add allow any fee config

Tom Trevethan · Tom Trevethan · commit 31741b339d51 · 2025-07-18T15:40:04.000+01:00
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
@@ -898,6 +898,8 @@ class CCustomParams : public CRegTestParams {
         std::vector<unsigned char> man_bytes = ParseHex(args.GetArg("-con_mandatorycoinbase", ""));
         consensus.mandatory_coinbase_destination = CScript(man_bytes.begin(), man_bytes.end()); // Blank script allows any coinbase destination
 
+        consensus.allow_any_fee = args.GetBoolArg("-con_allow_any_fee", consensus.allow_any_fee);
+
         // Custom chains connect coinbase outputs to db by default
         consensus.connect_genesis_outputs = args.GetIntArg("-con_connect_genesis_outputs", true);
 
@@ -1515,6 +1517,8 @@ class CLiquidV1TestParams : public CLiquidV1Params {
             consensus.mandatory_coinbase_destination = CScript(man_bytes.begin(), man_bytes.end()); // Blank script allows any coinbase destination
         }
 
+        consensus.allow_any_fee = args.GetBoolArg("-con_allow_any_fee", consensus.allow_any_fee);
+
         consensus.connect_genesis_outputs = args.GetIntArg("-con_connect_genesis_outputs", consensus.connect_genesis_outputs);
 
         initialFreeCoins = args.GetIntArg("-initialfreecoins", initialFreeCoins);
diff --git a/src/chainparamsbase.cpp b/src/chainparamsbase.cpp
@@ -45,6 +45,7 @@ void SetupChainParamsBaseOptions(ArgsManager& argsman)
     argsman.AddArg("-con_signed_blocks", "Signed blockchain. Uses input of `-signblockscript` to define what signatures are necessary to solve it.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-signblockscript", "Signed blockchain enumberance. Only active when `-con_signed_blocks` set to true.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-con_max_block_sig_size", "Max allowed witness data for the signed block header.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
+    argsman.AddArg("-con_allow_any_fee", "Allow any fee value for any asset", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
 
     argsman.AddArg("-con_has_parent_chain", "Whether or not there is a parent chain.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-parentgenesisblockhash", "The genesis blockhash of the parent chain.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
diff --git a/src/confidential_validation.cpp b/src/confidential_validation.cpp
@@ -24,16 +24,20 @@ class CSecp256k1Init {
 static CSecp256k1Init instance_of_csecp256k1;
 }
 
-bool HasValidFee(const CTransaction& tx) {
+bool HasValidFee(const CTransaction& tx, bool allow_any_fee) {
     CAmountMap totalFee;
     for (unsigned int i = 0; i < tx.vout.size(); i++) {
         CAmount fee = 0;
         if (tx.vout[i].IsFee()) {
             fee = tx.vout[i].nValue.GetAmount();
-            if (fee == 0 || !MoneyRange(fee))
+            if (!allow_any_fee && (fee == 0 || !MoneyRange(fee))) {
                 return false;
+            }
             totalFee[tx.vout[i].nAsset.GetAsset()] += fee;
-            if (!MoneyRange(totalFee)) {
+            if (!allow_any_fee && !MoneyRange(totalFee)) {
+                return false;
+            }
+            if(allow_any_fee && fee < 0) {
                 return false;
             }
         }
diff --git a/src/confidential_validation.h b/src/confidential_validation.h
@@ -15,7 +15,7 @@
 
 
 // Check if explicit TX fees overflow or are negative
-bool HasValidFee(const CTransaction& tx);
+bool HasValidFee(const CTransaction& tx, bool allow_any_fee);
 
 // Compute the fee from the explicit fee outputs. Must call HasValidFee first
 CAmountMap GetFeeMap(const CTransaction& tx);
diff --git a/src/consensus/params.h b/src/consensus/params.h
@@ -175,6 +175,7 @@ struct Params {
     size_t total_valid_epochs = 1;
     bool elements_mode = false;
     bool start_p2wsh_script = false;
+    bool allow_any_fee = false;
 };
 
 } // namespace Consensus
diff --git a/src/consensus/tx_verify.cpp b/src/consensus/tx_verify.cpp
@@ -192,7 +192,7 @@ int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& i
     return nSigOps;
 }
 
-bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight, CAmountMap& fee_map, std::set<std::pair<uint256, COutPoint>>& setPeginsSpent, std::vector<CCheck*> *pvChecks, const bool cacheStore, bool fScriptChecks, const std::vector<std::pair<CScript, CScript>>& fedpegscripts)
+bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight, CAmountMap& fee_map, std::set<std::pair<uint256, COutPoint>>& setPeginsSpent, std::vector<CCheck*> *pvChecks, const bool cacheStore, bool fScriptChecks, const std::vector<std::pair<CScript, CScript>>& fedpegscripts, bool allow_any_fee)
 {
     // are the actual inputs available?
     if (!inputs.HaveInputs(tx)) {
@@ -245,7 +245,7 @@ bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state,
 
     if (g_con_elementsmode) {
         // Tally transaction fees
-        if (!HasValidFee(tx)) {
+        if (!HasValidFee(tx, allow_any_fee)) {
             return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-fee-outofrange");
         }
 
@@ -254,7 +254,7 @@ bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state,
             return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-in-ne-out", "value in != value out");
         }
         fee_map += GetFeeMap(tx);
-        if (!MoneyRange(fee_map)) {
+        if (allow_any_fee && !MoneyRange(fee_map)) {
             return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-block-total-fee-outofrange");
         }
     } else {
diff --git a/src/consensus/tx_verify.h b/src/consensus/tx_verify.h
@@ -28,7 +28,7 @@ namespace Consensus {
  * @param[out] fee_map Set to the transaction fee if successful.
  * Preconditions: tx.IsCoinBase() is false.
  */
-[[nodiscard] ]bool CheckTxInputs(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight, CAmountMap& fee_map, std::set<std::pair<uint256, COutPoint>>& setPeginsSpent, std::vector<CCheck*> *pvChecks, const bool cacheStore, bool fScriptChecks, const std::vector<std::pair<CScript, CScript>>& fedpegscripts);
+[[nodiscard] ]bool CheckTxInputs(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight, CAmountMap& fee_map, std::set<std::pair<uint256, COutPoint>>& setPeginsSpent, std::vector<CCheck*> *pvChecks, const bool cacheStore, bool fScriptChecks, const std::vector<std::pair<CScript, CScript>>& fedpegscripts, bool allow_any_fee);
 } // namespace Consensus
 
 /** Auxiliary functions for transaction validation (ideally should not be exposed) */
diff --git a/src/test/fuzz/coins_view.cpp b/src/test/fuzz/coins_view.cpp
@@ -252,7 +252,7 @@ FUZZ_TARGET_INIT(coins_view, initialize_coins_view)
                 }
                 std::vector<std::pair<CScript, CScript>> fedpegscripts; // ELEMENTS: we ought to populate this and have a more useful fuzztest
                 std::set<std::pair<uint256, COutPoint> > setPeginsSpent;
-                if (Consensus::CheckTxInputs(transaction, state, coins_view_cache, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, std::numeric_limits<int>::max()), tx_fee_map, setPeginsSpent, NULL, false, true, fedpegscripts)) {
+                if (Consensus::CheckTxInputs(transaction, state, coins_view_cache, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, std::numeric_limits<int>::max()), tx_fee_map, setPeginsSpent, NULL, false, true, fedpegscripts, false)) {
                     assert(MoneyRange(tx_fee_map));
                 }
             },
diff --git a/src/test/pegin_witness_tests.cpp b/src/test/pegin_witness_tests.cpp
@@ -123,15 +123,15 @@ BOOST_AUTO_TEST_CASE(witness_valid)
     CCoinsViewCache coins(&coinsDummy);
     // Get the latest block index to look up fedpegscripts
     // For these tests, should be genesis-block-hardcoded consensus.fedpegscript
-    BOOST_CHECK(Consensus::CheckTxInputs(tx, state, coins, 0, fee_map, setPeginsSpent, NULL, false, true, fedpegscripts));
+    BOOST_CHECK(Consensus::CheckTxInputs(tx, state, coins, 0, fee_map, setPeginsSpent, NULL, false, true, fedpegscripts, false));
     BOOST_CHECK(setPeginsSpent.size() == 1);
     setPeginsSpent.clear();
 
     // Strip pegin_witness
     CMutableTransaction mtxn(tx);
     mtxn.witness.vtxinwit[0].m_pegin_witness.SetNull();
     CTransaction tx2(mtxn);
-    BOOST_CHECK(!Consensus::CheckTxInputs(tx2, state, coins, 0, fee_map, setPeginsSpent, NULL, false, true, fedpegscripts));
+    BOOST_CHECK(!Consensus::CheckTxInputs(tx2, state, coins, 0, fee_map, setPeginsSpent, NULL, false, true, fedpegscripts, false));
     BOOST_CHECK(setPeginsSpent.empty());
 
     // Invalidate peg-in (and spending) authorization by pegin marker.
@@ -140,7 +140,7 @@ BOOST_AUTO_TEST_CASE(witness_valid)
     CMutableTransaction mtxn2(tx);
     mtxn2.vin[0].m_is_pegin = false;
     CTransaction tx3(mtxn2);
-    BOOST_CHECK(!Consensus::CheckTxInputs(tx3, state, coins, 0, fee_map, setPeginsSpent, NULL, false, true, fedpegscripts));
+    BOOST_CHECK(!Consensus::CheckTxInputs(tx3, state, coins, 0, fee_map, setPeginsSpent, NULL, false, true, fedpegscripts, false));
     BOOST_CHECK(setPeginsSpent.empty());
 
 
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
@@ -895,7 +895,7 @@ void CTxMemPool::check(const CBlockIndex* active_chain_tip, const CCoinsViewCach
         const auto& fedpegscripts = GetValidFedpegScripts(active_chain_tip, Params().GetConsensus(), true /* nextblock_validation */);
         bool cacheStore = true;
         bool fScriptChecks = true;
-        assert(Consensus::CheckTxInputs(tx, dummy_state, mempoolDuplicate, spendheight, fee_map, setPeginsSpent, nullptr, cacheStore, fScriptChecks, fedpegscripts));
+        assert(Consensus::CheckTxInputs(tx, dummy_state, mempoolDuplicate, spendheight, fee_map, setPeginsSpent, nullptr, cacheStore, fScriptChecks, fedpegscripts, Params().GetConsensus().allow_any_fee));
         for (const auto& input: tx.vin) mempoolDuplicate.SpendCoin(input.prevout);
         AddCoins(mempoolDuplicate, tx, std::numeric_limits<int>::max());
     }
diff --git a/src/validation.cpp b/src/validation.cpp
@@ -855,10 +855,12 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
 
     // The mempool holds txs for the next block, so pass height+1 to CheckTxInputs
     CAmountMap fee_map;
-    if (!Consensus::CheckTxInputs(tx, state, m_view, m_active_chainstate.m_chain.Height() + 1, fee_map, setPeginsSpent, NULL, true, true, fedpegscripts)) {
+    if (!Consensus::CheckTxInputs(tx, state, m_view, m_active_chainstate.m_chain.Height() + 1, fee_map, setPeginsSpent, NULL, true, true, fedpegscripts, Params().GetConsensus().allow_any_fee)) {
         return false; // state filled in by CheckTxInputs
     }
 
+    LogPrintf("mand coin: %u\n", Params().GetConsensus().allow_any_fee);
+
     // ELEMENTS: extra policy check for consistency between issuances and their rangeproof
     if (fRequireStandard) {
         for (unsigned i = 0; i < std::min(tx.witness.vtxinwit.size(), tx.vin.size()); i++) {
@@ -2350,7 +2352,7 @@ bool CChainState::ConnectBlock(const CBlock& block, BlockValidationState& state,
             TxValidationState tx_state;
             if (!Consensus::CheckTxInputs(tx, tx_state, view, pindex->nHeight, fee_map,
                         setPeginsSpent == NULL ? setPeginsSpentDummy : *setPeginsSpent,
-                        g_parallel_script_checks ? &vChecks : NULL, fCacheResults, fScriptChecks, fedpegscripts)) {
+                        g_parallel_script_checks ? &vChecks : NULL, fCacheResults, fScriptChecks, fedpegscripts, Params().GetConsensus().allow_any_fee)) {
                 // Any transaction validation failure in ConnectBlock is a block consensus failure
                 state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                         tx_state.GetRejectReason(), tx_state.GetDebugMessage());
diff --git a/src/wallet/rpc/transactions.cpp b/src/wallet/rpc/transactions.cpp
@@ -823,7 +823,7 @@ RPCHelpMan gettransaction()
     CAmountMap nCredit = CachedTxGetCredit(*pwallet, wtx, filter);
     CAmountMap nDebit = CachedTxGetDebit(*pwallet, wtx, filter);
     CAmountMap nNet = nCredit - nDebit;
-    CHECK_NONFATAL(HasValidFee(*wtx.tx));
+    CHECK_NONFATAL(HasValidFee(*wtx.tx,Params().GetConsensus().allow_any_fee));
     CAmountMap nFee = CachedTxIsFromMe(*pwallet, wtx, filter) ? CAmountMap() - GetFeeMap(*wtx.tx) : CAmountMap();
     if (!g_con_elementsmode) {
         CAmount total_out = 0;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
@@ -3024,7 +3024,7 @@ std::shared_ptr<CWallet> CWallet::Create(WalletContext& context, const std::stri
 
     if (args.IsArgSet("-mintxfee")) {
         std::optional<CAmount> min_tx_fee = ParseMoney(args.GetArg("-mintxfee", ""));
-        if (!min_tx_fee || min_tx_fee.value() == 0) {
+        if (!min_tx_fee || (!Params().GetConsensus().allow_any_fee && min_tx_fee.value() == 0)) {
             error = AmountErrMsg("mintxfee", args.GetArg("-mintxfee", ""));
             return nullptr;
         } else if (min_tx_fee.value() > HIGH_TX_FEE_PER_KB) {
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
@@ -356,6 +356,7 @@
     'feature_coinstatsindex.py --legacy-wallet',
     'feature_coinstatsindex.py --descriptors',
     'wallet_orphanedreward.py',
+    'wallet_send_zero_fee.py',
     'wallet_timelock.py',
     'p2p_node_network_limited.py',
     'p2p_permissions.py',
diff --git a/test/functional/wallet_send_zero_fee.py b/test/functional/wallet_send_zero_fee.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+# Copyright (c) 2017-2020 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+from decimal import Decimal
+
+from test_framework.blocktools import COINBASE_MATURITY
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+)
+
+class WalletTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.setup_clean_chain = True
+        self.num_nodes = 3
+        self.extra_args = [[
+            "-blindedaddresses=1",
+            "-initialfreecoins=2100000000000000",
+            "-con_blocksubsidy=0",
+            "-con_connect_genesis_outputs=1",
+            "-txindex=1",
+            "-minrelaytxfee=0",
+            "-blockmintxfee=0",
+            "-mintxfee=0",
+            "-con_allow_any_fee=1"
+        ]] * self.num_nodes
+        self.extra_args[0].append("-anyonecanspendaremine=1")
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def run_test(self):
+        self.generate(self.nodes[0], COINBASE_MATURITY + 1)
+        self.sync_all()
+
+        self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 10)
+        self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 20)
+        self.generate(self.nodes[0], 1)
+        assert_equal(self.nodes[0].getblockchaininfo()["blocks"], 102)
+        assert_equal(self.nodes[0].getbalance(), {'bitcoin': Decimal('20999969.99900900')})
+        assert_equal(self.nodes[1].getbalance(), {'bitcoin': Decimal('10.00000000')})
+        assert_equal(self.nodes[2].getbalance(), {'bitcoin': Decimal('20.00000000')})
+
+        addr = self.nodes[1].getnewaddress()
+        txid = self.nodes[0].sendtoaddress(addr, 1, None, None, None, None, None, None, None, None, None, 0, False)
+        tx = self.nodes[0].gettransaction(txid)
+        assert_equal(tx["fee"]["bitcoin"], 0)
+        hex = self.nodes[0].getrawtransaction(txid)
+        self.generate(self.nodes[0], 1)
+        assert_equal(self.nodes[0].getblockchaininfo()["blocks"], 103)
+
+        decoded = self.nodes[0].decoderawtransaction(hex)
+        bitcoin = "b2e15d0d7a0c94e4e2ce0fe6e8691b9e451377f6e46e8045a86f7c4b5d4f0f23"
+        assert_equal(decoded["fee"][bitcoin], 0)
+        assert_equal(self.nodes[0].getbalance(), {'bitcoin': Decimal('20999968.99900900')})
+        assert_equal(self.nodes[1].getbalance(), {'bitcoin': Decimal('11.00000000')})
+        assert_equal(self.nodes[2].getbalance(), {'bitcoin': Decimal('20.00000000')})
+
+if __name__ == '__main__':
+    WalletTest().main()

Original file line number	Diff line number	Diff line change
`@@ -192,7 +192,7 @@ int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& i`
`192`	`192`	`return nSigOps;`
`193`	`193`	`}`
`194`	`194`
`195`		`-bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight, CAmountMap& fee_map, std::set<std::pair<uint256, COutPoint>>& setPeginsSpent, std::vector<CCheck> pvChecks, const bool cacheStore, bool fScriptChecks, const std::vector<std::pair<CScript, CScript>>& fedpegscripts)`
	`195`	`+bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight, CAmountMap& fee_map, std::set<std::pair<uint256, COutPoint>>& setPeginsSpent, std::vector<CCheck> pvChecks, const bool cacheStore, bool fScriptChecks, const std::vector<std::pair<CScript, CScript>>& fedpegscripts, bool allow_any_fee)`
`196`	`196`	`{`
`197`	`197`	`// are the actual inputs available?`
`198`	`198`	`if (!inputs.HaveInputs(tx)) {`
`@@ -245,7 +245,7 @@ bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state,`
`245`	`245`
`246`	`246`	`if (g_con_elementsmode) {`
`247`	`247`	`// Tally transaction fees`
`248`		`- if (!HasValidFee(tx)) {`
	`248`	`+ if (!HasValidFee(tx, allow_any_fee)) {`
`249`	`249`	`return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-fee-outofrange");`
`250`	`250`	`}`
`251`	`251`
`@@ -254,7 +254,7 @@ bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state,`
`254`	`254`	`return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-in-ne-out", "value in != value out");`
`255`	`255`	`}`
`256`	`256`	`fee_map += GetFeeMap(tx);`
`257`		`- if (!MoneyRange(fee_map)) {`
	`257`	`+ if (allow_any_fee && !MoneyRange(fee_map)) {`
`258`	`258`	`return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-block-total-fee-outofrange");`
`259`	`259`	`}`
`260`	`260`	`} else {`
Original file line number	Diff line number	Diff line change
`@@ -252,7 +252,7 @@ FUZZ_TARGET_INIT(coins_view, initialize_coins_view)`
`252`	`252`	`}`
`253`	`253`	`std::vector<std::pair<CScript, CScript>> fedpegscripts; // ELEMENTS: we ought to populate this and have a more useful fuzztest`
`254`	`254`	`std::set<std::pair<uint256, COutPoint> > setPeginsSpent;`
`255`		`- if (Consensus::CheckTxInputs(transaction, state, coins_view_cache, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, std::numeric_limits<int>::max()), tx_fee_map, setPeginsSpent, NULL, false, true, fedpegscripts)) {`
	`255`	`+ if (Consensus::CheckTxInputs(transaction, state, coins_view_cache, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, std::numeric_limits<int>::max()), tx_fee_map, setPeginsSpent, NULL, false, true, fedpegscripts, false)) {`
`256`	`256`	`assert(MoneyRange(tx_fee_map));`
`257`	`257`	`}`
`258`	`258`	`},`
Original file line number	Diff line number	Diff line change
`@@ -895,7 +895,7 @@ void CTxMemPool::check(const CBlockIndex* active_chain_tip, const CCoinsViewCach`
`895`	`895`	`const auto& fedpegscripts = GetValidFedpegScripts(active_chain_tip, Params().GetConsensus(), true /* nextblock_validation */);`
`896`	`896`	`bool cacheStore = true;`
`897`	`897`	`bool fScriptChecks = true;`
`898`		`- assert(Consensus::CheckTxInputs(tx, dummy_state, mempoolDuplicate, spendheight, fee_map, setPeginsSpent, nullptr, cacheStore, fScriptChecks, fedpegscripts));`
	`898`	`+ assert(Consensus::CheckTxInputs(tx, dummy_state, mempoolDuplicate, spendheight, fee_map, setPeginsSpent, nullptr, cacheStore, fScriptChecks, fedpegscripts, Params().GetConsensus().allow_any_fee));`
`899`	`899`	`for (const auto& input: tx.vin) mempoolDuplicate.SpendCoin(input.prevout);`
`900`	`900`	`AddCoins(mempoolDuplicate, tx, std::numeric_limits<int>::max());`
`901`	`901`	`}`