Bitcoin Core  27.99.0
P2P Digital Currency
coinselector_tests.cpp
Go to the documentation of this file.
1 // Copyright (c) 2017-2022 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 #include <consensus/amount.h>
6 #include <node/context.h>
7 #include <policy/policy.h>
9 #include <random.h>
10 #include <test/util/setup_common.h>
11 #include <util/translation.h>
12 #include <wallet/coincontrol.h>
13 #include <wallet/coinselection.h>
14 #include <wallet/spend.h>
15 #include <wallet/test/util.h>
17 #include <wallet/wallet.h>
18 
19 #include <algorithm>
20 #include <boost/test/unit_test.hpp>
21 #include <random>
22 
23 namespace wallet {
24 BOOST_FIXTURE_TEST_SUITE(coinselector_tests, WalletTestingSetup)
25 
26 // how many times to run all the tests to have a chance to catch errors that only show up with particular random shuffles
27 #define RUN_TESTS 100
28 
29 // some tests fail 1% of the time due to bad luck.
30 // we repeat those tests this many times and only complain if all iterations of the test fail
31 #define RANDOM_REPEATS 5
32 
33 typedef std::set<std::shared_ptr<COutput>> CoinSet;
34 
35 static const CoinEligibilityFilter filter_standard(1, 6, 0);
38 static int nextLockTime = 0;
39 
40 static void add_coin(const CAmount& nValue, int nInput, std::vector<COutput>& set)
41 {
43  tx.vout.resize(nInput + 1);
44  tx.vout[nInput].nValue = nValue;
45  tx.nLockTime = nextLockTime++; // so all transactions get different hashes
46  set.emplace_back(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, /*input_bytes=*/ -1, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, /*fees=*/ 0);
47 }
48 
49 static void add_coin(const CAmount& nValue, int nInput, SelectionResult& result)
50 {
52  tx.vout.resize(nInput + 1);
53  tx.vout[nInput].nValue = nValue;
54  tx.nLockTime = nextLockTime++; // so all transactions get different hashes
55  COutput output(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, /*input_bytes=*/ -1, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, /*fees=*/ 0);
57  group.Insert(std::make_shared<COutput>(output), /*ancestors=*/ 0, /*descendants=*/ 0);
58  result.AddInput(group);
59 }
60 
61 static void add_coin(const CAmount& nValue, int nInput, SelectionResult& result, CAmount fee, CAmount long_term_fee)
62 {
64  tx.vout.resize(nInput + 1);
65  tx.vout[nInput].nValue = nValue;
66  tx.nLockTime = nextLockTime++; // so all transactions get different hashes
67  std::shared_ptr<COutput> coin = std::make_shared<COutput>(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, /*input_bytes=*/ 148, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, fee);
69  group.Insert(coin, /*ancestors=*/ 0, /*descendants=*/ 0);
70  coin->long_term_fee = long_term_fee; // group.Insert() will modify long_term_fee, so we need to set it afterwards
71  result.AddInput(group);
72 }
73 
74 static void add_coin(CoinsResult& available_coins, CWallet& wallet, const CAmount& nValue, CFeeRate feerate = CFeeRate(0), int nAge = 6*24, bool fIsFromMe = false, int nInput =0, bool spendable = false, int custom_size = 0)
75 {
77  tx.nLockTime = nextLockTime++; // so all transactions get different hashes
78  tx.vout.resize(nInput + 1);
79  tx.vout[nInput].nValue = nValue;
80  if (spendable) {
81  tx.vout[nInput].scriptPubKey = GetScriptForDestination(*Assert(wallet.GetNewDestination(OutputType::BECH32, "")));
82  }
83  uint256 txid = tx.GetHash();
84 
85  LOCK(wallet.cs_wallet);
86  auto ret = wallet.mapWallet.emplace(std::piecewise_construct, std::forward_as_tuple(txid), std::forward_as_tuple(MakeTransactionRef(std::move(tx)), TxStateInactive{}));
87  assert(ret.second);
88  CWalletTx& wtx = (*ret.first).second;
89  const auto& txout = wtx.tx->vout.at(nInput);
90  available_coins.Add(OutputType::BECH32, {COutPoint(wtx.GetHash(), nInput), txout, nAge, custom_size == 0 ? CalculateMaximumSignedInputSize(txout, &wallet, /*coin_control=*/nullptr) : custom_size, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, wtx.GetTxTime(), fIsFromMe, feerate});
91 }
92 
93 // Helpers
94 std::optional<SelectionResult> KnapsackSolver(std::vector<OutputGroup>& groups, const CAmount& nTargetValue,
95  CAmount change_target, FastRandomContext& rng)
96 {
97  auto res{KnapsackSolver(groups, nTargetValue, change_target, rng, MAX_STANDARD_TX_WEIGHT)};
98  return res ? std::optional<SelectionResult>(*res) : std::nullopt;
99 }
100 
101 std::optional<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_pool, const CAmount& selection_target, const CAmount& cost_of_change)
102 {
103  auto res{SelectCoinsBnB(utxo_pool, selection_target, cost_of_change, MAX_STANDARD_TX_WEIGHT)};
104  return res ? std::optional<SelectionResult>(*res) : std::nullopt;
105 }
106 
109 static bool EquivalentResult(const SelectionResult& a, const SelectionResult& b)
110 {
111  std::vector<CAmount> a_amts;
112  std::vector<CAmount> b_amts;
113  for (const auto& coin : a.GetInputSet()) {
114  a_amts.push_back(coin->txout.nValue);
115  }
116  for (const auto& coin : b.GetInputSet()) {
117  b_amts.push_back(coin->txout.nValue);
118  }
119  std::sort(a_amts.begin(), a_amts.end());
120  std::sort(b_amts.begin(), b_amts.end());
121 
122  std::pair<std::vector<CAmount>::iterator, std::vector<CAmount>::iterator> ret = std::mismatch(a_amts.begin(), a_amts.end(), b_amts.begin());
123  return ret.first == a_amts.end() && ret.second == b_amts.end();
124 }
125 
127 static bool EqualResult(const SelectionResult& a, const SelectionResult& b)
128 {
129  std::pair<CoinSet::iterator, CoinSet::iterator> ret = std::mismatch(a.GetInputSet().begin(), a.GetInputSet().end(), b.GetInputSet().begin(),
130  [](const std::shared_ptr<COutput>& a, const std::shared_ptr<COutput>& b) {
131  return a->outpoint == b->outpoint;
132  });
133  return ret.first == a.GetInputSet().end() && ret.second == b.GetInputSet().end();
134 }
135 
136 static CAmount make_hard_case(int utxos, std::vector<COutput>& utxo_pool)
137 {
138  utxo_pool.clear();
139  CAmount target = 0;
140  for (int i = 0; i < utxos; ++i) {
141  target += CAmount{1} << (utxos+i);
142  add_coin(CAmount{1} << (utxos+i), 2*i, utxo_pool);
143  add_coin((CAmount{1} << (utxos+i)) + (CAmount{1} << (utxos-1-i)), 2*i + 1, utxo_pool);
144  }
145  return target;
146 }
147 
148 inline std::vector<OutputGroup>& GroupCoins(const std::vector<COutput>& available_coins, bool subtract_fee_outputs = false)
149 {
150  static std::vector<OutputGroup> static_groups;
151  static_groups.clear();
152  for (auto& coin : available_coins) {
153  static_groups.emplace_back();
154  OutputGroup& group = static_groups.back();
155  group.Insert(std::make_shared<COutput>(coin), /*ancestors=*/ 0, /*descendants=*/ 0);
156  group.m_subtract_fee_outputs = subtract_fee_outputs;
157  }
158  return static_groups;
159 }
160 
161 inline std::vector<OutputGroup>& KnapsackGroupOutputs(const CoinsResult& available_coins, CWallet& wallet, const CoinEligibilityFilter& filter)
162 {
163  FastRandomContext rand{};
164  CoinSelectionParams coin_selection_params{
165  rand,
166  /*change_output_size=*/ 0,
167  /*change_spend_size=*/ 0,
168  /*min_change_target=*/ CENT,
169  /*effective_feerate=*/ CFeeRate(0),
170  /*long_term_feerate=*/ CFeeRate(0),
171  /*discard_feerate=*/ CFeeRate(0),
172  /*tx_noinputs_size=*/ 0,
173  /*avoid_partial=*/ false,
174  };
175  static OutputGroupTypeMap static_groups;
176  static_groups = GroupOutputs(wallet, available_coins, coin_selection_params, {{filter}})[filter];
177  return static_groups.all_groups.mixed_group;
178 }
179 
180 static std::unique_ptr<CWallet> NewWallet(const node::NodeContext& m_node, const std::string& wallet_name = "")
181 {
182  std::unique_ptr<CWallet> wallet = std::make_unique<CWallet>(m_node.chain.get(), wallet_name, CreateMockableWalletDatabase());
183  BOOST_CHECK(wallet->LoadWallet() == DBErrors::LOAD_OK);
184  LOCK(wallet->cs_wallet);
185  wallet->SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
186  wallet->SetupDescriptorScriptPubKeyMans();
187  return wallet;
188 }
189 
190 // Branch and bound coin selection tests
191 BOOST_AUTO_TEST_CASE(bnb_search_test)
192 {
193  FastRandomContext rand{};
194  // Setup
195  std::vector<COutput> utxo_pool;
196  SelectionResult expected_result(CAmount(0), SelectionAlgorithm::BNB);
197 
199  // Known Outcome tests //
201 
202  // Empty utxo pool
203  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(utxo_pool), 1 * CENT, 0.5 * CENT));
204 
205  // Add utxos
206  add_coin(1 * CENT, 1, utxo_pool);
207  add_coin(2 * CENT, 2, utxo_pool);
208  add_coin(3 * CENT, 3, utxo_pool);
209  add_coin(4 * CENT, 4, utxo_pool);
210 
211  // Select 1 Cent
212  add_coin(1 * CENT, 1, expected_result);
213  const auto result1 = SelectCoinsBnB(GroupCoins(utxo_pool), 1 * CENT, 0.5 * CENT);
214  BOOST_CHECK(result1);
215  BOOST_CHECK(EquivalentResult(expected_result, *result1));
216  BOOST_CHECK_EQUAL(result1->GetSelectedValue(), 1 * CENT);
217  expected_result.Clear();
218 
219  // Select 2 Cent
220  add_coin(2 * CENT, 2, expected_result);
221  const auto result2 = SelectCoinsBnB(GroupCoins(utxo_pool), 2 * CENT, 0.5 * CENT);
222  BOOST_CHECK(result2);
223  BOOST_CHECK(EquivalentResult(expected_result, *result2));
224  BOOST_CHECK_EQUAL(result2->GetSelectedValue(), 2 * CENT);
225  expected_result.Clear();
226 
227  // Select 5 Cent
228  add_coin(3 * CENT, 3, expected_result);
229  add_coin(2 * CENT, 2, expected_result);
230  const auto result3 = SelectCoinsBnB(GroupCoins(utxo_pool), 5 * CENT, 0.5 * CENT);
231  BOOST_CHECK(result3);
232  BOOST_CHECK(EquivalentResult(expected_result, *result3));
233  BOOST_CHECK_EQUAL(result3->GetSelectedValue(), 5 * CENT);
234  expected_result.Clear();
235 
236  // Select 11 Cent, not possible
237  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(utxo_pool), 11 * CENT, 0.5 * CENT));
238  expected_result.Clear();
239 
240  // Cost of change is greater than the difference between target value and utxo sum
241  add_coin(1 * CENT, 1, expected_result);
242  const auto result4 = SelectCoinsBnB(GroupCoins(utxo_pool), 0.9 * CENT, 0.5 * CENT);
243  BOOST_CHECK(result4);
244  BOOST_CHECK_EQUAL(result4->GetSelectedValue(), 1 * CENT);
245  BOOST_CHECK(EquivalentResult(expected_result, *result4));
246  expected_result.Clear();
247 
248  // Cost of change is less than the difference between target value and utxo sum
249  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(utxo_pool), 0.9 * CENT, 0));
250  expected_result.Clear();
251 
252  // Select 10 Cent
253  add_coin(5 * CENT, 5, utxo_pool);
254  add_coin(4 * CENT, 4, expected_result);
255  add_coin(3 * CENT, 3, expected_result);
256  add_coin(2 * CENT, 2, expected_result);
257  add_coin(1 * CENT, 1, expected_result);
258  const auto result5 = SelectCoinsBnB(GroupCoins(utxo_pool), 10 * CENT, 0.5 * CENT);
259  BOOST_CHECK(result5);
260  BOOST_CHECK(EquivalentResult(expected_result, *result5));
261  BOOST_CHECK_EQUAL(result5->GetSelectedValue(), 10 * CENT);
262  expected_result.Clear();
263 
264  // Select 0.25 Cent, not possible
265  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(utxo_pool), 0.25 * CENT, 0.5 * CENT));
266  expected_result.Clear();
267 
268  // Iteration exhaustion test
269  CAmount target = make_hard_case(17, utxo_pool);
270  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(utxo_pool), target, 1)); // Should exhaust
271  target = make_hard_case(14, utxo_pool);
272  const auto result7 = SelectCoinsBnB(GroupCoins(utxo_pool), target, 1); // Should not exhaust
273  BOOST_CHECK(result7);
274 
275  // Test same value early bailout optimization
276  utxo_pool.clear();
277  add_coin(7 * CENT, 7, expected_result);
278  add_coin(7 * CENT, 7, expected_result);
279  add_coin(7 * CENT, 7, expected_result);
280  add_coin(7 * CENT, 7, expected_result);
281  add_coin(2 * CENT, 7, expected_result);
282  add_coin(7 * CENT, 7, utxo_pool);
283  add_coin(7 * CENT, 7, utxo_pool);
284  add_coin(7 * CENT, 7, utxo_pool);
285  add_coin(7 * CENT, 7, utxo_pool);
286  add_coin(2 * CENT, 7, utxo_pool);
287  for (int i = 0; i < 50000; ++i) {
288  add_coin(5 * CENT, 7, utxo_pool);
289  }
290  const auto result8 = SelectCoinsBnB(GroupCoins(utxo_pool), 30 * CENT, 5000);
291  BOOST_CHECK(result8);
292  BOOST_CHECK_EQUAL(result8->GetSelectedValue(), 30 * CENT);
293  BOOST_CHECK(EquivalentResult(expected_result, *result8));
294 
296  // Behavior tests //
298  // Select 1 Cent with pool of only greater than 5 Cent
299  utxo_pool.clear();
300  for (int i = 5; i <= 20; ++i) {
301  add_coin(i * CENT, i, utxo_pool);
302  }
303  // Run 100 times, to make sure it is never finding a solution
304  for (int i = 0; i < 100; ++i) {
305  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(utxo_pool), 1 * CENT, 2 * CENT));
306  }
307 
308  // Make sure that effective value is working in AttemptSelection when BnB is used
309  CoinSelectionParams coin_selection_params_bnb{
310  rand,
311  /*change_output_size=*/ 31,
312  /*change_spend_size=*/ 68,
313  /*min_change_target=*/ 0,
314  /*effective_feerate=*/ CFeeRate(3000),
315  /*long_term_feerate=*/ CFeeRate(1000),
316  /*discard_feerate=*/ CFeeRate(1000),
317  /*tx_noinputs_size=*/ 0,
318  /*avoid_partial=*/ false,
319  };
320  coin_selection_params_bnb.m_change_fee = coin_selection_params_bnb.m_effective_feerate.GetFee(coin_selection_params_bnb.change_output_size);
321  coin_selection_params_bnb.m_cost_of_change = coin_selection_params_bnb.m_effective_feerate.GetFee(coin_selection_params_bnb.change_spend_size) + coin_selection_params_bnb.m_change_fee;
322  coin_selection_params_bnb.min_viable_change = coin_selection_params_bnb.m_effective_feerate.GetFee(coin_selection_params_bnb.change_spend_size);
323 
324  {
325  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
326 
327  CoinsResult available_coins;
328 
329  add_coin(available_coins, *wallet, 1, coin_selection_params_bnb.m_effective_feerate);
330  available_coins.All().at(0).input_bytes = 40; // Make sure that it has a negative effective value. The next check should assert if this somehow got through. Otherwise it will fail
331  BOOST_CHECK(!SelectCoinsBnB(GroupCoins(available_coins.All()), 1 * CENT, coin_selection_params_bnb.m_cost_of_change));
332 
333  // Test fees subtracted from output:
334  available_coins.Clear();
335  add_coin(available_coins, *wallet, 1 * CENT, coin_selection_params_bnb.m_effective_feerate);
336  available_coins.All().at(0).input_bytes = 40;
337  const auto result9 = SelectCoinsBnB(GroupCoins(available_coins.All()), 1 * CENT, coin_selection_params_bnb.m_cost_of_change);
338  BOOST_CHECK(result9);
339  BOOST_CHECK_EQUAL(result9->GetSelectedValue(), 1 * CENT);
340  }
341 
342  {
343  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
344 
345  CoinsResult available_coins;
346 
347  coin_selection_params_bnb.m_effective_feerate = CFeeRate(0);
348  add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
349  add_coin(available_coins, *wallet, 3 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
350  add_coin(available_coins, *wallet, 2 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
351  CCoinControl coin_control;
352  coin_control.m_allow_other_inputs = true;
353  COutput select_coin = available_coins.All().at(0);
354  coin_control.Select(select_coin.outpoint);
355  PreSelectedInputs selected_input;
356  selected_input.Insert(select_coin, coin_selection_params_bnb.m_subtract_fee_outputs);
357  available_coins.Erase({available_coins.coins[OutputType::BECH32].begin()->outpoint});
358 
359  LOCK(wallet->cs_wallet);
360  const auto result10 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
361  BOOST_CHECK(result10);
362  }
363  {
364  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
365  LOCK(wallet->cs_wallet); // Every 'SelectCoins' call requires it
366 
367  CoinsResult available_coins;
368 
369  // single coin should be selected when effective fee > long term fee
370  coin_selection_params_bnb.m_effective_feerate = CFeeRate(5000);
371  coin_selection_params_bnb.m_long_term_feerate = CFeeRate(3000);
372 
373  // Add selectable outputs, increasing their raw amounts by their input fee to make the effective value equal to the raw amount
374  CAmount input_fee = coin_selection_params_bnb.m_effective_feerate.GetFee(/*num_bytes=*/68); // bech32 input size (default test output type)
375  add_coin(available_coins, *wallet, 10 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
376  add_coin(available_coins, *wallet, 9 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
377  add_coin(available_coins, *wallet, 1 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
378 
379  expected_result.Clear();
380  add_coin(10 * CENT + input_fee, 2, expected_result);
381  CCoinControl coin_control;
382  const auto result11 = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, 10 * CENT, coin_control, coin_selection_params_bnb);
383  BOOST_CHECK(EquivalentResult(expected_result, *result11));
384  available_coins.Clear();
385 
386  // more coins should be selected when effective fee < long term fee
387  coin_selection_params_bnb.m_effective_feerate = CFeeRate(3000);
388  coin_selection_params_bnb.m_long_term_feerate = CFeeRate(5000);
389 
390  // Add selectable outputs, increasing their raw amounts by their input fee to make the effective value equal to the raw amount
391  input_fee = coin_selection_params_bnb.m_effective_feerate.GetFee(/*num_bytes=*/68); // bech32 input size (default test output type)
392  add_coin(available_coins, *wallet, 10 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
393  add_coin(available_coins, *wallet, 9 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
394  add_coin(available_coins, *wallet, 1 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
395 
396  expected_result.Clear();
397  add_coin(9 * CENT + input_fee, 2, expected_result);
398  add_coin(1 * CENT + input_fee, 2, expected_result);
399  const auto result12 = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, 10 * CENT, coin_control, coin_selection_params_bnb);
400  BOOST_CHECK(EquivalentResult(expected_result, *result12));
401  available_coins.Clear();
402 
403  // pre selected coin should be selected even if disadvantageous
404  coin_selection_params_bnb.m_effective_feerate = CFeeRate(5000);
405  coin_selection_params_bnb.m_long_term_feerate = CFeeRate(3000);
406 
407  // Add selectable outputs, increasing their raw amounts by their input fee to make the effective value equal to the raw amount
408  input_fee = coin_selection_params_bnb.m_effective_feerate.GetFee(/*num_bytes=*/68); // bech32 input size (default test output type)
409  add_coin(available_coins, *wallet, 10 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
410  add_coin(available_coins, *wallet, 9 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
411  add_coin(available_coins, *wallet, 1 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
412 
413  expected_result.Clear();
414  add_coin(9 * CENT + input_fee, 2, expected_result);
415  add_coin(1 * CENT + input_fee, 2, expected_result);
416  coin_control.m_allow_other_inputs = true;
417  COutput select_coin = available_coins.All().at(1); // pre select 9 coin
418  coin_control.Select(select_coin.outpoint);
419  PreSelectedInputs selected_input;
420  selected_input.Insert(select_coin, coin_selection_params_bnb.m_subtract_fee_outputs);
421  available_coins.Erase({(++available_coins.coins[OutputType::BECH32].begin())->outpoint});
422  const auto result13 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
423  BOOST_CHECK(EquivalentResult(expected_result, *result13));
424  }
425 
426  {
427  // Test bnb max weight exceeded
428  // Inputs set [10, 9, 8, 5, 3, 1], Selection Target = 16 and coin 5 exceeding the max weight.
429 
430  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
431 
432  CoinsResult available_coins;
433  add_coin(available_coins, *wallet, 10 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
434  add_coin(available_coins, *wallet, 9 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
435  add_coin(available_coins, *wallet, 8 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
436  add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true, /*custom_size=*/MAX_STANDARD_TX_WEIGHT);
437  add_coin(available_coins, *wallet, 3 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
438  add_coin(available_coins, *wallet, 1 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
439 
440  CAmount selection_target = 16 * CENT;
441  const auto& no_res = SelectCoinsBnB(GroupCoins(available_coins.All(), /*subtract_fee_outputs*/true),
442  selection_target, /*cost_of_change=*/0, MAX_STANDARD_TX_WEIGHT);
443  BOOST_REQUIRE(!no_res);
444  BOOST_CHECK(util::ErrorString(no_res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
445 
446  // Now add same coin value with a good size and check that it gets selected
447  add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
448  const auto& res = SelectCoinsBnB(GroupCoins(available_coins.All(), /*subtract_fee_outputs*/true), selection_target, /*cost_of_change=*/0);
449 
450  expected_result.Clear();
451  add_coin(8 * CENT, 2, expected_result);
452  add_coin(5 * CENT, 2, expected_result);
453  add_coin(3 * CENT, 2, expected_result);
454  BOOST_CHECK(EquivalentResult(expected_result, *res));
455  }
456 }
457 
458 BOOST_AUTO_TEST_CASE(bnb_sffo_restriction)
459 {
460  // Verify the coin selection process does not produce a BnB solution when SFFO is enabled.
461  // This is currently problematic because it could require a change output. And BnB is specialized on changeless solutions.
462  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
463  WITH_LOCK(wallet->cs_wallet, wallet->SetLastBlockProcessed(300, uint256{})); // set a high block so internal UTXOs are selectable
464 
465  FastRandomContext rand{};
466  CoinSelectionParams params{
467  rand,
468  /*change_output_size=*/ 31, // unused value, p2wpkh output size (wallet default change type)
469  /*change_spend_size=*/ 68, // unused value, p2wpkh input size (high-r signature)
470  /*min_change_target=*/ 0, // dummy, set later
471  /*effective_feerate=*/ CFeeRate(3000),
472  /*long_term_feerate=*/ CFeeRate(1000),
473  /*discard_feerate=*/ CFeeRate(1000),
474  /*tx_noinputs_size=*/ 0,
475  /*avoid_partial=*/ false,
476  };
477  params.m_subtract_fee_outputs = true;
478  params.m_change_fee = params.m_effective_feerate.GetFee(params.change_output_size);
479  params.m_cost_of_change = params.m_discard_feerate.GetFee(params.change_spend_size) + params.m_change_fee;
480  params.m_min_change_target = params.m_cost_of_change + 1;
481  // Add spendable coin at the BnB selection upper bound
482  CoinsResult available_coins;
483  add_coin(available_coins, *wallet, COIN + params.m_cost_of_change, /*feerate=*/params.m_effective_feerate, /*nAge=*/6, /*fIsFromMe=*/true, /*nInput=*/0, /*spendable=*/true);
484  add_coin(available_coins, *wallet, 0.5 * COIN + params.m_cost_of_change, /*feerate=*/params.m_effective_feerate, /*nAge=*/6, /*fIsFromMe=*/true, /*nInput=*/0, /*spendable=*/true);
485  add_coin(available_coins, *wallet, 0.5 * COIN, /*feerate=*/params.m_effective_feerate, /*nAge=*/6, /*fIsFromMe=*/true, /*nInput=*/0, /*spendable=*/true);
486  // Knapsack will only find a changeless solution on an exact match to the satoshi, SRD doesn’t look for changeless
487  // If BnB were run, it would produce a single input solution with the best waste score
488  auto result = WITH_LOCK(wallet->cs_wallet, return SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, COIN, /*coin_control=*/{}, params));
489  BOOST_CHECK(result.has_value());
490  BOOST_CHECK_NE(result->GetAlgo(), SelectionAlgorithm::BNB);
491  BOOST_CHECK(result->GetInputSet().size() == 2);
492  // We have only considered BnB, SRD, and Knapsack. Test needs to be reevaluated if new algo is added
493  BOOST_CHECK(result->GetAlgo() == SelectionAlgorithm::SRD || result->GetAlgo() == SelectionAlgorithm::KNAPSACK);
494 }
495 
496 BOOST_AUTO_TEST_CASE(knapsack_solver_test)
497 {
498  FastRandomContext rand{};
499  const auto temp1{[&rand](std::vector<OutputGroup>& g, const CAmount& v, CAmount c) { return KnapsackSolver(g, v, c, rand); }};
500  const auto KnapsackSolver{temp1};
501  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
502 
503  CoinsResult available_coins;
504 
505  // test multiple times to allow for differences in the shuffle order
506  for (int i = 0; i < RUN_TESTS; i++)
507  {
508  available_coins.Clear();
509 
510  // with an empty wallet we can't even pay one cent
512 
513  add_coin(available_coins, *wallet, 1*CENT, CFeeRate(0), 4); // add a new 1 cent coin
514 
515  // with a new 1 cent coin, we still can't find a mature 1 cent
517 
518  // but we can find a new 1 cent
519  const auto result1 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
520  BOOST_CHECK(result1);
521  BOOST_CHECK_EQUAL(result1->GetSelectedValue(), 1 * CENT);
522 
523  add_coin(available_coins, *wallet, 2*CENT); // add a mature 2 cent coin
524 
525  // we can't make 3 cents of mature coins
527 
528  // we can make 3 cents of new coins
529  const auto result2 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 3 * CENT, CENT);
530  BOOST_CHECK(result2);
531  BOOST_CHECK_EQUAL(result2->GetSelectedValue(), 3 * CENT);
532 
533  add_coin(available_coins, *wallet, 5*CENT); // add a mature 5 cent coin,
534  add_coin(available_coins, *wallet, 10*CENT, CFeeRate(0), 3, true); // a new 10 cent coin sent from one of our own addresses
535  add_coin(available_coins, *wallet, 20*CENT); // and a mature 20 cent coin
536 
537  // now we have new: 1+10=11 (of which 10 was self-sent), and mature: 2+5+20=27. total = 38
538 
539  // we can't make 38 cents only if we disallow new coins:
541  // we can't even make 37 cents if we don't allow new coins even if they're from us
543  // but we can make 37 cents if we accept new coins from ourself
544  const auto result3 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 37 * CENT, CENT);
545  BOOST_CHECK(result3);
546  BOOST_CHECK_EQUAL(result3->GetSelectedValue(), 37 * CENT);
547  // and we can make 38 cents if we accept all new coins
548  const auto result4 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 38 * CENT, CENT);
549  BOOST_CHECK(result4);
550  BOOST_CHECK_EQUAL(result4->GetSelectedValue(), 38 * CENT);
551 
552  // try making 34 cents from 1,2,5,10,20 - we can't do it exactly
553  const auto result5 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 34 * CENT, CENT);
554  BOOST_CHECK(result5);
555  BOOST_CHECK_EQUAL(result5->GetSelectedValue(), 35 * CENT); // but 35 cents is closest
556  BOOST_CHECK_EQUAL(result5->GetInputSet().size(), 3U); // the best should be 20+10+5. it's incredibly unlikely the 1 or 2 got included (but possible)
557 
558  // when we try making 7 cents, the smaller coins (1,2,5) are enough. We should see just 2+5
559  const auto result6 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 7 * CENT, CENT);
560  BOOST_CHECK(result6);
561  BOOST_CHECK_EQUAL(result6->GetSelectedValue(), 7 * CENT);
562  BOOST_CHECK_EQUAL(result6->GetInputSet().size(), 2U);
563 
564  // when we try making 8 cents, the smaller coins (1,2,5) are exactly enough.
565  const auto result7 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 8 * CENT, CENT);
566  BOOST_CHECK(result7);
567  BOOST_CHECK(result7->GetSelectedValue() == 8 * CENT);
568  BOOST_CHECK_EQUAL(result7->GetInputSet().size(), 3U);
569 
570  // when we try making 9 cents, no subset of smaller coins is enough, and we get the next bigger coin (10)
571  const auto result8 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 9 * CENT, CENT);
572  BOOST_CHECK(result8);
573  BOOST_CHECK_EQUAL(result8->GetSelectedValue(), 10 * CENT);
574  BOOST_CHECK_EQUAL(result8->GetInputSet().size(), 1U);
575 
576  // now clear out the wallet and start again to test choosing between subsets of smaller coins and the next biggest coin
577  available_coins.Clear();
578 
579  add_coin(available_coins, *wallet, 6*CENT);
580  add_coin(available_coins, *wallet, 7*CENT);
581  add_coin(available_coins, *wallet, 8*CENT);
582  add_coin(available_coins, *wallet, 20*CENT);
583  add_coin(available_coins, *wallet, 30*CENT); // now we have 6+7+8+20+30 = 71 cents total
584 
585  // check that we have 71 and not 72
586  const auto result9 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 71 * CENT, CENT);
587  BOOST_CHECK(result9);
589 
590  // now try making 16 cents. the best smaller coins can do is 6+7+8 = 21; not as good at the next biggest coin, 20
591  const auto result10 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 16 * CENT, CENT);
592  BOOST_CHECK(result10);
593  BOOST_CHECK_EQUAL(result10->GetSelectedValue(), 20 * CENT); // we should get 20 in one coin
594  BOOST_CHECK_EQUAL(result10->GetInputSet().size(), 1U);
595 
596  add_coin(available_coins, *wallet, 5*CENT); // now we have 5+6+7+8+20+30 = 75 cents total
597 
598  // now if we try making 16 cents again, the smaller coins can make 5+6+7 = 18 cents, better than the next biggest coin, 20
599  const auto result11 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 16 * CENT, CENT);
600  BOOST_CHECK(result11);
601  BOOST_CHECK_EQUAL(result11->GetSelectedValue(), 18 * CENT); // we should get 18 in 3 coins
602  BOOST_CHECK_EQUAL(result11->GetInputSet().size(), 3U);
603 
604  add_coin(available_coins, *wallet, 18*CENT); // now we have 5+6+7+8+18+20+30
605 
606  // and now if we try making 16 cents again, the smaller coins can make 5+6+7 = 18 cents, the same as the next biggest coin, 18
607  const auto result12 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 16 * CENT, CENT);
608  BOOST_CHECK(result12);
609  BOOST_CHECK_EQUAL(result12->GetSelectedValue(), 18 * CENT); // we should get 18 in 1 coin
610  BOOST_CHECK_EQUAL(result12->GetInputSet().size(), 1U); // because in the event of a tie, the biggest coin wins
611 
612  // now try making 11 cents. we should get 5+6
613  const auto result13 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 11 * CENT, CENT);
614  BOOST_CHECK(result13);
615  BOOST_CHECK_EQUAL(result13->GetSelectedValue(), 11 * CENT);
616  BOOST_CHECK_EQUAL(result13->GetInputSet().size(), 2U);
617 
618  // check that the smallest bigger coin is used
619  add_coin(available_coins, *wallet, 1*COIN);
620  add_coin(available_coins, *wallet, 2*COIN);
621  add_coin(available_coins, *wallet, 3*COIN);
622  add_coin(available_coins, *wallet, 4*COIN); // now we have 5+6+7+8+18+20+30+100+200+300+400 = 1094 cents
623  const auto result14 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 95 * CENT, CENT);
624  BOOST_CHECK(result14);
625  BOOST_CHECK_EQUAL(result14->GetSelectedValue(), 1 * COIN); // we should get 1 BTC in 1 coin
626  BOOST_CHECK_EQUAL(result14->GetInputSet().size(), 1U);
627 
628  const auto result15 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 195 * CENT, CENT);
629  BOOST_CHECK(result15);
630  BOOST_CHECK_EQUAL(result15->GetSelectedValue(), 2 * COIN); // we should get 2 BTC in 1 coin
631  BOOST_CHECK_EQUAL(result15->GetInputSet().size(), 1U);
632 
633  // empty the wallet and start again, now with fractions of a cent, to test small change avoidance
634 
635  available_coins.Clear();
636  add_coin(available_coins, *wallet, CENT * 1 / 10);
637  add_coin(available_coins, *wallet, CENT * 2 / 10);
638  add_coin(available_coins, *wallet, CENT * 3 / 10);
639  add_coin(available_coins, *wallet, CENT * 4 / 10);
640  add_coin(available_coins, *wallet, CENT * 5 / 10);
641 
642  // try making 1 * CENT from the 1.5 * CENT
643  // we'll get change smaller than CENT whatever happens, so can expect CENT exactly
644  const auto result16 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT, CENT);
645  BOOST_CHECK(result16);
646  BOOST_CHECK_EQUAL(result16->GetSelectedValue(), CENT);
647 
648  // but if we add a bigger coin, small change is avoided
649  add_coin(available_coins, *wallet, 1111*CENT);
650 
651  // try making 1 from 0.1 + 0.2 + 0.3 + 0.4 + 0.5 + 1111 = 1112.5
652  const auto result17 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
653  BOOST_CHECK(result17);
654  BOOST_CHECK_EQUAL(result17->GetSelectedValue(), 1 * CENT); // we should get the exact amount
655 
656  // if we add more small coins:
657  add_coin(available_coins, *wallet, CENT * 6 / 10);
658  add_coin(available_coins, *wallet, CENT * 7 / 10);
659 
660  // and try again to make 1.0 * CENT
661  const auto result18 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
662  BOOST_CHECK(result18);
663  BOOST_CHECK_EQUAL(result18->GetSelectedValue(), 1 * CENT); // we should get the exact amount
664 
665  // run the 'mtgox' test (see https://blockexplorer.com/tx/29a3efd3ef04f9153d47a990bd7b048a4b2d213daaa5fb8ed670fb85f13bdbcf)
666  // they tried to consolidate 10 50k coins into one 500k coin, and ended up with 50k in change
667  available_coins.Clear();
668  for (int j = 0; j < 20; j++)
669  add_coin(available_coins, *wallet, 50000 * COIN);
670 
671  const auto result19 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 500000 * COIN, CENT);
672  BOOST_CHECK(result19);
673  BOOST_CHECK_EQUAL(result19->GetSelectedValue(), 500000 * COIN); // we should get the exact amount
674  BOOST_CHECK_EQUAL(result19->GetInputSet().size(), 10U); // in ten coins
675 
676  // if there's not enough in the smaller coins to make at least 1 * CENT change (0.5+0.6+0.7 < 1.0+1.0),
677  // we need to try finding an exact subset anyway
678 
679  // sometimes it will fail, and so we use the next biggest coin:
680  available_coins.Clear();
681  add_coin(available_coins, *wallet, CENT * 5 / 10);
682  add_coin(available_coins, *wallet, CENT * 6 / 10);
683  add_coin(available_coins, *wallet, CENT * 7 / 10);
684  add_coin(available_coins, *wallet, 1111 * CENT);
685  const auto result20 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
686  BOOST_CHECK(result20);
687  BOOST_CHECK_EQUAL(result20->GetSelectedValue(), 1111 * CENT); // we get the bigger coin
688  BOOST_CHECK_EQUAL(result20->GetInputSet().size(), 1U);
689 
690  // but sometimes it's possible, and we use an exact subset (0.4 + 0.6 = 1.0)
691  available_coins.Clear();
692  add_coin(available_coins, *wallet, CENT * 4 / 10);
693  add_coin(available_coins, *wallet, CENT * 6 / 10);
694  add_coin(available_coins, *wallet, CENT * 8 / 10);
695  add_coin(available_coins, *wallet, 1111 * CENT);
696  const auto result21 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT, CENT);
697  BOOST_CHECK(result21);
698  BOOST_CHECK_EQUAL(result21->GetSelectedValue(), CENT); // we should get the exact amount
699  BOOST_CHECK_EQUAL(result21->GetInputSet().size(), 2U); // in two coins 0.4+0.6
700 
701  // test avoiding small change
702  available_coins.Clear();
703  add_coin(available_coins, *wallet, CENT * 5 / 100);
704  add_coin(available_coins, *wallet, CENT * 1);
705  add_coin(available_coins, *wallet, CENT * 100);
706 
707  // trying to make 100.01 from these three coins
708  const auto result22 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT * 10001 / 100, CENT);
709  BOOST_CHECK(result22);
710  BOOST_CHECK_EQUAL(result22->GetSelectedValue(), CENT * 10105 / 100); // we should get all coins
711  BOOST_CHECK_EQUAL(result22->GetInputSet().size(), 3U);
712 
713  // but if we try to make 99.9, we should take the bigger of the two small coins to avoid small change
714  const auto result23 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT * 9990 / 100, CENT);
715  BOOST_CHECK(result23);
716  BOOST_CHECK_EQUAL(result23->GetSelectedValue(), 101 * CENT);
717  BOOST_CHECK_EQUAL(result23->GetInputSet().size(), 2U);
718  }
719 
720  // test with many inputs
721  for (CAmount amt=1500; amt < COIN; amt*=10) {
722  available_coins.Clear();
723  // Create 676 inputs (= (old MAX_STANDARD_TX_SIZE == 100000) / 148 bytes per input)
724  for (uint16_t j = 0; j < 676; j++)
725  add_coin(available_coins, *wallet, amt);
726 
727  // We only create the wallet once to save time, but we still run the coin selection RUN_TESTS times.
728  for (int i = 0; i < RUN_TESTS; i++) {
729  const auto result24 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 2000, CENT);
730  BOOST_CHECK(result24);
731 
732  if (amt - 2000 < CENT) {
733  // needs more than one input:
734  uint16_t returnSize = std::ceil((2000.0 + CENT)/amt);
735  CAmount returnValue = amt * returnSize;
736  BOOST_CHECK_EQUAL(result24->GetSelectedValue(), returnValue);
737  BOOST_CHECK_EQUAL(result24->GetInputSet().size(), returnSize);
738  } else {
739  // one input is sufficient:
740  BOOST_CHECK_EQUAL(result24->GetSelectedValue(), amt);
741  BOOST_CHECK_EQUAL(result24->GetInputSet().size(), 1U);
742  }
743  }
744  }
745 
746  // test randomness
747  {
748  available_coins.Clear();
749  for (int i2 = 0; i2 < 100; i2++)
750  add_coin(available_coins, *wallet, COIN);
751 
752  // Again, we only create the wallet once to save time, but we still run the coin selection RUN_TESTS times.
753  for (int i = 0; i < RUN_TESTS; i++) {
754  // picking 50 from 100 coins doesn't depend on the shuffle,
755  // but does depend on randomness in the stochastic approximation code
756  const auto result25 = KnapsackSolver(GroupCoins(available_coins.All()), 50 * COIN, CENT);
757  BOOST_CHECK(result25);
758  const auto result26 = KnapsackSolver(GroupCoins(available_coins.All()), 50 * COIN, CENT);
759  BOOST_CHECK(result26);
760  BOOST_CHECK(!EqualResult(*result25, *result26));
761 
762  int fails = 0;
763  for (int j = 0; j < RANDOM_REPEATS; j++)
764  {
765  // Test that the KnapsackSolver selects randomly from equivalent coins (same value and same input size).
766  // When choosing 1 from 100 identical coins, 1% of the time, this test will choose the same coin twice
767  // which will cause it to fail.
768  // To avoid that issue, run the test RANDOM_REPEATS times and only complain if all of them fail
769  const auto result27 = KnapsackSolver(GroupCoins(available_coins.All()), COIN, CENT);
770  BOOST_CHECK(result27);
771  const auto result28 = KnapsackSolver(GroupCoins(available_coins.All()), COIN, CENT);
772  BOOST_CHECK(result28);
773  if (EqualResult(*result27, *result28))
774  fails++;
775  }
776  BOOST_CHECK_NE(fails, RANDOM_REPEATS);
777  }
778 
779  // add 75 cents in small change. not enough to make 90 cents,
780  // then try making 90 cents. there are multiple competing "smallest bigger" coins,
781  // one of which should be picked at random
782  add_coin(available_coins, *wallet, 5 * CENT);
783  add_coin(available_coins, *wallet, 10 * CENT);
784  add_coin(available_coins, *wallet, 15 * CENT);
785  add_coin(available_coins, *wallet, 20 * CENT);
786  add_coin(available_coins, *wallet, 25 * CENT);
787 
788  for (int i = 0; i < RUN_TESTS; i++) {
789  int fails = 0;
790  for (int j = 0; j < RANDOM_REPEATS; j++)
791  {
792  const auto result29 = KnapsackSolver(GroupCoins(available_coins.All()), 90 * CENT, CENT);
793  BOOST_CHECK(result29);
794  const auto result30 = KnapsackSolver(GroupCoins(available_coins.All()), 90 * CENT, CENT);
795  BOOST_CHECK(result30);
796  if (EqualResult(*result29, *result30))
797  fails++;
798  }
799  BOOST_CHECK_NE(fails, RANDOM_REPEATS);
800  }
801  }
802 }
803 
805 {
806  FastRandomContext rand{};
807  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
808 
809  CoinsResult available_coins;
810 
811  // Test vValue sort order
812  for (int i = 0; i < 1000; i++)
813  add_coin(available_coins, *wallet, 1000 * COIN);
814  add_coin(available_coins, *wallet, 3 * COIN);
815 
816  const auto result = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 1003 * COIN, CENT, rand);
817  BOOST_CHECK(result);
818  BOOST_CHECK_EQUAL(result->GetSelectedValue(), 1003 * COIN);
819  BOOST_CHECK_EQUAL(result->GetInputSet().size(), 2U);
820 }
821 
822 // Tests that with the ideal conditions, the coin selector will always be able to find a solution that can pay the target value
823 BOOST_AUTO_TEST_CASE(SelectCoins_test)
824 {
825  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
826  LOCK(wallet->cs_wallet); // Every 'SelectCoins' call requires it
827 
828  // Random generator stuff
829  std::default_random_engine generator;
830  std::exponential_distribution<double> distribution (100);
831  FastRandomContext rand;
832 
833  // Run this test 100 times
834  for (int i = 0; i < 100; ++i)
835  {
836  CoinsResult available_coins;
837  CAmount balance{0};
838 
839  // Make a wallet with 1000 exponentially distributed random inputs
840  for (int j = 0; j < 1000; ++j)
841  {
842  CAmount val = distribution(generator)*10000000;
843  add_coin(available_coins, *wallet, val);
844  balance += val;
845  }
846 
847  // Generate a random fee rate in the range of 100 - 400
848  CFeeRate rate(rand.randrange(300) + 100);
849 
850  // Generate a random target value between 1000 and wallet balance
851  CAmount target = rand.randrange(balance - 1000) + 1000;
852 
853  // Perform selection
854  CoinSelectionParams cs_params{
855  rand,
856  /*change_output_size=*/ 34,
857  /*change_spend_size=*/ 148,
858  /*min_change_target=*/ CENT,
859  /*effective_feerate=*/ CFeeRate(0),
860  /*long_term_feerate=*/ CFeeRate(0),
861  /*discard_feerate=*/ CFeeRate(0),
862  /*tx_noinputs_size=*/ 0,
863  /*avoid_partial=*/ false,
864  };
865  cs_params.m_cost_of_change = 1;
866  cs_params.min_viable_change = 1;
867  CCoinControl cc;
868  const auto result = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, target, cc, cs_params);
869  BOOST_CHECK(result);
870  BOOST_CHECK_GE(result->GetSelectedValue(), target);
871  }
872 }
873 
875 {
876  const CAmount fee{100};
877  const CAmount min_viable_change{300};
878  const CAmount change_cost{125};
879  const CAmount change_fee{30};
880  const CAmount fee_diff{40};
881  const CAmount in_amt{3 * COIN};
882  const CAmount target{2 * COIN};
883  const CAmount excess{80};
884  const CAmount exact_target{in_amt - fee * 2}; // Maximum spendable amount after fees: no change, no excess
885 
886  // In the following, we test that the waste is calculated correctly in various scenarios.
887  // Usually, RecalculateWaste would compute change_fee and change_cost on basis of the
888  // change output type, current feerate, and discard_feerate, but we use fixed values
889  // across this test to make the test easier to understand.
890  {
891  // Waste with change is the change cost and difference between fee and long term fee
892  SelectionResult selection1{target, SelectionAlgorithm::MANUAL};
893  add_coin(1 * COIN, 1, selection1, /*fee=*/fee, /*long_term_fee=*/fee - fee_diff);
894  add_coin(2 * COIN, 2, selection1, fee, fee - fee_diff);
895  selection1.RecalculateWaste(min_viable_change, change_cost, change_fee);
896  BOOST_CHECK_EQUAL(fee_diff * 2 + change_cost, selection1.GetWaste());
897 
898  // Waste will be greater when fee is greater, but long term fee is the same
899  SelectionResult selection2{target, SelectionAlgorithm::MANUAL};
900  add_coin(1 * COIN, 1, selection2, fee * 2, fee - fee_diff);
901  add_coin(2 * COIN, 2, selection2, fee * 2, fee - fee_diff);
902  selection2.RecalculateWaste(min_viable_change, change_cost, change_fee);
903  BOOST_CHECK_GT(selection2.GetWaste(), selection1.GetWaste());
904 
905  // Waste with change is the change cost and difference between fee and long term fee
906  // With long term fee greater than fee, waste should be less than when long term fee is less than fee
907  SelectionResult selection3{target, SelectionAlgorithm::MANUAL};
908  add_coin(1 * COIN, 1, selection3, fee, fee + fee_diff);
909  add_coin(2 * COIN, 2, selection3, fee, fee + fee_diff);
910  selection3.RecalculateWaste(min_viable_change, change_cost, change_fee);
911  BOOST_CHECK_EQUAL(fee_diff * -2 + change_cost, selection3.GetWaste());
912  BOOST_CHECK_LT(selection3.GetWaste(), selection1.GetWaste());
913  }
914 
915  {
916  // Waste without change is the excess and difference between fee and long term fee
917  SelectionResult selection_nochange1{exact_target - excess, SelectionAlgorithm::MANUAL};
918  add_coin(1 * COIN, 1, selection_nochange1, fee, fee - fee_diff);
919  add_coin(2 * COIN, 2, selection_nochange1, fee, fee - fee_diff);
920  selection_nochange1.RecalculateWaste(min_viable_change, change_cost, change_fee);
921  BOOST_CHECK_EQUAL(fee_diff * 2 + excess, selection_nochange1.GetWaste());
922 
923  // Waste without change is the excess and difference between fee and long term fee
924  // With long term fee greater than fee, waste should be less than when long term fee is less than fee
925  SelectionResult selection_nochange2{exact_target - excess, SelectionAlgorithm::MANUAL};
926  add_coin(1 * COIN, 1, selection_nochange2, fee, fee + fee_diff);
927  add_coin(2 * COIN, 2, selection_nochange2, fee, fee + fee_diff);
928  selection_nochange2.RecalculateWaste(min_viable_change, change_cost, change_fee);
929  BOOST_CHECK_EQUAL(fee_diff * -2 + excess, selection_nochange2.GetWaste());
930  BOOST_CHECK_LT(selection_nochange2.GetWaste(), selection_nochange1.GetWaste());
931  }
932 
933  {
934  // Waste with change and fee == long term fee is just cost of change
935  SelectionResult selection{target, SelectionAlgorithm::MANUAL};
936  add_coin(1 * COIN, 1, selection, fee, fee);
937  add_coin(2 * COIN, 2, selection, fee, fee);
938  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
939  BOOST_CHECK_EQUAL(change_cost, selection.GetWaste());
940  }
941 
942  {
943  // Waste without change and fee == long term fee is just the excess
944  SelectionResult selection{exact_target - excess, SelectionAlgorithm::MANUAL};
945  add_coin(1 * COIN, 1, selection, fee, fee);
946  add_coin(2 * COIN, 2, selection, fee, fee);
947  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
948  BOOST_CHECK_EQUAL(excess, selection.GetWaste());
949  }
950 
951  {
952  // Waste is 0 when fee == long_term_fee, no change, and no excess
953  SelectionResult selection{exact_target, SelectionAlgorithm::MANUAL};
954  add_coin(1 * COIN, 1, selection, fee, fee);
955  add_coin(2 * COIN, 2, selection, fee, fee);
956  selection.RecalculateWaste(min_viable_change, change_cost , change_fee);
957  BOOST_CHECK_EQUAL(0, selection.GetWaste());
958  }
959 
960  {
961  // Waste is 0 when (fee - long_term_fee) == (-cost_of_change), and no excess
962  SelectionResult selection{target, SelectionAlgorithm::MANUAL};
963  add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
964  add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
965  selection.RecalculateWaste(min_viable_change, /*change_cost=*/fee_diff * 2, change_fee);
966  BOOST_CHECK_EQUAL(0, selection.GetWaste());
967  }
968 
969  {
970  // Waste is 0 when (fee - long_term_fee) == (-excess), no change cost
971  const CAmount new_target{exact_target - /*excess=*/fee_diff * 2};
972  SelectionResult selection{new_target, SelectionAlgorithm::MANUAL};
973  add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
974  add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
975  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
976  BOOST_CHECK_EQUAL(0, selection.GetWaste());
977  }
978 
979  {
980  // Negative waste when the long term fee is greater than the current fee and the selected value == target
981  SelectionResult selection{exact_target, SelectionAlgorithm::MANUAL};
982  const CAmount target_waste1{-2 * fee_diff}; // = (2 * fee) - (2 * (fee + fee_diff))
983  add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
984  add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
985  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
986  BOOST_CHECK_EQUAL(target_waste1, selection.GetWaste());
987  }
988 
989  {
990  // Negative waste when the long term fee is greater than the current fee and change_cost < - (inputs * (fee - long_term_fee))
991  SelectionResult selection{target, SelectionAlgorithm::MANUAL};
992  const CAmount large_fee_diff{90};
993  const CAmount target_waste2{-2 * large_fee_diff + change_cost};
994  // = (2 * fee) - (2 * (fee + large_fee_diff)) + change_cost
995  // = (2 * 100) - (2 * (100 + 90)) + 125
996  // = 200 - 380 + 125 = -55
997  assert(target_waste2 == -55);
998  add_coin(1 * COIN, 1, selection, fee, fee + large_fee_diff);
999  add_coin(2 * COIN, 2, selection, fee, fee + large_fee_diff);
1000  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
1001  BOOST_CHECK_EQUAL(target_waste2, selection.GetWaste());
1002  }
1003 }
1004 
1005 
1006 BOOST_AUTO_TEST_CASE(bump_fee_test)
1007 {
1008  const CAmount fee{100};
1009  const CAmount min_viable_change{200};
1010  const CAmount change_cost{125};
1011  const CAmount change_fee{35};
1012  const CAmount fee_diff{40};
1013  const CAmount target{2 * COIN};
1014 
1015  {
1016  SelectionResult selection{target, SelectionAlgorithm::MANUAL};
1017  add_coin(1 * COIN, 1, selection, /*fee=*/fee, /*long_term_fee=*/fee + fee_diff);
1018  add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
1019  const std::vector<std::shared_ptr<COutput>> inputs = selection.GetShuffledInputVector();
1020 
1021  for (size_t i = 0; i < inputs.size(); ++i) {
1022  inputs[i]->ApplyBumpFee(20*(i+1));
1023  }
1024 
1025  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
1026  CAmount expected_waste = fee_diff * -2 + change_cost + /*bump_fees=*/60;
1027  BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
1028 
1029  selection.SetBumpFeeDiscount(30);
1030  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
1031  expected_waste = fee_diff * -2 + change_cost + /*bump_fees=*/60 - /*group_discount=*/30;
1032  BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
1033  }
1034 
1035  {
1036  // Test with changeless transaction
1037  //
1038  // Bump fees and excess both contribute fully to the waste score,
1039  // therefore, a bump fee group discount will not change the waste
1040  // score as long as we do not create change in both instances.
1041  CAmount changeless_target = 3 * COIN - 2 * fee - 100;
1042  SelectionResult selection{changeless_target, SelectionAlgorithm::MANUAL};
1043  add_coin(1 * COIN, 1, selection, /*fee=*/fee, /*long_term_fee=*/fee + fee_diff);
1044  add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
1045  const std::vector<std::shared_ptr<COutput>> inputs = selection.GetShuffledInputVector();
1046 
1047  for (size_t i = 0; i < inputs.size(); ++i) {
1048  inputs[i]->ApplyBumpFee(20*(i+1));
1049  }
1050 
1051  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
1052  CAmount expected_waste = fee_diff * -2 + /*bump_fees=*/60 + /*excess = 100 - bump_fees*/40;
1053  BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
1054 
1055  selection.SetBumpFeeDiscount(30);
1056  selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
1057  expected_waste = fee_diff * -2 + /*bump_fees=*/60 - /*group_discount=*/30 + /*excess = 100 - bump_fees + group_discount*/70;
1058  BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
1059  }
1060 }
1061 
1062 BOOST_AUTO_TEST_CASE(effective_value_test)
1063 {
1064  const int input_bytes = 148;
1065  const CFeeRate feerate(1000);
1066  const CAmount nValue = 10000;
1067  const int nInput = 0;
1068 
1070  tx.vout.resize(1);
1071  tx.vout[nInput].nValue = nValue;
1072 
1073  // standard case, pass feerate in constructor
1074  COutput output1(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, input_bytes, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, feerate);
1075  const CAmount expected_ev1 = 9852; // 10000 - 148
1076  BOOST_CHECK_EQUAL(output1.GetEffectiveValue(), expected_ev1);
1077 
1078  // input bytes unknown (input_bytes = -1), pass feerate in constructor
1079  COutput output2(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, /*input_bytes=*/ -1, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, feerate);
1080  BOOST_CHECK_EQUAL(output2.GetEffectiveValue(), nValue); // The effective value should be equal to the absolute value if input_bytes is -1
1081 
1082  // negative effective value, pass feerate in constructor
1083  COutput output3(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, input_bytes, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, CFeeRate(100000));
1084  const CAmount expected_ev3 = -4800; // 10000 - 14800
1085  BOOST_CHECK_EQUAL(output3.GetEffectiveValue(), expected_ev3);
1086 
1087  // standard case, pass fees in constructor
1088  const CAmount fees = 148;
1089  COutput output4(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, input_bytes, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, fees);
1090  BOOST_CHECK_EQUAL(output4.GetEffectiveValue(), expected_ev1);
1091 
1092  // input bytes unknown (input_bytes = -1), pass fees in constructor
1093  COutput output5(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/ 1, /*input_bytes=*/ -1, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, /*fees=*/ 0);
1094  BOOST_CHECK_EQUAL(output5.GetEffectiveValue(), nValue); // The effective value should be equal to the absolute value if input_bytes is -1
1095 }
1096 
1098  const CoinSelectionParams& cs_params,
1099  const node::NodeContext& m_node,
1100  int max_weight,
1101  std::function<CoinsResult(CWallet&)> coin_setup)
1102 {
1103  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
1104  CoinEligibilityFilter filter(0, 0, 0); // accept all coins without ancestors
1105  Groups group = GroupOutputs(*wallet, coin_setup(*wallet), cs_params, {{filter}})[filter].all_groups;
1106  return CoinGrinder(group.positive_group, target, cs_params.m_min_change_target, max_weight);
1107 }
1108 
1109 BOOST_AUTO_TEST_CASE(coin_grinder_tests)
1110 {
1111  // Test Coin Grinder:
1112  // 1) Insufficient funds, select all provided coins and fail.
1113  // 2) Exceeded max weight, coin selection always surpasses the max allowed weight.
1114  // 3) Select coins without surpassing the max weight (some coins surpasses the max allowed weight, some others not)
1115  // 4) Test that two less valuable UTXOs with a combined lower weight are preferred over a more valuable heavier UTXO
1116  // 5) Test finding a solution in a UTXO pool with mixed weights
1117  // 6) Test that the lightest solution among many clones is found
1118  // 7) Test that lots of tiny UTXOs can be skipped if they are too heavy while there are enough funds in lookahead
1119 
1120  FastRandomContext rand;
1121  CoinSelectionParams dummy_params{ // Only used to provide the 'avoid_partial' flag.
1122  rand,
1123  /*change_output_size=*/34,
1124  /*change_spend_size=*/68,
1125  /*min_change_target=*/CENT,
1126  /*effective_feerate=*/CFeeRate(5000),
1127  /*long_term_feerate=*/CFeeRate(2000),
1128  /*discard_feerate=*/CFeeRate(1000),
1129  /*tx_noinputs_size=*/10 + 34, // static header size + output size
1130  /*avoid_partial=*/false,
1131  };
1132 
1133  {
1134  // #########################################################
1135  // 1) Insufficient funds, select all provided coins and fail
1136  // #########################################################
1137  CAmount target = 49.5L * COIN;
1138  int max_weight = 10'000; // high enough to not fail for this reason.
1139  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1140  CoinsResult available_coins;
1141  for (int j = 0; j < 10; ++j) {
1142  add_coin(available_coins, wallet, CAmount(1 * COIN));
1143  add_coin(available_coins, wallet, CAmount(2 * COIN));
1144  }
1145  return available_coins;
1146  });
1147  BOOST_CHECK(!res);
1148  BOOST_CHECK(util::ErrorString(res).empty()); // empty means "insufficient funds"
1149  }
1150 
1151  {
1152  // ###########################
1153  // 2) Test max weight exceeded
1154  // ###########################
1155  CAmount target = 29.5L * COIN;
1156  int max_weight = 3000;
1157  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1158  CoinsResult available_coins;
1159  for (int j = 0; j < 10; ++j) {
1160  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true);
1161  add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true);
1162  }
1163  return available_coins;
1164  });
1165  BOOST_CHECK(!res);
1166  BOOST_CHECK(util::ErrorString(res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
1167  }
1168 
1169  {
1170  // ###############################################################################################################
1171  // 3) Test selection when some coins surpass the max allowed weight while others not. --> must find a good solution
1172  // ################################################################################################################
1173  CAmount target = 25.33L * COIN;
1174  int max_weight = 10'000; // WU
1175  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1176  CoinsResult available_coins;
1177  for (int j = 0; j < 60; ++j) { // 60 UTXO --> 19,8 BTC total --> 60 × 272 WU = 16320 WU
1178  add_coin(available_coins, wallet, CAmount(0.33 * COIN), CFeeRate(5000), 144, false, 0, true);
1179  }
1180  for (int i = 0; i < 10; i++) { // 10 UTXO --> 20 BTC total --> 10 × 272 WU = 2720 WU
1181  add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true);
1182  }
1183  return available_coins;
1184  });
1185  BOOST_CHECK(res);
1186  // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
1187  size_t expected_attempts = 37;
1188  BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
1189  }
1190 
1191  {
1192  // #################################################################################################################
1193  // 4) Test that two less valuable UTXOs with a combined lower weight are preferred over a more valuable heavier UTXO
1194  // #################################################################################################################
1195  CAmount target = 1.9L * COIN;
1196  int max_weight = 400'000; // WU
1197  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1198  CoinsResult available_coins;
1199  add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true, 148);
1200  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 68);
1201  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 68);
1202  return available_coins;
1203  });
1204  SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
1205  add_coin(1 * COIN, 1, expected_result);
1206  add_coin(1 * COIN, 2, expected_result);
1207  BOOST_CHECK(EquivalentResult(expected_result, *res));
1208  // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
1209  size_t expected_attempts = 3;
1210  BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
1211  }
1212 
1213  {
1214  // ###############################################################################################################
1215  // 5) Test finding a solution in a UTXO pool with mixed weights
1216  // ################################################################################################################
1217  CAmount target = 30L * COIN;
1218  int max_weight = 400'000; // WU
1219  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1220  CoinsResult available_coins;
1221  for (int j = 0; j < 5; ++j) {
1222  // Add heavy coins {3, 6, 9, 12, 15}
1223  add_coin(available_coins, wallet, CAmount((3 + 3 * j) * COIN), CFeeRate(5000), 144, false, 0, true, 350);
1224  // Add medium coins {2, 5, 8, 11, 14}
1225  add_coin(available_coins, wallet, CAmount((2 + 3 * j) * COIN), CFeeRate(5000), 144, false, 0, true, 250);
1226  // Add light coins {1, 4, 7, 10, 13}
1227  add_coin(available_coins, wallet, CAmount((1 + 3 * j) * COIN), CFeeRate(5000), 144, false, 0, true, 150);
1228  }
1229  return available_coins;
1230  });
1231  BOOST_CHECK(res);
1232  SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
1233  add_coin(14 * COIN, 1, expected_result);
1234  add_coin(13 * COIN, 2, expected_result);
1235  add_coin(4 * COIN, 3, expected_result);
1236  BOOST_CHECK(EquivalentResult(expected_result, *res));
1237  // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
1238  size_t expected_attempts = 92;
1239  BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
1240  }
1241 
1242  {
1243  // #################################################################################################################
1244  // 6) Test that the lightest solution among many clones is found
1245  // #################################################################################################################
1246  CAmount target = 9.9L * COIN;
1247  int max_weight = 400'000; // WU
1248  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1249  CoinsResult available_coins;
1250  // Expected Result: 4 + 3 + 2 + 1 = 10 BTC at 400 vB
1251  add_coin(available_coins, wallet, CAmount(4 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
1252  add_coin(available_coins, wallet, CAmount(3 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
1253  add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
1254  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
1255  // Distracting clones:
1256  for (int j = 0; j < 100; ++j) {
1257  add_coin(available_coins, wallet, CAmount(8 * COIN), CFeeRate(5000), 144, false, 0, true, 1000);
1258  }
1259  for (int j = 0; j < 100; ++j) {
1260  add_coin(available_coins, wallet, CAmount(7 * COIN), CFeeRate(5000), 144, false, 0, true, 800);
1261  }
1262  for (int j = 0; j < 100; ++j) {
1263  add_coin(available_coins, wallet, CAmount(6 * COIN), CFeeRate(5000), 144, false, 0, true, 600);
1264  }
1265  for (int j = 0; j < 100; ++j) {
1266  add_coin(available_coins, wallet, CAmount(5 * COIN), CFeeRate(5000), 144, false, 0, true, 400);
1267  }
1268  return available_coins;
1269  });
1270  SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
1271  add_coin(4 * COIN, 0, expected_result);
1272  add_coin(3 * COIN, 0, expected_result);
1273  add_coin(2 * COIN, 0, expected_result);
1274  add_coin(1 * COIN, 0, expected_result);
1275  BOOST_CHECK(EquivalentResult(expected_result, *res));
1276  // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
1277  size_t expected_attempts = 38;
1278  BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
1279  }
1280 
1281  {
1282  // #################################################################################################################
1283  // 7) Test that lots of tiny UTXOs can be skipped if they are too heavy while there are enough funds in lookahead
1284  // #################################################################################################################
1285  CAmount target = 1.9L * COIN;
1286  int max_weight = 40000; // WU
1287  const auto& res = CoinGrinder(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1288  CoinsResult available_coins;
1289  add_coin(available_coins, wallet, CAmount(1.8 * COIN), CFeeRate(5000), 144, false, 0, true, 2500);
1290  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 1000);
1291  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 1000);
1292  for (int j = 0; j < 100; ++j) {
1293  // make a 100 unique coins only differing by one sat
1294  add_coin(available_coins, wallet, CAmount(0.01 * COIN + j), CFeeRate(5000), 144, false, 0, true, 110);
1295  }
1296  return available_coins;
1297  });
1298  SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
1299  add_coin(1 * COIN, 1, expected_result);
1300  add_coin(1 * COIN, 2, expected_result);
1301  BOOST_CHECK(EquivalentResult(expected_result, *res));
1302  // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
1303  size_t expected_attempts = 7;
1304  BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
1305  }
1306 }
1307 
1309  const CoinSelectionParams& cs_params,
1310  const node::NodeContext& m_node,
1311  int max_weight,
1312  std::function<CoinsResult(CWallet&)> coin_setup)
1313 {
1314  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
1315  CoinEligibilityFilter filter(0, 0, 0); // accept all coins without ancestors
1316  Groups group = GroupOutputs(*wallet, coin_setup(*wallet), cs_params, {{filter}})[filter].all_groups;
1317  return SelectCoinsSRD(group.positive_group, target, cs_params.m_change_fee, cs_params.rng_fast, max_weight);
1318 }
1319 
1321 {
1322  // Test SRD:
1323  // 1) Insufficient funds, select all provided coins and fail.
1324  // 2) Exceeded max weight, coin selection always surpasses the max allowed weight.
1325  // 3) Select coins without surpassing the max weight (some coins surpasses the max allowed weight, some others not)
1326 
1327  FastRandomContext rand;
1328  CoinSelectionParams dummy_params{ // Only used to provide the 'avoid_partial' flag.
1329  rand,
1330  /*change_output_size=*/34,
1331  /*change_spend_size=*/68,
1332  /*min_change_target=*/CENT,
1333  /*effective_feerate=*/CFeeRate(0),
1334  /*long_term_feerate=*/CFeeRate(0),
1335  /*discard_feerate=*/CFeeRate(0),
1336  /*tx_noinputs_size=*/10 + 34, // static header size + output size
1337  /*avoid_partial=*/false,
1338  };
1339 
1340  {
1341  // #########################################################
1342  // 1) Insufficient funds, select all provided coins and fail
1343  // #########################################################
1344  CAmount target = 49.5L * COIN;
1345  int max_weight = 10000; // high enough to not fail for this reason.
1346  const auto& res = SelectCoinsSRD(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1347  CoinsResult available_coins;
1348  for (int j = 0; j < 10; ++j) {
1349  add_coin(available_coins, wallet, CAmount(1 * COIN));
1350  add_coin(available_coins, wallet, CAmount(2 * COIN));
1351  }
1352  return available_coins;
1353  });
1354  BOOST_CHECK(!res);
1355  BOOST_CHECK(util::ErrorString(res).empty()); // empty means "insufficient funds"
1356  }
1357 
1358  {
1359  // ###########################
1360  // 2) Test max weight exceeded
1361  // ###########################
1362  CAmount target = 49.5L * COIN;
1363  int max_weight = 3000;
1364  const auto& res = SelectCoinsSRD(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1365  CoinsResult available_coins;
1366  for (int j = 0; j < 10; ++j) {
1367  /* 10 × 1 BTC + 10 × 2 BTC = 30 BTC. 20 × 272 WU = 5440 WU */
1368  add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(0), 144, false, 0, true);
1369  add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(0), 144, false, 0, true);
1370  }
1371  return available_coins;
1372  });
1373  BOOST_CHECK(!res);
1374  BOOST_CHECK(util::ErrorString(res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
1375  }
1376 
1377  {
1378  // ################################################################################################################
1379  // 3) Test selection when some coins surpass the max allowed weight while others not. --> must find a good solution
1380  // ################################################################################################################
1381  CAmount target = 25.33L * COIN;
1382  int max_weight = 10000; // WU
1383  const auto& res = SelectCoinsSRD(target, dummy_params, m_node, max_weight, [&](CWallet& wallet) {
1384  CoinsResult available_coins;
1385  for (int j = 0; j < 60; ++j) { // 60 UTXO --> 19,8 BTC total --> 60 × 272 WU = 16320 WU
1386  add_coin(available_coins, wallet, CAmount(0.33 * COIN), CFeeRate(0), 144, false, 0, true);
1387  }
1388  for (int i = 0; i < 10; i++) { // 10 UTXO --> 20 BTC total --> 10 × 272 WU = 2720 WU
1389  add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(0), 144, false, 0, true);
1390  }
1391  return available_coins;
1392  });
1393  BOOST_CHECK(res);
1394  }
1395 }
1396 
1397 static util::Result<SelectionResult> select_coins(const CAmount& target, const CoinSelectionParams& cs_params, const CCoinControl& cc, std::function<CoinsResult(CWallet&)> coin_setup, const node::NodeContext& m_node)
1398 {
1399  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
1400  auto available_coins = coin_setup(*wallet);
1401 
1402  LOCK(wallet->cs_wallet);
1403  auto result = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/ {}, target, cc, cs_params);
1404  if (result) {
1405  const auto signedTxSize = 10 + 34 + 68 * result->GetInputSet().size(); // static header size + output size + inputs size (P2WPKH)
1406  BOOST_CHECK_LE(signedTxSize * WITNESS_SCALE_FACTOR, MAX_STANDARD_TX_WEIGHT);
1407 
1408  BOOST_CHECK_GE(result->GetSelectedValue(), target);
1409  }
1410  return result;
1411 }
1412 
1413 static bool has_coin(const CoinSet& set, CAmount amount)
1414 {
1415  return std::any_of(set.begin(), set.end(), [&](const auto& coin) { return coin->GetEffectiveValue() == amount; });
1416 }
1417 
1418 BOOST_AUTO_TEST_CASE(check_max_weight)
1419 {
1420  const CAmount target = 49.5L * COIN;
1421  CCoinControl cc;
1422 
1423  FastRandomContext rand;
1424  CoinSelectionParams cs_params{
1425  rand,
1426  /*change_output_size=*/34,
1427  /*change_spend_size=*/68,
1428  /*min_change_target=*/CENT,
1429  /*effective_feerate=*/CFeeRate(0),
1430  /*long_term_feerate=*/CFeeRate(0),
1431  /*discard_feerate=*/CFeeRate(0),
1432  /*tx_noinputs_size=*/10 + 34, // static header size + output size
1433  /*avoid_partial=*/false,
1434  };
1435 
1436  int max_weight = MAX_STANDARD_TX_WEIGHT - WITNESS_SCALE_FACTOR * (cs_params.tx_noinputs_size + cs_params.change_output_size);
1437  {
1438  // Scenario 1:
1439  // The actor starts with 1x 50.0 BTC and 1515x 0.033 BTC (~100.0 BTC total) unspent outputs
1440  // Then tries to spend 49.5 BTC
1441  // The 50.0 BTC output should be selected, because the transaction would otherwise be too large
1442 
1443  // Perform selection
1444 
1445  const auto result = select_coins(
1446  target, cs_params, cc, [&](CWallet& wallet) {
1447  CoinsResult available_coins;
1448  for (int j = 0; j < 1515; ++j) {
1449  add_coin(available_coins, wallet, CAmount(0.033 * COIN), CFeeRate(0), 144, false, 0, true);
1450  }
1451 
1452  add_coin(available_coins, wallet, CAmount(50 * COIN), CFeeRate(0), 144, false, 0, true);
1453  return available_coins;
1454  },
1455  m_node);
1456 
1457  BOOST_CHECK(result);
1458  // Verify that the 50 BTC UTXO was selected, and result is below max_weight
1459  BOOST_CHECK(has_coin(result->GetInputSet(), CAmount(50 * COIN)));
1460  BOOST_CHECK_LE(result->GetWeight(), max_weight);
1461  }
1462 
1463  {
1464  // Scenario 2:
1465 
1466  // The actor starts with 400x 0.0625 BTC and 2000x 0.025 BTC (75.0 BTC total) unspent outputs
1467  // Then tries to spend 49.5 BTC
1468  // A combination of coins should be selected, such that the created transaction is not too large
1469 
1470  // Perform selection
1471  const auto result = select_coins(
1472  target, cs_params, cc, [&](CWallet& wallet) {
1473  CoinsResult available_coins;
1474  for (int j = 0; j < 400; ++j) {
1475  add_coin(available_coins, wallet, CAmount(0.0625 * COIN), CFeeRate(0), 144, false, 0, true);
1476  }
1477  for (int j = 0; j < 2000; ++j) {
1478  add_coin(available_coins, wallet, CAmount(0.025 * COIN), CFeeRate(0), 144, false, 0, true);
1479  }
1480  return available_coins;
1481  },
1482  m_node);
1483 
1484  BOOST_CHECK(has_coin(result->GetInputSet(), CAmount(0.0625 * COIN)));
1485  BOOST_CHECK(has_coin(result->GetInputSet(), CAmount(0.025 * COIN)));
1486  BOOST_CHECK_LE(result->GetWeight(), max_weight);
1487  }
1488 
1489  {
1490  // Scenario 3:
1491 
1492  // The actor starts with 1515x 0.033 BTC (49.995 BTC total) unspent outputs
1493  // No results should be returned, because the transaction would be too large
1494 
1495  // Perform selection
1496  const auto result = select_coins(
1497  target, cs_params, cc, [&](CWallet& wallet) {
1498  CoinsResult available_coins;
1499  for (int j = 0; j < 1515; ++j) {
1500  add_coin(available_coins, wallet, CAmount(0.033 * COIN), CFeeRate(0), 144, false, 0, true);
1501  }
1502  return available_coins;
1503  },
1504  m_node);
1505 
1506  // No results
1507  // 1515 inputs * 68 bytes = 103,020 bytes
1508  // 103,020 bytes * 4 = 412,080 weight, which is above the MAX_STANDARD_TX_WEIGHT of 400,000
1509  BOOST_CHECK(!result);
1510  }
1511 }
1512 
1513 BOOST_AUTO_TEST_CASE(SelectCoins_effective_value_test)
1514 {
1515  // Test that the effective value is used to check whether preset inputs provide sufficient funds when subtract_fee_outputs is not used.
1516  // This test creates a coin whose value is higher than the target but whose effective value is lower than the target.
1517  // The coin is selected using coin control, with m_allow_other_inputs = false. SelectCoins should fail due to insufficient funds.
1518 
1519  std::unique_ptr<CWallet> wallet = NewWallet(m_node);
1520 
1521  CoinsResult available_coins;
1522  {
1523  std::unique_ptr<CWallet> dummyWallet = NewWallet(m_node, /*wallet_name=*/"dummy");
1524  add_coin(available_coins, *dummyWallet, 100000); // 0.001 BTC
1525  }
1526 
1527  CAmount target{99900}; // 0.000999 BTC
1528 
1529  FastRandomContext rand;
1530  CoinSelectionParams cs_params{
1531  rand,
1532  /*change_output_size=*/34,
1533  /*change_spend_size=*/148,
1534  /*min_change_target=*/1000,
1535  /*effective_feerate=*/CFeeRate(3000),
1536  /*long_term_feerate=*/CFeeRate(1000),
1537  /*discard_feerate=*/CFeeRate(1000),
1538  /*tx_noinputs_size=*/0,
1539  /*avoid_partial=*/false,
1540  };
1541  CCoinControl cc;
1542  cc.m_allow_other_inputs = false;
1543  COutput output = available_coins.All().at(0);
1544  cc.SetInputWeight(output.outpoint, 148);
1545  cc.Select(output.outpoint).SetTxOut(output.txout);
1546 
1547  LOCK(wallet->cs_wallet);
1548  const auto preset_inputs = *Assert(FetchSelectedInputs(*wallet, cc, cs_params));
1549  available_coins.Erase({available_coins.coins[OutputType::BECH32].begin()->outpoint});
1550 
1551  const auto result = SelectCoins(*wallet, available_coins, preset_inputs, target, cc, cs_params);
1552  BOOST_CHECK(!result);
1553 }
1554 
1556 {
1557  // Test case to verify CoinsResult object sanity.
1558  CoinsResult available_coins;
1559  {
1560  std::unique_ptr<CWallet> dummyWallet = NewWallet(m_node, /*wallet_name=*/"dummy");
1561 
1562  // Add some coins to 'available_coins'
1563  for (int i=0; i<10; i++) {
1564  add_coin(available_coins, *dummyWallet, 1 * COIN);
1565  }
1566  }
1567 
1568  {
1569  // First test case, check that 'CoinsResult::Erase' function works as expected.
1570  // By trying to erase two elements from the 'available_coins' object.
1571  std::unordered_set<COutPoint, SaltedOutpointHasher> outs_to_remove;
1572  const auto& coins = available_coins.All();
1573  for (int i = 0; i < 2; i++) {
1574  outs_to_remove.emplace(coins[i].outpoint);
1575  }
1576  available_coins.Erase(outs_to_remove);
1577 
1578  // Check that the elements were actually removed.
1579  const auto& updated_coins = available_coins.All();
1580  for (const auto& out: outs_to_remove) {
1581  auto it = std::find_if(updated_coins.begin(), updated_coins.end(), [&out](const COutput &coin) {
1582  return coin.outpoint == out;
1583  });
1584  BOOST_CHECK(it == updated_coins.end());
1585  }
1586  // And verify that no extra element were removed
1587  BOOST_CHECK_EQUAL(available_coins.Size(), 8);
1588  }
1589 }
1590 
1592 } // namespace wallet
CScript GetScriptForDestination(const CTxDestination &dest)
Generate a Bitcoin scriptPubKey for the given CTxDestination.
int64_t CAmount
Amount in satoshis (Can be negative)
Definition: amount.h:12
static constexpr CAmount COIN
The amount of satoshis in one BTC.
Definition: amount.h:15
int ret
node::NodeContext m_node
Definition: bitcoin-gui.cpp:37
#define Assert(val)
Identity function.
Definition: check.h:77
Fee rate in satoshis per kilovirtualbyte: CAmount / kvB.
Definition: feerate.h:33
CAmount GetFee(uint32_t num_bytes) const
Return the fee in satoshis for the given vsize in vbytes.
Definition: feerate.cpp:23
An outpoint - a combination of a transaction hash and an index n into its vout.
Definition: transaction.h:29
Fast randomness source.
Definition: random.h:145
uint64_t randrange(uint64_t range) noexcept
Generate a random integer in the range [0..range).
Definition: random.h:203
256-bit opaque blob.
Definition: uint256.h:106
Coin Control Features.
Definition: coincontrol.h:81
PreselectedInput & Select(const COutPoint &outpoint)
Lock-in the given output for spending.
Definition: coincontrol.cpp:40
bool m_allow_other_inputs
If true, the selection process can add extra unselected inputs from the wallet while requires all sel...
Definition: coincontrol.h:91
void SetInputWeight(const COutPoint &outpoint, int64_t weight)
Set an input's weight.
Definition: coincontrol.cpp:67
A CWallet maintains a set of transactions and balances, and provides the ability to create new transa...
Definition: wallet.h:301
A transaction with a bunch of additional info that only the owner cares about.
Definition: transaction.h:177
const Txid & GetHash() const LIFETIMEBOUND
Definition: transaction.h:351
CTransactionRef tx
Definition: transaction.h:258
int64_t GetTxTime() const
Definition: transaction.cpp:26
void SetTxOut(const CTxOut &txout)
Set the previous output for this input.
Definition: coincontrol.cpp:90
#define RANDOM_REPEATS
#define RUN_TESTS
static const int WITNESS_SCALE_FACTOR
Definition: consensus.h:21
BOOST_AUTO_TEST_SUITE_END()
bilingual_str ErrorString(const Result< T > &result)
Definition: result.h:93
std::vector< OutputGroup > & KnapsackGroupOutputs(const CoinsResult &available_coins, CWallet &wallet, const CoinEligibilityFilter &filter)
util::Result< SelectionResult > SelectCoinsBnB(std::vector< OutputGroup > &utxo_pool, const CAmount &selection_target, const CAmount &cost_of_change, int max_weight)
static CAmount make_hard_case(int utxos, std::vector< COutput > &utxo_pool)
static const CoinEligibilityFilter filter_standard(1, 6, 0)
FilteredOutputGroups GroupOutputs(const CWallet &wallet, const CoinsResult &coins, const CoinSelectionParams &coin_sel_params, const std::vector< SelectionFilter > &filters, std::vector< OutputGroup > &ret_discarded_groups)
Definition: spend.cpp:524
BOOST_FIXTURE_TEST_CASE(wallet_coinsresult_test, BasicTestingSetup)
static void add_coin(const CAmount &nValue, int nInput, std::vector< COutput > &set)
util::Result< SelectionResult > CoinGrinder(std::vector< OutputGroup > &utxo_pool, const CAmount &selection_target, CAmount change_target, int max_weight)
util::Result< PreSelectedInputs > FetchSelectedInputs(const CWallet &wallet, const CCoinControl &coin_control, const CoinSelectionParams &coin_selection_params) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
Fetch and validate coin control selected inputs.
Definition: spend.cpp:258
static void ApproximateBestSubset(FastRandomContext &insecure_rand, const std::vector< OutputGroup > &groups, const CAmount &nTotalLower, const CAmount &nTargetValue, std::vector< char > &vfBest, CAmount &nBest, int iterations=1000)
Find a subset of the OutputGroups that is at least as large as, but as close as possible to,...
std::vector< OutputGroup > & GroupCoins(const std::vector< COutput > &available_coins, bool subtract_fee_outputs=false)
util::Result< SelectionResult > KnapsackSolver(std::vector< OutputGroup > &groups, const CAmount &nTargetValue, CAmount change_target, FastRandomContext &rng, int max_weight)
static std::unique_ptr< CWallet > NewWallet(const node::NodeContext &m_node, const std::string &wallet_name="")
util::Result< SelectionResult > SelectCoins(const CWallet &wallet, CoinsResult &available_coins, const PreSelectedInputs &pre_set_inputs, const CAmount &nTargetValue, const CCoinControl &coin_control, const CoinSelectionParams &coin_selection_params)
Select all coins from coin_control, and if coin_control 'm_allow_other_inputs=true',...
Definition: spend.cpp:757
static const CoinEligibilityFilter filter_standard_extra(6, 6, 0)
util::Result< SelectionResult > SelectCoinsSRD(const std::vector< OutputGroup > &utxo_pool, CAmount target_value, CAmount change_fee, FastRandomContext &rng, int max_weight)
Select coins by Single Random Draw.
static bool has_coin(const CoinSet &set, CAmount amount)
std::set< std::shared_ptr< COutput > > CoinSet
static bool EqualResult(const SelectionResult &a, const SelectionResult &b)
Check if this selection is equal to another one.
std::unique_ptr< WalletDatabase > CreateMockableWalletDatabase(MockableData records)
Definition: util.cpp:185
static util::Result< SelectionResult > select_coins(const CAmount &target, const CoinSelectionParams &cs_params, const CCoinControl &cc, std::function< CoinsResult(CWallet &)> coin_setup, const node::NodeContext &m_node)
BOOST_AUTO_TEST_CASE(bnb_search_test)
@ WALLET_FLAG_DESCRIPTORS
Indicate that this wallet supports DescriptorScriptPubKeyMan.
Definition: walletutil.h:74
static int nextLockTime
static const CoinEligibilityFilter filter_confirmed(1, 1, 0)
int CalculateMaximumSignedInputSize(const CTxOut &txout, const COutPoint outpoint, const SigningProvider *provider, bool can_grind_r, const CCoinControl *coin_control)
Definition: spend.cpp:81
static bool EquivalentResult(const SelectionResult &a, const SelectionResult &b)
Check if SelectionResult a is equivalent to SelectionResult b.
std::shared_ptr< CWallet > wallet
#define BOOST_CHECK_EQUAL(v1, v2)
Definition: object.cpp:18
#define BOOST_CHECK(expr)
Definition: object.cpp:17
static constexpr int32_t MAX_STANDARD_TX_WEIGHT
The maximum weight for transactions we're willing to relay/mine.
Definition: policy.h:27
static CTransactionRef MakeTransactionRef(Tx &&txIn)
Definition: transaction.h:424
static constexpr CAmount CENT
Definition: setup_common.h:49
Basic testing setup.
Definition: setup_common.h:54
A mutable version of CTransaction.
Definition: transaction.h:378
std::vector< CTxOut > vout
Definition: transaction.h:380
Txid GetHash() const
Compute the hash of this CMutableTransaction.
Definition: transaction.cpp:69
NodeContext struct containing references to chain state and connection state.
Definition: context.h:53
std::unique_ptr< interfaces::Chain > chain
Definition: context.h:71
A UTXO under consideration for use in funding a new transaction.
Definition: coinselection.h:28
COutPoint outpoint
The outpoint identifying this UTXO.
Definition: coinselection.h:38
CTxOut txout
The output itself.
Definition: coinselection.h:41
CAmount GetEffectiveValue() const
Parameters for filtering which OutputGroups we may use in coin selection.
Parameters for one iteration of Coin Selection.
FastRandomContext & rng_fast
Randomness to use in the context of coin selection.
CAmount m_min_change_target
Mininmum change to target in Knapsack solver and CoinGrinder: select coins to cover the payment and a...
size_t change_output_size
Size of a change output in bytes, determined by the output type.
CAmount m_change_fee
Cost of creating the change output.
size_t tx_noinputs_size
Size of the transaction before coin selection, consisting of the header and recipient output(s),...
COutputs available for spending, stored by OutputType.
Definition: spend.h:40
void Add(OutputType type, const COutput &out)
Definition: spend.cpp:229
std::vector< COutput > All() const
Concatenate and return all COutputs as one vector.
Definition: spend.cpp:192
size_t Size() const
The following methods are provided so that CoinsResult can mimic a vector, i.e., methods can work wit...
Definition: spend.cpp:183
std::map< OutputType, std::vector< COutput > > coins
Definition: spend.h:41
void Erase(const std::unordered_set< COutPoint, SaltedOutpointHasher > &coins_to_remove)
Definition: spend.cpp:206
std::vector< OutputGroup > mixed_group
A group of UTXOs paid to the same output script.
Stores several 'Groups' whose were mapped by output type.
void Insert(const COutput &output, bool subtract_fee_outputs)
Definition: spend.h:164
const std::set< std::shared_ptr< COutput > > & GetInputSet() const
Get m_selected_inputs.
void AddInput(const OutputGroup &group)
State of transaction not confirmed or conflicting with a known block and not in the mempool.
Definition: transaction.h:58
#define LOCK(cs)
Definition: sync.h:257
#define WITH_LOCK(cs, code)
Run code while locking a mutex.
Definition: sync.h:301
#define strprintf
Format arguments and return the string or write to given std::ostream (see tinyformat::format doc for...
Definition: tinyformat.h:1162
assert(!tx.IsCoinBase())