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author | furszy <matiasfurszyfer@protonmail.com> | 2022-12-18 10:28:59 -0300 |
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committer | furszy <matiasfurszyfer@protonmail.com> | 2023-04-05 09:32:39 -0300 |
commit | 6107ec2229c5f5b4e944a6b10d38010c850094ac (patch) | |
tree | 2871cf2354d648487253ddab816da55e529dd8ac /src/wallet/test/fuzz/coinselection.cpp | |
parent | 1284223691127e76135a46d251c52416104f0ff1 (diff) | |
download | bitcoin-6107ec2229c5f5b4e944a6b10d38010c850094ac.tar.xz |
coin selection: knapsack, select closest UTXO above target if result exceeds max tx size
The simplest scenario where this is useful is on the 'check_max_weight' unit test
already:
We create 1515 UTXOs with 0.033 BTC each, and 1 UTXO with 50 BTC. Then perform
Coin Selection.
As the selection of the 1515 small UTXOs exceeds the max allowed tx size, the
expectation here is to receive a selection result that only contain the big
UTXO (which is not happening for the reasons stated below).
As knapsack returns a result that exceeds the max allowed transaction size, we
fallback to SRD, which selects coins randomly up until the target is met. So
we end up with a selection result with lot more coins than what is needed.
Diffstat (limited to 'src/wallet/test/fuzz/coinselection.cpp')
-rw-r--r-- | src/wallet/test/fuzz/coinselection.cpp | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/src/wallet/test/fuzz/coinselection.cpp b/src/wallet/test/fuzz/coinselection.cpp index 304190eec1..4878b24c30 100644 --- a/src/wallet/test/fuzz/coinselection.cpp +++ b/src/wallet/test/fuzz/coinselection.cpp @@ -3,6 +3,7 @@ // file COPYING or http://www.opensource.org/licenses/mit-license.php. #include <policy/feerate.h> +#include <policy/policy.h> #include <primitives/transaction.h> #include <test/fuzz/FuzzedDataProvider.h> #include <test/fuzz/fuzz.h> @@ -44,6 +45,9 @@ static void GroupCoins(FuzzedDataProvider& fuzzed_data_provider, const std::vect if (valid_outputgroup) output_groups.push_back(output_group); } +// Returns true if the result contains an error and the message is not empty +static bool HasErrorMsg(const util::Result<SelectionResult>& res) { return !util::ErrorString(res).empty(); } + FUZZ_TARGET(coinselection) { FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()}; @@ -90,12 +94,12 @@ FUZZ_TARGET(coinselection) if (result_srd) result_srd->ComputeAndSetWaste(cost_of_change, cost_of_change, 0); CAmount change_target{GenerateChangeTarget(target, coin_params.m_change_fee, fast_random_context)}; - auto result_knapsack = KnapsackSolver(group_all, target, change_target, fast_random_context); + auto result_knapsack = KnapsackSolver(group_all, target, change_target, fast_random_context, MAX_STANDARD_TX_WEIGHT); if (result_knapsack) result_knapsack->ComputeAndSetWaste(cost_of_change, cost_of_change, 0); // If the total balance is sufficient for the target and we are not using - // effective values, Knapsack should always find a solution. - if (total_balance >= target && subtract_fee_outputs) { + // effective values, Knapsack should always find a solution (unless the selection exceeded the max tx weight). + if (total_balance >= target && subtract_fee_outputs && !HasErrorMsg(result_knapsack)) { assert(result_knapsack); } } |