What the developer wrote
Authored by glozow
test fixup for incremental feerate
Clarify that the purpose of some parameters are to ensure identical
transactions are not created. Also, strengthen the test to catch these cases.
What changed, and why it matters
This is a test-only change in Bitcoin Core. It clarifies comments and strengthens a functional test for Replace-By-Fee (RBF) behavior when the incremental relay feerate is set to zero. No production code, consensus rules, or network behavior were modified.
No security action needed. This is a routine test improvement.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The commit modifies test/functional/feature_rbf.py. It removes an unused import, adds explanatory comments about why different transaction versions and target vsizes are used, and adds a branch to verify that when incremental relay feerate is zero, a replacement still requires a higher absolute fee rate (so a smaller transaction at the same absolute fee succeeds, while an identically-sized one fails). This is purely a test hardening and documentation change.
Changed components
test/functional/feature_rbf.pyInspect captured patch +14 / −11
diff --git a/test/functional/feature_rbf.py b/test/functional/feature_rbf.py
index 86fe2f5b..6922b5e0 100755
--- a/test/functional/feature_rbf.py
+++ b/test/functional/feature_rbf.py
@@ -13,7 +13,6 @@ from test_framework.messages import (
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
assert_equal,
- assert_greater_than,
assert_greater_than_or_equal,
assert_raises_rpc_error,
get_fee,
@@ -603,23 +602,27 @@ class ReplaceByFeeTest(BitcoinTestFramework):
low_feerate = min_relay_feerate * 2
confirmed_utxo = self.wallet.get_utxo(confirmed_only=True)
- replacee_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee_rate=low_feerate, target_vsize=5000)
+ # Use different versions to avoid creating an identical transaction when failed_replacement_tx is created.
+ # Use a target vsize that is small, but something larger than the minimum so that we can create a transaction that is 1vB smaller later.
+ replacee_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee_rate=low_feerate, version=3, target_vsize=200)
node.sendrawtransaction(replacee_tx['hex'])
- replacement_placeholder_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo)
+ replacement_placeholder_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, target_vsize=200)
replacement_expected_size = replacement_placeholder_tx['tx'].get_vsize()
replacement_required_fee = get_fee(replacement_expected_size, incremental_setting_decimal) + replacee_tx['fee']
- # Should always be required to pay additional fees
- if incremental_setting > 0:
- assert_greater_than(replacement_required_fee, replacee_tx['fee'])
-
- # 1 satoshi shy of the required fee
- failed_replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee - Decimal("0.00000001"))
+ # Show that replacement fails when paying 1 satoshi shy of the required fee
+ failed_replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee - Decimal("0.00000001"), version=2, target_vsize=200)
assert_raises_rpc_error(-26, "insufficient fee", node.sendrawtransaction, failed_replacement_tx['hex'])
+ replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee, version=2, target_vsize=200)
- replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee)
- node.sendrawtransaction(replacement_tx['hex'])
+ if incremental_setting == 0:
+ # When incremental relay feerate is 0, additional fees are not required, but higher feerate is still required.
+ assert_raises_rpc_error(-26, "insufficient fee", node.sendrawtransaction, replacement_tx['hex'])
+ replacement_tx_smaller = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee, version=2, target_vsize=199)
+ node.sendrawtransaction(replacement_tx_smaller['hex'])
+ else:
+ node.sendrawtransaction(replacement_tx['hex'])
def test_fullrbf(self):
# BIP125 signaling is not respected
Why this scored 14/100
Community notes
Notes can correct, qualify, or add evidence to the AI analysis. Every note shown here has been validated by a human moderator.
The AI analysis stands alone for now. Submit a note if you can add evidence or important context.