fix(v3-sdk): refund unspent ETH on native exact-input swaps - #698
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gomesalexandre wants to merge 2 commits into
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fix(v3-sdk): refund unspent ETH on native exact-input swaps#698gomesalexandre wants to merge 2 commits into
gomesalexandre wants to merge 2 commits into
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`SwapRouter.swapCallParameters` only appended a `refundETH` call for exact-output trades. But a native-input exact-input swap sends `msg.value` equal to the exact input amount, and `exactInputSingle` can stop early against `sqrtPriceLimitX96` and consume less than that, so the remainder gets stuck in the router until some later exact-output swap happens to sweep it. Refund whenever the input currency is native, matching the periphery's own "always sweep" pattern. `refundETH` is a no-op when the router holds no ETH, so exact-input swaps without a price limit are unaffected beyond a negligible extra call. closes Uniswap#216
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closes #216
what
SwapRouter.swapCallParameters(v3-sdk) only appends arefundETHsweep for exact-output trades. A native-input exact-input swap can leave ETH stuck in the router.why
For a native-input trade
msg.valueis set to the input amount. For exact-input that is the exactamountIn, andexactInputSingleis encoded withsqrtPriceLimitX96: options.sqrtPriceLimitX96 ?? 0. If a caller sets a price limit and the swap stops early against it, less thanamountInis consumed and the remainder sits in the router until some later exact-output swap happens to sweep it.how
Refund whenever the input currency is native, not only for exact-output:
refundETHis a no-op when the router holds no ETH, so exact-input swaps without a price limit are unaffected beyond a negligible extra call. This matches the periphery's own always-sweep pattern.tests
sqrtPriceLimitX96set now producesmulticall(exactInputSingle, refundETH)(refundETH selector0x12210e8a)--max-warnings 0) and prettier clean. The four native-exact-input tests fail against the previous implementation.