lnpeer: fix logging of 'will fullfill htlc'

electrum/lnpeer.py

@@ -1833,7 +1833,8 @@ class Peer(Logger):
         if not (invoice_msat is None or invoice_msat <= total_msat <= 2 * invoice_msat):
             log_fail_reason(f"total_msat={total_msat} too different from invoice_msat={invoice_msat}")
             raise exc_incorrect_or_unknown_pd
-        self.logger.info(f"maybe_fulfill_htlc. will FULFILL HTLC: chan {chan.short_channel_id}. htlc={str(htlc)}")
+        if preimage:
+            self.logger.info(f"maybe_fulfill_htlc. will FULFILL HTLC: chan {chan.short_channel_id}. htlc={str(htlc)}")
         self.lnworker.set_request_status(htlc.payment_hash, PR_PAID)
         return preimage, None