walletdb: chan dict: small clean-up (incl db upgrade)

- "fail_htlc_reasons" was removed in 9b1c40e396
- "unfulfilled_htlcs": rm 2 dead items from the 4-tuple,
   and convert False value of forwarding_key

electrum/lnchannel.py

@@ -662,7 +662,8 @@ class Channel(AbstractChannel):
         self.onion_keys = state['onion_keys']  # type: Dict[int, bytes]
         self.data_loss_protect_remote_pcp = state['data_loss_protect_remote_pcp']
         self.hm = HTLCManager(log=state['log'], initial_feerate=initial_feerate)
-        self.unfulfilled_htlcs = state["unfulfilled_htlcs"]
+        self.unfulfilled_htlcs = state["unfulfilled_htlcs"]  # type: Dict[int, Tuple[str, Optional[str]]]
+        # ^ htlc_id -> onion_packet_hex, forwarding_key
         self._state = ChannelState[state['state']]
         self.peer_state = PeerState.DISCONNECTED
         self._sweep_info = {}
@@ -1058,11 +1059,8 @@ class Channel(AbstractChannel):
             htlc = attr.evolve(htlc, htlc_id=self.hm.get_next_htlc_id(REMOTE))
         with self.db_lock:
             self.hm.recv_htlc(htlc)
-            local_ctn = self.get_latest_ctn(LOCAL)
-            remote_ctn = self.get_latest_ctn(REMOTE)
             if onion_packet:
-                # TODO neither local_ctn nor remote_ctn are used anymore... no point storing them.
-                self.unfulfilled_htlcs[htlc.htlc_id] = local_ctn, remote_ctn, onion_packet.hex(), False
+                self.unfulfilled_htlcs[htlc.htlc_id] = onion_packet.hex(), None
 
         self.logger.info("receive_htlc")
         return htlc

electrum/lnpeer.py

@@ -950,8 +950,7 @@ class Peer(Logger):
             'onion_keys': {},
             'data_loss_protect_remote_pcp': {},
             "log": {},
-            "fail_htlc_reasons": {},  # htlc_id -> onion_packet
-            "unfulfilled_htlcs": {},  # htlc_id -> error_bytes, failure_message
+            "unfulfilled_htlcs": {},
             "revocation_store": {},
             "channel_type": channel_type,
         }
@@ -2610,10 +2609,9 @@ class Peer(Logger):
                 self.maybe_send_commitment(chan)
                 done = set()
                 unfulfilled = chan.unfulfilled_htlcs
-                for htlc_id, (local_ctn, remote_ctn, onion_packet_hex, forwarding_key) in unfulfilled.items():
+                for htlc_id, (onion_packet_hex, forwarding_key) in unfulfilled.items():
                     if not chan.hm.is_htlc_irrevocably_added_yet(htlc_proposer=REMOTE, htlc_id=htlc_id):
                         continue
-                    forwarding_key = forwarding_key or None  # type: Optional[str]
                     htlc = chan.hm.get_htlc_by_id(REMOTE, htlc_id)
                     error_reason = None  # type: Optional[OnionRoutingFailure]
                     error_bytes = None  # type: Optional[bytes]
@@ -2634,7 +2632,7 @@ class Peer(Logger):
                                 onion_packet=onion_packet)
                             if _forwarding_key:
                                 assert forwarding_key is None
-                                unfulfilled[htlc_id] = local_ctn, remote_ctn, onion_packet_hex, _forwarding_key
+                                unfulfilled[htlc_id] = onion_packet_hex, _forwarding_key
                         except OnionRoutingFailure as e:
                             error_bytes = construct_onion_error(e, onion_packet.public_key, our_onion_private_key=self.privkey)
                         if error_bytes:

electrum/wallet_db.py

@@ -72,7 +72,7 @@ class WalletUnfinished(WalletFileException):
 # seed_version is now used for the version of the wallet file
 OLD_SEED_VERSION = 4        # electrum versions < 2.0
 NEW_SEED_VERSION = 11       # electrum versions >= 2.0
-FINAL_SEED_VERSION = 58     # electrum >= 2.7 will set this to prevent
+FINAL_SEED_VERSION = 59     # electrum >= 2.7 will set this to prevent
                             # old versions from overwriting new format
 
 
@@ -111,7 +111,7 @@ json_db.register_dict('contacts', tuple, None)
 # register dicts that require key conversion
 for key in [
         'adds', 'locked_in', 'settles', 'fails', 'fee_updates', 'buckets',
-        'unacked_updates', 'unfulfilled_htlcs', 'fail_htlc_reasons', 'onion_keys']:
+        'unacked_updates', 'unfulfilled_htlcs', 'onion_keys']:
     json_db.register_dict_key(key, int)
 for key in ['log']:
     json_db.register_dict_key(key, lambda x: HTLCOwner(int(x)))
@@ -233,6 +233,7 @@ class WalletDBUpgrader(Logger):
         self._convert_version_56()
         self._convert_version_57()
         self._convert_version_58()
+        self._convert_version_59()
         self.put('seed_version', FINAL_SEED_VERSION)  # just to be sure
 
     def _convert_wallet_type(self):
@@ -1132,6 +1133,19 @@ class WalletDBUpgrader(Logger):
         self.put('prevouts_by_scripthash', prevouts_by_scripthash)
         self.data['seed_version'] = 58
 
+    def _convert_version_59(self):
+        if not self._is_upgrade_method_needed(58, 58):
+            return
+        channels = self.data.get('channels', {})
+        for _key, chan in channels.items():
+            chan.pop('fail_htlc_reasons', {})
+            unfulfilled_htlcs = {}
+            for htlc_id, (local_ctn, remote_ctn, onion_packet_hex, forwarding_key) in chan['unfulfilled_htlcs'].items():
+                unfulfilled_htlcs[htlc_id] = (onion_packet_hex, forwarding_key or None)
+            chan['unfulfilled_htlcs'] = unfulfilled_htlcs
+        self.data['channels'] = channels
+        self.data['seed_version'] = 59
+
     def _convert_imported(self):
         if not self._is_upgrade_method_needed(0, 13):
             return

tests/test_lnchannel.py

@@ -108,7 +108,6 @@ def create_channel_state(funding_txid, funding_index, funding_sat, is_initiator,
             'data_loss_protect_remote_pcp': {},
             'state': 'PREOPENING',
             'log': {},
-            'fail_htlc_reasons': {},
             'unfulfilled_htlcs': {},
             'revocation_store': {},
             'channel_type': lnutil.ChannelType.OPTION_STATIC_REMOTEKEY