wallet: log when saving already paid invoice

(maybe it should not be allowed?)

electrum/wallet.py

@@ -614,6 +614,8 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         if invoice_type == PR_TYPE_LN:
             key = invoice['rhash']
         elif invoice_type == PR_TYPE_ONCHAIN:
+            if self.is_onchain_invoice_paid(invoice):
+                self.logger.info("saving invoice... but it is already paid!")
             key = bh2u(sha256(repr(invoice))[0:16])
             invoice['id'] = key
             outputs = invoice['outputs']  # type: List[PartialTxOutput]
@@ -643,7 +645,7 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         item = copy.copy(self.invoices[key])
         request_type = item.get('type')
         if request_type == PR_TYPE_ONCHAIN:
-            item['status'] = PR_PAID if self._is_onchain_invoice_paid(item)[0] else PR_UNPAID
+            item['status'] = PR_PAID if self.is_onchain_invoice_paid(item) else PR_UNPAID
         elif self.lnworker and request_type == PR_TYPE_LN:
             item['status'] = self.lnworker.get_payment_status(bfh(item['rhash']))
         else:
@@ -666,7 +668,7 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
                 for txout in outputs:
                     self._invoices_from_scriptpubkey_map[txout.scriptpubkey].add(invoice_key)
 
-    def _is_onchain_invoice_paid(self, invoice) -> Tuple[bool, Sequence[str]]:
+    def _is_onchain_invoice_paid(self, invoice: dict) -> Tuple[bool, Sequence[str]]:
         """Returns whether on-chain invoice is satisfied, and list of relevant TXIDs."""
         assert invoice.get('type') == PR_TYPE_ONCHAIN
         invoice_amounts = defaultdict(int)  # type: Dict[bytes, int]  # scriptpubkey -> value_sats
@@ -687,6 +689,9 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
                     return False, []
         return True, relevant_txs
 
+    def is_onchain_invoice_paid(self, invoice: dict) -> bool:
+        return self._is_onchain_invoice_paid(invoice)[0]
+
     def _maybe_set_tx_label_based_on_invoices(self, tx: Transaction) -> bool:
         tx_hash = tx.txid()
         with self.transaction_lock: