From a3cf623364e84819bc16fd407b80d8dba46bbcb5 Mon Sep 17 00:00:00 2001 From: Murch Date: Thu, 24 Jul 2025 15:55:43 -0700 Subject: [PATCH] test: Test max_selection_weight edge cases MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Slays Mutant 37 from Bruno’s report: https://gist.github.com/brunoerg/834063398d5002f738506d741513e310 diff --git a/src/wallet/coinselection.cpp b/muts/coinselection.mutant.37.cpp index cee558088f..9747cd26c9 100644 --- a/src/wallet/coinselection.cpp +++ b/muts/coinselection.mutant.37.cpp @@ -128,7 +128,7 @@ util::Result SelectCoinsBnB(std::vector& utxo_pool curr_value > selection_target + cost_of_change || // Selected value is out of range, go back and try other branch (curr_waste > best_waste && is_feerate_high)) { // Don't select things which we know will be more wasteful if the waste is increasing backtrack = true; - } else if (curr_selection_weight > max_selection_weight) { // Selected UTXOs weight exceeds the maximum weight allowed, cannot find more solutions by adding more inputs + } else if (curr_selection_weight >= max_selection_weight) { // Selected UTXOs weight exceeds the maximum weight allowed, cannot find more solutions by adding more inputs max_tx_weight_exceeded = true; // at least one selection attempt exceeded the max weight backtrack = true; } else if (curr_value >= selection_target) { // Selected value is within range --- src/wallet/test/coinselection_tests.cpp | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/src/wallet/test/coinselection_tests.cpp b/src/wallet/test/coinselection_tests.cpp index 99283b719a7..9c390682227 100644 --- a/src/wallet/test/coinselection_tests.cpp +++ b/src/wallet/test/coinselection_tests.cpp @@ -15,6 +15,9 @@ BOOST_FIXTURE_TEST_SUITE(coinselection_tests, TestingSetup) static int next_lock_time = 0; static FastRandomContext default_rand; +static const int P2WPKH_INPUT_VSIZE = 68; +static const int P2WPKH_OUTPUT_VSIZE = 31; + /** Default coin selection parameters (dcsp) allow us to only explicitly set * parameters when a diverging value is relevant in the context of a test. * We use P2WPKH input and output weights for the change weights. */ @@ -22,13 +25,13 @@ static CoinSelectionParams init_default_params() { CoinSelectionParams dcsp{ /*rng_fast*/default_rand, - /*change_output_size=*/31, - /*change_spend_size=*/68, + /*change_output_size=*/P2WPKH_OUTPUT_VSIZE, + /*change_spend_size=*/P2WPKH_INPUT_VSIZE, /*min_change_target=*/50'000, /*effective_feerate=*/CFeeRate(5000), /*long_term_feerate=*/CFeeRate(10'000), /*discard_feerate=*/CFeeRate(3000), - /*tx_noinputs_size=*/11 + 31, //static header size + output size + /*tx_noinputs_size=*/11 + P2WPKH_OUTPUT_VSIZE, //static header size + output size /*avoid_partial=*/false, }; dcsp.m_change_fee = /*155 sats=*/dcsp.m_effective_feerate.GetFee(dcsp.change_output_size); @@ -41,7 +44,7 @@ static CoinSelectionParams init_default_params() static const CoinSelectionParams default_cs_params = init_default_params(); /** Make one OutputGroup with a single UTXO that either has a given effective value (default) or a given amount (`is_eff_value = false`). */ -static OutputGroup MakeCoin(const CAmount& amount, bool is_eff_value = true, CoinSelectionParams cs_params = default_cs_params, int custom_spending_vsize = 68) +static OutputGroup MakeCoin(const CAmount& amount, bool is_eff_value = true, CoinSelectionParams cs_params = default_cs_params, int custom_spending_vsize = P2WPKH_INPUT_VSIZE) { // Always assume that we only have one input CMutableTransaction tx; @@ -93,7 +96,7 @@ static std::string InputAmountsToString(const SelectionResult& selection) return "[" + util::Join(selection.GetInputSet(), " ", [](const auto& input){ return util::ToString(input->txout.nValue);}) + "]"; } -static void TestBnBSuccess(std::string test_title, std::vector& utxo_pool, const CAmount& selection_target, const std::vector& expected_input_amounts, const CoinSelectionParams& cs_params = default_cs_params, int custom_spending_vsize = 68) +static void TestBnBSuccess(std::string test_title, std::vector& utxo_pool, const CAmount& selection_target, const std::vector& expected_input_amounts, const CoinSelectionParams& cs_params = default_cs_params, const int custom_spending_vsize = P2WPKH_INPUT_VSIZE, const int max_selection_weight = MAX_STANDARD_TX_WEIGHT) { SelectionResult expected_result(CAmount(0), SelectionAlgorithm::BNB); CAmount expected_amount = 0; @@ -103,15 +106,15 @@ static void TestBnBSuccess(std::string test_title, std::vector& utx expected_result.AddInput(group); } - const auto result = SelectCoinsBnB(utxo_pool, selection_target, /*cost_of_change=*/default_cs_params.m_cost_of_change, /*max_selection_weight=*/MAX_STANDARD_TX_WEIGHT); + const auto result = SelectCoinsBnB(utxo_pool, selection_target, /*cost_of_change=*/default_cs_params.m_cost_of_change, max_selection_weight); BOOST_CHECK_MESSAGE(result, "Falsy result in BnB-Success: " + test_title); BOOST_CHECK_MESSAGE(HaveEquivalentValues(expected_result, *result), strprintf("Result mismatch in BnB-Success: %s. Expected %s, but got %s", test_title, InputAmountsToString(expected_result), InputAmountsToString(*result))); BOOST_CHECK_MESSAGE(result->GetSelectedValue() == expected_amount, strprintf("Selected amount mismatch in BnB-Success: %s. Expected %d, but got %d", test_title, expected_amount, result->GetSelectedValue())); } -static void TestBnBFail(std::string test_title, std::vector& utxo_pool, const CAmount& selection_target, const bool expect_max_weight_exceeded = false) +static void TestBnBFail(std::string test_title, std::vector& utxo_pool, const CAmount& selection_target, int max_selection_weight = MAX_STANDARD_TX_WEIGHT, const bool expect_max_weight_exceeded = false) { - const auto result = SelectCoinsBnB(utxo_pool, selection_target, /*cost_of_change=*/default_cs_params.m_cost_of_change, /*max_selection_weight=*/MAX_STANDARD_TX_WEIGHT); + const auto result = SelectCoinsBnB(utxo_pool, selection_target, /*cost_of_change=*/default_cs_params.m_cost_of_change, max_selection_weight); BOOST_CHECK_MESSAGE(!result, "BnB-Fail: " + test_title); bool max_weight_exceeded = util::ErrorString(result).original.find("The inputs size exceeds the maximum weight") != std::string::npos; BOOST_CHECK(expect_max_weight_exceeded == max_weight_exceeded); @@ -145,6 +148,10 @@ BOOST_AUTO_TEST_CASE(bnb_test) // BnB fails to find changeless solution when overshooting by cost_of_change + 1 sat TestBnBFail("Overshoot upper bound", utxo_pool, /*selection_target=*/4 * CENT - default_cs_params.m_cost_of_change - 1); + TestBnBSuccess("Select max weight", utxo_pool, /*selection_target=*/4 * CENT, /*expected_input_amounts=*/{1 * CENT, 3 * CENT}, cs_params, /*custom_spending_vsize=*/P2WPKH_INPUT_VSIZE, /*max_selection_weight=*/4 * 2 * P2WPKH_INPUT_VSIZE); + + TestBnBFail("Exceed max weight", utxo_pool, /*selection_target=*/4 * CENT, /*max_selection_weight=*/4 * 2 * P2WPKH_INPUT_VSIZE - 1, /*expect_max_weight_exceeded=*/true); + // Simple cases without BnB solution TestBnBFail("Smallest combination too big", utxo_pool, /*selection_target=*/0.5 * CENT); TestBnBFail("No UTXO combination in target window", utxo_pool, /*selection_target=*/7 * CENT);