trivial: use "chunks()" for htlc_sigs in lnchannel

electrum/lnchannel.py

@@ -32,7 +32,7 @@ import attr
 
 from . import ecc
 from . import constants
-from .util import bfh, bh2u
+from .util import bfh, bh2u, chunks
 from .bitcoin import redeem_script_to_address
 from .crypto import sha256, sha256d
 from .transaction import Transaction, PartialTransaction
@@ -628,7 +628,7 @@ class Channel(Logger):
 
     def get_remote_htlc_sig_for_htlc(self, *, htlc_relative_idx: int) -> bytes:
         data = self.config[LOCAL].current_htlc_signatures
-        htlc_sigs = [data[i:i + 64] for i in range(0, len(data), 64)]
+        htlc_sigs = list(chunks(data, 64))
         htlc_sig = htlc_sigs[htlc_relative_idx]
         remote_htlc_sig = ecc.der_sig_from_sig_string(htlc_sig) + b'\x01'
         return remote_htlc_sig

electrum/lnpeer.py

@@ -1076,7 +1076,7 @@ class Peer(Logger):
         if chan.hm.is_revack_pending(LOCAL):
             raise RemoteMisbehaving('received commitment_signed before we revoked previous ctx')
         data = payload["htlc_signature"]
-        htlc_sigs = [data[i:i+64] for i in range(0, len(data), 64)]
+        htlc_sigs = list(chunks(data, 64))
         chan.receive_new_commitment(payload["signature"], htlc_sigs)
         self.send_revoke_and_ack(chan)
 

electrum/tests/test_util.py

@@ -108,6 +108,9 @@ class TestUtil(ElectrumTestCase):
     def test_chunks(self):
         self.assertEqual([[1, 2], [3, 4], [5]],
                          list(chunks([1, 2, 3, 4, 5], 2)))
+        self.assertEqual([], list(chunks(b'', 64)))
+        self.assertEqual([b'12', b'34', b'56'],
+                         list(chunks(b'123456', 2)))
         with self.assertRaises(ValueError):
             list(chunks([1, 2, 3], 0))