Add comment on 0/0 division of divup

makerdao · Oct 10, 2023 · 7ba968f · 7ba968f
1 parent 4928ce0
commit 7ba968f
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diff --git a/src/AllocatorVault.sol b/src/AllocatorVault.sol
@@ -100,6 +100,7 @@ contract AllocatorVault {
     // --- math ---
 
     function _divup(uint256 x, uint256 y) internal pure returns (uint256 z) {
+        // Note: _divup(0,0) will return 0 differing from natural solidity division
         unchecked {
             z = x != 0 ? ((x - 1) / y) + 1 : 0;
         }

diff --git a/test/AllocatorVault.t.sol b/test/AllocatorVault.t.sol
@@ -28,6 +28,7 @@ contract AllocatorVaultTest is DssTest {
     event Wipe(address indexed sender, uint256 wad);
 
     function _divup(uint256 x, uint256 y) internal pure returns (uint256 z) {
+        // Note: _divup(0,0) will return 0 differing from natural solidity division
         unchecked {
             z = x != 0 ? ((x - 1) / y) + 1 : 0;
         }