fix: fee-on-transfer token deposit accounting#146
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Use balance-before/balance-after accounting so only the net amount actually received is credited to the depositor. Previous implementation assumed a 1:1 transfer, breaking with fee-on-transfer tokens. - Add _deposit() net-crediting logic - Add MockFeeOnTransferERC20 test mock - Add test_DepositFeeOnTransferTokenCreditsNetAmount test - Closes: #122
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Summary
Closes #122
ERC20 fee-on-transfer tokens break deposit accounting because
_deposit()assumed a 1:1 transfer ratio. Tokens that deduct a fee on every transfer (deflationary tokens) deliver less than the sent amount.This fix uses a balance-before / balance-after pattern to credit only the net amount actually received by the contract.
Changes
_deposit(): measurebalanceOfbefore and aftersafeTransferFrom, credit the deltaMockFeeOnTransferERC20: test mock with configurable fee in basis pointstest_DepositFeeOnTransferTokenCreditsNetAmount: regression test for fee tokensvm.mockCallwith real token transfers in existing deposit/withdraw testsTest plan
forge testpasses (141 tests)