Add checks to max_giveable amount.

We need to check two things:
- balance to be higher than dust amount (546).
- balance to be higher than min-relay fee.

Additionally, the tx_builder might fail if not enough funds are in the wallet to pay for the overall transaction fees.
This commit is contained in:
Philipp Hoenisch 2021-05-12 14:36:06 +10:00
parent 6bc21a9318
commit 7fc5a47619
No known key found for this signature in database
GPG Key ID: E5F8E74C672BC666

View File

@ -30,6 +30,7 @@ const SLED_TREE_NAME: &str = "default_tree";
/// amount for tx fees.
const MAX_RELATIVE_TX_FEE: Decimal = dec!(0.03);
const MAX_ABSOLUTE_TX_FEE: Decimal = dec!(100_000);
const DUST_AMOUNT: u64 = 546;
pub struct Wallet<B = ElectrumBlockchain, D = bdk::sled::Tree, C = Client> {
client: Arc<Mutex<C>>,
@ -316,7 +317,17 @@ where
/// transaction confirmed.
pub async fn max_giveable(&self, locking_script_size: usize) -> Result<Amount> {
let wallet = self.wallet.lock().await;
let balance = wallet.get_balance()?;
if balance < DUST_AMOUNT {
return Ok(Amount::ZERO);
}
let client = self.client.lock().await;
let min_relay_fee = client.min_relay_fee()?.as_sat();
if balance < min_relay_fee {
return Ok(Amount::ZERO);
}
let fee_rate = client.estimate_feerate(self.target_block)?;
let mut tx_builder = wallet.build_tx();
@ -325,11 +336,16 @@ where
tx_builder.set_single_recipient(dummy_script);
tx_builder.drain_wallet();
tx_builder.fee_rate(fee_rate);
let (_, details) = tx_builder.finish().context("Failed to build transaction")?;
let max_giveable = details.sent - details.fees;
Ok(Amount::from_sat(max_giveable))
let response = tx_builder.finish();
match response {
Ok((_, details)) => {
let max_giveable = details.sent - details.fees;
Ok(Amount::from_sat(max_giveable))
}
Err(bdk::Error::InsufficientFunds { .. }) => Ok(Amount::ZERO),
Err(e) => bail!("Failed to build transaction. {:#}", e),
}
}
/// Estimate total tx fee for a pre-defined target block based on the
@ -758,6 +774,7 @@ impl fmt::Display for ScriptStatus {
#[cfg(test)]
mod tests {
use super::*;
use crate::bitcoin::TxLock;
use proptest::prelude::*;
#[test]
@ -945,4 +962,46 @@ mod tests {
assert!(estimate_fee(weight, amount, fee_rate, relay_fee).is_err());
}
}
struct StaticFeeRate {
min_relay_fee: u64,
}
impl EstimateFeeRate for StaticFeeRate {
fn estimate_feerate(&self, _target_block: usize) -> Result<FeeRate> {
Ok(FeeRate::default_min_relay_fee())
}
fn min_relay_fee(&self) -> Result<bitcoin::Amount> {
Ok(bitcoin::Amount::from_sat(self.min_relay_fee))
}
}
#[tokio::test]
async fn given_no_balance_returns_amount_0() {
let wallet = Wallet::new_funded(0, StaticFeeRate { min_relay_fee: 1 });
let amount = wallet.max_giveable(TxLock::script_size()).await.unwrap();
assert_eq!(amount, Amount::ZERO);
}
#[tokio::test]
async fn given_balance_below_min_relay_fee_returns_amount_0() {
let wallet = Wallet::new_funded(1000, StaticFeeRate {
min_relay_fee: 1001,
});
let amount = wallet.max_giveable(TxLock::script_size()).await.unwrap();
assert_eq!(amount, Amount::ZERO);
}
#[tokio::test]
async fn given_balance_above_relay_fee_returns_amount_greater_0() {
let wallet = Wallet::new_funded(10_000, StaticFeeRate {
min_relay_fee: 1000,
});
let amount = wallet.max_giveable(TxLock::script_size()).await.unwrap();
assert!(amount.as_sat() > 0);
}
}