emit an OpenShort event.
+        IHyperdrive.Options calldata options = _options;
         emit OpenShort(
-            _options.destination,
+            options.destination,
             assetId,
             maturityTime,
             baseDeposit,
-            vaultSharePrice,
+            baseDeposit.divDown(vaultSharePrice),
+            options.asBase,
             bondAmount
         );
 
@@ -223,12 +225,19 @@ abstract contract HyperdriveShort is IHyperdriveEvents, HyperdriveLP {
         // Emit a CloseShort event.
         uint256 bondAmount = _bondAmount; // Avoid stack too deep error.
         uint256 maturityTime = _maturityTime; // Avoid stack too deep error.
+        uint256 vaultSharePrice_ = vaultSharePrice; // Avoid stack too deep error.
+        IHyperdrive.Options calldata options = _options; // Avoid stack too deep error.
         emit CloseShort(
-            _options.destination,
+            options.destination,
             AssetId.encodeAssetId(AssetId.AssetIdPrefix.Short, maturityTime),
             maturityTime,
             baseProceeds,
-            vaultSharePrice,
+            _convertToVaultSharesFromOption(
+                proceeds,
+                vaultSharePrice_,
+                options
+            ),
+            options.asBase,
             bondAmount
         );
 

test/instances/erc4626/ERC4626Validation.t.sol

@@ -287,7 +287,11 @@ abstract contract ERC4626ValidationTest is HyperdriveTest {
             bytes32(uint256(0xfade))
         );
 
-        // Ensure minimumShareReserves were added, and lpTotalSupply increased
+        // Ensure that the decimals are set correctly.
+        assertEq(hyperdrive.decimals(), decimals);
+
+        // Ensure that the minimum share reserves was successfully capitalized
+        // and that the LP total supply was updated to the correct value.
         assertEq(
             hyperdrive.getPoolInfo().lpTotalSupply,
             hyperdrive.getPoolInfo().shareReserves - config.minimumShareReserves

test/instances/steth/StETHHyperdrive.t.sol

@@ -301,6 +301,9 @@ contract StETHHyperdriveTest is HyperdriveTest {
         );
         assertEq(address(bob).balance, bobBalanceBefore - contribution);
 
+        // Ensure that the decimals are set correctly.
+        assertEq(hyperdrive.decimals(), 18);
+
         // Ensure that Bob received the correct amount of LP tokens. He should
         // receive LP shares totaling the amount of shares that he contributed
         // minus the shares set aside for the minimum share reserves and the

test/units/hyperdrive/CloseLongTest.t.sol

@@ -910,12 +910,22 @@ contract CloseLongTest is HyperdriveTest {
             (
                 uint256 eventMaturityTime,
                 uint256 eventBaseAmount,
-                uint256 eventSharePrice,
+                uint256 eventVaultShareAmount,
+                bool eventAsBase,
                 uint256 eventBondAmount
-            ) = abi.decode(log.data, (uint256, uint256, uint256, uint256));
+            ) = abi.decode(
+                    log.data,
+                    (uint256, uint256, uint256, bool, uint256)
+                );
             assertEq(eventMaturityTime, testCase.maturityTime);
             assertEq(eventBaseAmount, testCase.baseProceeds);
-            assertEq(eventSharePrice, hyperdrive.getPoolInfo().vaultSharePrice);
+            assertEq(
+                eventVaultShareAmount,
+                testCase.baseProceeds.divDown(
+                    hyperdrive.getPoolInfo().vaultSharePrice
+                )
+            );
+            assertEq(eventAsBase, true);
             assertEq(eventBondAmount, testCase.bondAmount);
         }