Do not error when user is typing send amount

crates/ln-dlc-node/Cargo.toml

@@ -42,6 +42,7 @@ secp256k1-zkp = { version = "0.7.0", features = ["global-context"] }
 serde = "1.0.147"
 serde_with = "3.1.0"
 sha2 = "0.10"
+thiserror = "1"
 time = "0.3"
 tokio = { version = "1", default-features = false, features = ["io-util", "macros", "rt", "rt-multi-thread", "sync", "time", "tracing"] }
 tracing = "0.1.37"

crates/ln-dlc-node/src/lib.rs

@@ -46,6 +46,7 @@ pub use ln::DlcChannelDetails;
 pub use ln::EventHandlerTrait;
 pub use ln::EventSender;
 pub use on_chain_wallet::ConfirmationStatus;
+pub use on_chain_wallet::EstimateFeeError;
 pub use on_chain_wallet::TransactionDetails;
 
 #[cfg(test)]

crates/ln-dlc-node/src/node/mod.rs

@@ -29,7 +29,6 @@ use bitcoin::address::NetworkUnchecked;
 use bitcoin::secp256k1::PublicKey;
 use bitcoin::secp256k1::XOnlyPublicKey;
 use bitcoin::Address;
-use bitcoin::Amount;
 use bitcoin::Network;
 use bitcoin::Txid;
 use dlc_messages::message_handler::MessageHandler as DlcMessageHandler;
@@ -538,19 +537,6 @@ impl<D: BdkStorage, S: TenTenOneStorage + 'static, N: Storage + Sync + Send + 's
         )
     }
 
-    /// Estimate the fee for sending the given `amount_sats` to the given `address` on-chain with
-    /// the given `fee`.
-    pub fn estimate_fee(
-        &self,
-        address: Address<NetworkUnchecked>,
-        amount_sats: u64,
-        fee: ConfirmationTarget,
-    ) -> Result<Amount> {
-        let address = address.require_network(self.network)?;
-
-        self.wallet.estimate_fee(&address, amount_sats, fee)
-    }
-
     /// Send the given `amount_sats` sats to the given unchecked, on-chain `address`.
     pub async fn send_to_address(
         &self,

crates/ln-dlc-node/src/node/wallet.rs

@@ -1,6 +1,7 @@
 use crate::bitcoin_conversion::to_secp_sk_30;
 use crate::node::Node;
 use crate::node::Storage;
+use crate::on_chain_wallet;
 use crate::on_chain_wallet::BdkStorage;
 use crate::on_chain_wallet::OnChainWallet;
 use crate::on_chain_wallet::TransactionDetails;
@@ -10,9 +11,11 @@ use anyhow::Result;
 use bdk_esplora::EsploraAsyncExt;
 use bitcoin::secp256k1::SecretKey;
 use bitcoin::Address;
+use bitcoin::Amount;
 use bitcoin::OutPoint;
 use bitcoin::ScriptBuf;
 use bitcoin::TxOut;
+use lightning::chain::chaininterface::ConfirmationTarget;
 use std::sync::Arc;
 use tokio::task::spawn_blocking;
 
@@ -60,6 +63,17 @@ impl<D: BdkStorage, S: TenTenOneStorage, N: Storage + Send + Sync + 'static> Nod
         self.wallet.is_mine(script_pubkey)
     }
 
+    /// Estimate the fee for sending the given `amount_sats` to the given `address` on-chain with
+    /// the given `fee`.
+    pub fn estimate_fee(
+        &self,
+        address: Address,
+        amount_sats: u64,
+        fee: ConfirmationTarget,
+    ) -> Result<Amount, on_chain_wallet::EstimateFeeError> {
+        self.wallet.estimate_fee(&address, amount_sats, fee)
+    }
+
     /// Sync the state of the on-chain wallet against the blockchain.
     pub async fn sync_on_chain_wallet(&self) -> Result<()> {
         let client = &self.blockchain.esplora_client_async;

crates/ln-dlc-node/src/on_chain_wallet.rs

@@ -13,6 +13,7 @@ use bdk::chain::Append;
 use bdk::chain::ChainPosition;
 use bdk::chain::PersistBackend;
 use bdk::psbt::PsbtUtils;
+use bdk::wallet::IsDust;
 use bdk::KeychainKind;
 use bdk::LocalOutput;
 use bdk::SignOptions;
@@ -377,7 +378,11 @@ where
         recipient: &Address,
         amount_sat_or_drain: u64,
         confirmation_target: ConfirmationTarget,
-    ) -> Result<Amount> {
+    ) -> Result<Amount, EstimateFeeError> {
+        if amount_sat_or_drain.is_dust(&recipient.script_pubkey()) {
+            return Err(EstimateFeeError::SendAmountBelowDust);
+        }
+
         let psbt = self.build_psbt(
             recipient,
             amount_sat_or_drain,
@@ -449,6 +454,14 @@ impl ConfirmationStatus {
     }
 }
 
+#[derive(thiserror::Error, Debug)]
+pub enum EstimateFeeError {
+    #[error("Cannot estimate fee for output below dust")]
+    SendAmountBelowDust,
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
 pub trait BdkStorage: PersistBackend<bdk::wallet::ChangeSet> + Send + Sync + 'static {}
 
 #[derive(Default)]

mobile/native/src/api.rs

@@ -674,7 +674,11 @@ pub fn calculate_all_fees_for_on_chain(address: String, amount: u64) -> Result<V
             let fee_rate = fee_rate(confirmation_target);
 
             let fee_config = Fee::Priority(confirmation_target);
-            let absolute_fee = ln_dlc::estimate_payment_fee(amount, &address, fee_config).await?;
+            let absolute_fee =
+                match ln_dlc::estimate_payment_fee(amount, &address, fee_config).await? {
+                    Some(fee) => fee,
+                    None => Amount::ZERO,
+                };
 
             fees.push(FeeEstimation {
                 sats_per_vbyte: fee_rate.ceil() as u64,

mobile/native/src/ln_dlc/mod.rs

@@ -979,18 +979,29 @@ pub fn estimated_funding_tx_fee() -> Result<Amount> {
     Ok(fee)
 }
 
-pub async fn estimate_payment_fee(amount: u64, address: &str, fee: Fee) -> Result<Amount> {
-    let address = address.parse()?;
+pub async fn estimate_payment_fee(amount: u64, address: &str, fee: Fee) -> Result<Option<Amount>> {
+    let address: Address<NetworkUnchecked> = address.parse().context("Failed to parse address")?;
+    // This is safe to do because we are only using this address to estimate a fee.
+    let address = address.assume_checked();
 
     let fee = match fee {
-        Fee::Priority(target) => state::get_node()
-            .inner
-            .estimate_fee(address, amount, target.into())?
-            .to_sat(),
-        Fee::FeeRate { sats } => sats,
+        Fee::Priority(target) => {
+            match state::get_node()
+                .inner
+                .estimate_fee(address, amount, target.into())
+            {
+                Ok(fee) => Some(fee),
+                // It's not sensible to calculate the fee for an amount below dust.
+                Err(ln_dlc_node::EstimateFeeError::SendAmountBelowDust) => None,
+                Err(e) => {
+                    bail!("Failed to estimate payment fee: {e:#}")
+                }
+            }
+        }
+        Fee::FeeRate { sats } => Some(Amount::from_sat(sats)),
     };
 
-    Ok(Amount::from_sat(fee))
+    Ok(fee)
 }
 
 pub async fn trade(