fix receiving lightning requests without amount

electrum/lnworker.py

@@ -1789,6 +1789,7 @@ class LNWallet(LNWorker):
             write_to_disk: bool = True,
     ) -> Tuple[LnAddr, str]:
 
+        assert amount_msat is None or amount_msat > 0
         timestamp = int(time.time())
         routing_hints = self.calc_routing_hints_for_invoice(amount_msat)
         if not routing_hints:
@@ -1831,7 +1832,7 @@ class LNWallet(LNWorker):
 
     def add_request(self, amount_sat: Optional[int], message:str, expiry: int, fallback_address:str) -> str:
         # passed expiry is relative, it is absolute in the lightning invoice
-        amount_msat = amount_sat * 1000 if amount_sat is not None else None
+        amount_msat = amount_sat * 1000 if amount_sat else None
         timestamp = int(time.time())
         lnaddr, invoice = self.create_invoice(
             amount_msat=amount_msat,
@@ -1932,7 +1933,8 @@ class LNWallet(LNWorker):
             return
         if info is None and status == PR_SCHEDULED:
             # we should add a htlc to our ctx, so that the funds are 'reserved'
-            info = PaymentInfo(payment_hash, 0, SENT, PR_SCHEDULED)
+            # Note: info.amount will be added by pay_invoice
+            info = PaymentInfo(payment_hash, None, SENT, PR_SCHEDULED)
         info = info._replace(status=status)
         self.save_payment_info(info)