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-rwxr-xr-xtest/functional/rpc_fundrawtransaction.py57
1 files changed, 57 insertions, 0 deletions
diff --git a/test/functional/rpc_fundrawtransaction.py b/test/functional/rpc_fundrawtransaction.py
index fa98c44152..2524eaa7a5 100755
--- a/test/functional/rpc_fundrawtransaction.py
+++ b/test/functional/rpc_fundrawtransaction.py
@@ -99,6 +99,7 @@ class RawTransactionsTest(BitcoinTestFramework):
self.test_subtract_fee_with_presets()
self.test_transaction_too_large()
self.test_include_unsafe()
+ self.test_22670()
def test_change_position(self):
"""Ensure setting changePosition in fundraw with an exact match is handled properly."""
@@ -969,6 +970,62 @@ class RawTransactionsTest(BitcoinTestFramework):
signedtx = wallet.signrawtransactionwithwallet(fundedtx['hex'])
wallet.sendrawtransaction(signedtx['hex'])
+ def test_22670(self):
+ # In issue #22670, it was observed that ApproximateBestSubset may
+ # choose enough value to cover the target amount but not enough to cover the transaction fees.
+ # This leads to a transaction whose actual transaction feerate is lower than expected.
+ # However at normal feerates, the difference between the effective value and the real value
+ # that this bug is not detected because the transaction fee must be at least 0.01 BTC (the minimum change value).
+ # Otherwise the targeted minimum change value will be enough to cover the transaction fees that were not
+ # being accounted for. So the minimum relay fee is set to 0.1 BTC/kvB in this test.
+ self.log.info("Test issue 22670 ApproximateBestSubset bug")
+ # Make sure the default wallet will not be loaded when restarted with a high minrelaytxfee
+ self.nodes[0].unloadwallet(self.default_wallet_name, False)
+ feerate = Decimal("0.1")
+ self.restart_node(0, [f"-minrelaytxfee={feerate}", "-discardfee=0"]) # Set high minrelayfee, set discardfee to 0 for easier calculation
+
+ self.nodes[0].loadwallet(self.default_wallet_name, True)
+ funds = self.nodes[0].get_wallet_rpc(self.default_wallet_name)
+ self.nodes[0].createwallet(wallet_name="tester")
+ tester = self.nodes[0].get_wallet_rpc("tester")
+
+ # Because this test is specifically for ApproximateBestSubset, the target value must be greater
+ # than any single input available, and require more than 1 input. So we make 3 outputs
+ for i in range(0, 3):
+ funds.sendtoaddress(tester.getnewaddress(address_type="bech32"), 1)
+ self.nodes[0].generate(1)
+
+ # Create transactions in order to calculate fees for the target bounds that can trigger this bug
+ change_tx = tester.fundrawtransaction(tester.createrawtransaction([], [{funds.getnewaddress(): 1.5}]))
+ tx = tester.createrawtransaction([], [{funds.getnewaddress(): 2}])
+ no_change_tx = tester.fundrawtransaction(tx, {"subtractFeeFromOutputs": [0]})
+
+ overhead_fees = feerate * len(tx) / 2 / 1000
+ cost_of_change = change_tx["fee"] - no_change_tx["fee"]
+ fees = no_change_tx["fee"]
+ assert_greater_than(fees, 0.01)
+
+ def do_fund_send(target):
+ create_tx = tester.createrawtransaction([], [{funds.getnewaddress(): lower_bound}])
+ funded_tx = tester.fundrawtransaction(create_tx)
+ signed_tx = tester.signrawtransactionwithwallet(funded_tx["hex"])
+ assert signed_tx["complete"]
+ decoded_tx = tester.decoderawtransaction(signed_tx["hex"])
+ assert_equal(len(decoded_tx["vin"]), 3)
+ assert tester.testmempoolaccept([signed_tx["hex"]])[0]["allowed"]
+
+ # We want to choose more value than is available in 2 inputs when considering the fee,
+ # but not enough to need 3 inputs when not considering the fee.
+ # So the target value must be at least 2.00000001 - fee.
+ lower_bound = Decimal("2.00000001") - fees
+ # The target value must be at most 2 - cost_of_change - not_input_fees - min_change (these are all
+ # included in the target before ApproximateBestSubset).
+ upper_bound = Decimal("2.0") - cost_of_change - overhead_fees - Decimal("0.01")
+ assert_greater_than_or_equal(upper_bound, lower_bound)
+ do_fund_send(lower_bound)
+ do_fund_send(upper_bound)
+
+ self.restart_node(0)
if __name__ == '__main__':
RawTransactionsTest().main()