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author | Andrew Chow <achow101-github@achow101.com> | 2022-07-06 10:48:21 -0400 |
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committer | Andrew Chow <achow101-github@achow101.com> | 2022-07-06 11:01:07 -0400 |
commit | aeab1b42e67cc8146bfc7d127d15633bd652fe60 (patch) | |
tree | 37b157e822de87d5213c410c4f158ef71880689c | |
parent | 691a08718beff31d1b821b192609ea3bfdb24d41 (diff) | |
parent | 140d942634f9f1bba191aafa948df57812c0f3fe (diff) | |
download | bitcoin-aeab1b42e67cc8146bfc7d127d15633bd652fe60.tar.xz |
Merge bitcoin/bitcoin#25507: wallet: don't add change fee to target if subtracting fees from output
140d942634f9f1bba191aafa948df57812c0f3fe wallet: don't add change fee to target if subtracting fees from output (S3RK)
Pull request description:
Change fee is payed by the recipient, so we don't need to add it to our target for coin selection.
ACKs for top commit:
achow101:
ACK 140d942634f9f1bba191aafa948df57812c0f3fe
ishaanam:
ACK 140d942634f9f1bba191aafa948df57812c0f3fe
furszy:
Code review ACK 140d9426
Tree-SHA512: b5efd0264c47ecee9204a3fd039bad24c69f9e614c6e1d9bb240ee5be6356b175aa074f3be123e6cfb8becd4d7bd1028eebe18801662cc69d19413d8d5a9dd5c
-rw-r--r-- | src/wallet/spend.cpp | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/wallet/spend.cpp b/src/wallet/spend.cpp index 81055a5a1a..1d22d0993e 100644 --- a/src/wallet/spend.cpp +++ b/src/wallet/spend.cpp @@ -397,10 +397,13 @@ std::optional<SelectionResult> AttemptSelection(const CWallet& wallet, const CAm // The knapsack solver has some legacy behavior where it will spend dust outputs. We retain this behavior, so don't filter for positive only here. std::vector<OutputGroup> all_groups = GroupOutputs(wallet, coins, coin_selection_params, eligibility_filter, false /* positive_only */); + CAmount target_with_change = nTargetValue; // While nTargetValue includes the transaction fees for non-input things, it does not include the fee for creating a change output. - // So we need to include that for KnapsackSolver as well, as we are expecting to create a change output. - if (auto knapsack_result{KnapsackSolver(all_groups, nTargetValue + coin_selection_params.m_change_fee, - coin_selection_params.m_min_change_target, coin_selection_params.rng_fast)}) { + // So we need to include that for KnapsackSolver and SRD as well, as we are expecting to create a change output. + if (!coin_selection_params.m_subtract_fee_outputs) { + target_with_change += coin_selection_params.m_change_fee; + } + if (auto knapsack_result{KnapsackSolver(all_groups, target_with_change, coin_selection_params.m_min_change_target, coin_selection_params.rng_fast)}) { knapsack_result->ComputeAndSetWaste(coin_selection_params.m_cost_of_change); results.push_back(*knapsack_result); } @@ -409,7 +412,7 @@ std::optional<SelectionResult> AttemptSelection(const CWallet& wallet, const CAm // barely meets the target. Just use the lower bound change target instead of the randomly // generated one, since SRD will result in a random change amount anyway; avoid making the // target needlessly large. - const CAmount srd_target = nTargetValue + coin_selection_params.m_change_fee + CHANGE_LOWER; + const CAmount srd_target = target_with_change + CHANGE_LOWER; if (auto srd_result{SelectCoinsSRD(positive_groups, srd_target, coin_selection_params.rng_fast)}) { srd_result->ComputeAndSetWaste(coin_selection_params.m_cost_of_change); results.push_back(*srd_result); |