chore: allow calling settle and cancel multiple times

Cargo.toml

@@ -24,7 +24,7 @@ rcgen = { version = "0.13.1", features = ["x509-parser"] }
 tokio = { version = "1.40.0", features = ["macros", "rt-multi-thread", "sync"] }
 tonic = { version = "0.12.3", features = ["prost", "tls", "gzip", "zstd"] }
 serde = { version = "1.0.210", features = ["derive"] }
-serde_json = { version = "1.0.128", features = ["preserve_order"] }
+serde_json = { version = "1.0.129", features = ["preserve_order"] }
 lightning-invoice = { version = "0.32.0", features = ["std"] }
 chrono = { version = "0.4.38", features = ["serde"] }
 bitcoin = { version = "0.32.3", features = ["rand-std"] }
@@ -34,7 +34,7 @@ hex = "0.4.3"
 tokio-util = "0.7.12"
 
 [build-dependencies]
-built = { version = "0.7.4", features = ["git2"] }
+built = { version = "0.7.5", features = ["git2"] }
 tonic-build = "0.12.3"
 
 [dev-dependencies]

src/database/model.rs

@@ -149,7 +149,7 @@ impl InvoiceState {
     }
 
     pub fn validate_transition(&self, new_state: InvoiceState) -> Result<(), StateTransitionError> {
-        if self.is_final() {
+        if self.is_final() && *self != new_state {
             return Err(StateTransitionError::IsFinal(*self));
         }
 
@@ -320,6 +320,16 @@ mod test {
         );
     }
 
+    #[test]
+    fn invoice_state_validate_transition_final_same_state() {
+        assert!(InvoiceState::Paid
+            .validate_transition(InvoiceState::Paid)
+            .is_ok());
+        assert!(InvoiceState::Cancelled
+            .validate_transition(InvoiceState::Cancelled)
+            .is_ok());
+    }
+
     #[test]
     fn invoice_state_validate_transition_invalid() {
         assert_eq!(

src/settler.rs

@@ -1,5 +1,5 @@
 use crate::database::helpers::invoice_helper::InvoiceHelper;
-use crate::database::model::{Invoice, InvoiceState};
+use crate::database::model::{HoldInvoice, Invoice, InvoiceState};
 use crate::hooks::{FailureMessage, HtlcCallbackResponse};
 use anyhow::Result;
 use log::{info, trace, warn};
@@ -147,6 +147,10 @@ where
         payment_hash: &Vec<u8>,
         payment_preimage: &Vec<u8>,
     ) -> Result<()> {
+        if self.get_invoice(payment_hash)?.invoice.state == InvoiceState::Paid.to_string() {
+            return Ok(());
+        }
+
         let htlcs = match self.pending_htlcs.lock().await.remove(payment_hash) {
             Some(res) => res,
             None => {
@@ -321,14 +325,7 @@ where
         payment_hash: &[u8],
         state: InvoiceState,
     ) -> Result<(i64, String)> {
-        let invoice = match self.invoice_helper.get_by_payment_hash(payment_hash) {
-            Ok(opt) => match opt {
-                Some(invoice) => invoice,
-                None => return Err(SettleError::InvoiceNotFound.into()),
-            },
-            Err(err) => return Err(SettleError::DatabaseFetchError(err).into()),
-        };
-
+        let invoice = self.get_invoice(payment_hash)?;
         let current_state = InvoiceState::try_from(&invoice.invoice.state)?;
 
         if let Err(err) =
@@ -347,4 +344,14 @@ where
 
         Ok((invoice.invoice.id, invoice.invoice.bolt11))
     }
+
+    fn get_invoice(&self, payment_hash: &[u8]) -> Result<HoldInvoice> {
+        match self.invoice_helper.get_by_payment_hash(payment_hash) {
+            Ok(opt) => match opt {
+                Some(invoice) => Ok(invoice),
+                None => Err(SettleError::InvoiceNotFound.into()),
+            },
+            Err(err) => Err(SettleError::DatabaseFetchError(err).into()),
+        }
+    }
 }

tests-regtest/hold/regtest_rpc.py

@@ -89,6 +89,9 @@ def test_settle(self) -> None:
         assert len(htlcs) == 1
         assert htlcs[0]["state"] == "paid"
 
+        # Settling again should not error
+        assert lightning("settleholdinvoice", preimage) == {}
+
     def test_cancel(self) -> None:
         (_, payment_hash) = new_preimage()
         invoice = lightning("holdinvoice", payment_hash, "1000")["bolt11"]
@@ -115,3 +118,6 @@ def test_cancel(self) -> None:
         htlcs = data["htlcs"]
         assert len(htlcs) == 1
         assert htlcs[0]["state"] == "cancelled"
+
+        # Cancelling again should not error
+        assert lightning("cancelholdinvoice", payment_hash) == {}