feat: function to calculate min fee in wei for a given stream ID

bun.lock

@@ -6,7 +6,7 @@
       "dependencies": {
         "@openzeppelin/contracts": "5.3.0",
         "@prb/math": "4.1.0",
-        "@sablier/evm-utils": "github:sablier-labs/evm-utils",
+        "@sablier/evm-utils": "github:sablier-labs/evm-utils#31f94ff",
       },
       "devDependencies": {
         "@sablier/devkit": "github:sablier-labs/devkit",
@@ -172,7 +172,7 @@
 
     "@sablier/devkit": ["@sablier/devkit@github:sablier-labs/devkit#16816ca", {}, "sablier-labs-devkit-16816ca"],
 
-    "@sablier/evm-utils": ["@sablier/evm-utils@github:sablier-labs/evm-utils#cc3a85c", { "dependencies": { "@chainlink/contracts": "1.3.0" } }, "sablier-labs-evm-utils-cc3a85c"],
+    "@sablier/evm-utils": ["@sablier/evm-utils@github:sablier-labs/evm-utils#31f94ff", { "dependencies": { "@chainlink/contracts": "1.3.0" } }, "sablier-labs-evm-utils-31f94ff"],
 
     "@scroll-tech/contracts": ["@scroll-tech/[email protected]", "", {}, "sha512-aBbDOc3WB/WveZdpJYcrfvMYMz7ZTEiW8M9XMJLba8p9FAR5KGYB/cV+8+EUsq3MKt7C1BfR+WnXoTVdvwIY6w=="],
 

package.json

@@ -13,7 +13,7 @@
   "dependencies": {
     "@openzeppelin/contracts": "5.3.0",
     "@prb/math": "4.1.0",
-    "@sablier/evm-utils": "github:sablier-labs/evm-utils"
+    "@sablier/evm-utils": "github:sablier-labs/evm-utils#31f94ff"
   },
   "devDependencies": {
     "@sablier/devkit": "github:sablier-labs/devkit",

src/SablierLockup.sol

@@ -9,6 +9,7 @@ import { IERC721Metadata } from "@openzeppelin/contracts/token/ERC721/extensions
 import { IERC165 } from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
 import { Batch } from "@sablier/evm-utils/src/Batch.sol";
 import { Comptrollerable } from "@sablier/evm-utils/src/Comptrollerable.sol";
+import { ISablierComptroller } from "@sablier/evm-utils/src/interfaces/ISablierComptroller.sol";
 
 import { SablierLockupDynamic } from "./abstracts/SablierLockupDynamic.sol";
 import { SablierLockupLinear } from "./abstracts/SablierLockupLinear.sol";
@@ -64,6 +65,21 @@ contract SablierLockup is
                           USER-FACING READ-ONLY FUNCTIONS
     //////////////////////////////////////////////////////////////////////////*/
 
+    /// @inheritdoc ISablierLockup
+    function calculateMinFeeWei(uint256 streamId)
+        external
+        view
+        override
+        notNull(streamId)
+        returns (uint256 minFeeWei)
+    {
+        // Calculate the minimum fee in wei for the stream sender.
+        minFeeWei = comptroller.calculateMinFeeWeiFor({
+            protocol: ISablierComptroller.Protocol.Lockup,
+            user: _streams[streamId].sender
+        });
+    }
+
     /// @inheritdoc ISablierLockup
     function getRecipient(uint256 streamId) external view override returns (address recipient) {
         // Check the stream NFT exists and return the owner, which is the stream's recipient.
@@ -645,7 +661,12 @@ contract SablierLockup is
 
     /// @dev See the documentation for the user-facing functions that call this private function.
     function _withdraw(uint256 streamId, address to, uint128 amount) private {
-        uint256 minFeeWei = comptroller.calculateLockupMinFeeWeiFor(_streams[streamId].sender);
+        // Calculate the minimum fee in wei for the stream sender.
+        uint256 minFeeWei = comptroller.calculateMinFeeWeiFor({
+            protocol: ISablierComptroller.Protocol.Lockup,
+            user: _streams[streamId].sender
+        });
+
         uint256 feePaid = msg.value;
 
         // Check: fee paid is at least the minimum fee.

src/interfaces/ISablierLockup.sol

@@ -87,6 +87,11 @@ interface ISablierLockup is
                           USER-FACING READ-ONLY FUNCTIONS
     //////////////////////////////////////////////////////////////////////////*/
 
+    /// @notice Calculates the minimum fee in wei required to withdraw from the given stream ID.
+    /// @dev Reverts if `streamId` references a null stream.
+    /// @param streamId The stream ID for the query.
+    function calculateMinFeeWei(uint256 streamId) external view returns (uint256 minFeeWei);
+
     /// @notice Retrieves the stream's recipient.
     /// @dev Reverts if the NFT has been burned.
     /// @param streamId The stream ID for the query.

tests/integration/concrete/lockup/calculate-min-fee-wei-for/calculateMinFeeWeiFor.t.sol

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity >=0.8.22 <0.9.0;
+
+import { ISablierComptroller } from "@sablier/evm-utils/src/interfaces/ISablierComptroller.sol";
+
+import { Integration_Test } from "../../../Integration.t.sol";
+
+contract CalculateMinFeeWeiFor_Integration_Concrete_Test is Integration_Test {
+    function test_RevertGiven_Null() external {
+        expectRevert_Null({ callData: abi.encodeCall(lockup.calculateMinFeeWei, ids.nullStream) });
+    }
+
+    function test_GivenCustomFeeSet() external givenNotNull {
+        setMsgSender(admin);
+
+        uint256 customFeeUSD = 100e8; // 100 USD.
+
+        // Set the custom fee.
+        comptroller.setCustomFeeUSDFor({
+            protocol: ISablierComptroller.Protocol.Lockup,
+            user: users.sender,
+            customFeeUSD: customFeeUSD
+        });
+
+        uint256 expectedFeeWei = (1e18 * customFeeUSD) / ETH_PRICE_USD;
+
+        // It should return the custom fee in wei.
+        assertEq(lockup.calculateMinFeeWei(ids.defaultStream), expectedFeeWei, "customFeeWei");
+    }
+
+    function test_GivenCustomFeeNotSet() external view givenNotNull {
+        // It should return the minimum fee in wei.
+        assertEq(lockup.calculateMinFeeWei(ids.defaultStream), LOCKUP_MIN_FEE_WEI, "minFeeWei");
+    }
+}

tests/integration/concrete/lockup/calculate-min-fee-wei-for/calculateMinFeeWeiFor.tree

@@ -0,0 +1,8 @@
+CalculateMinFeeWeiFor_Integration_Concrete_Test
+├── given null
+│  └── it should revert
+└── given not null
+   ├── given custom fee set
+   │  └── it should return the custom fee in wei
+   └── given custom fee not set
+      └── it should return the minimum fee in wei