plugins: re-enable listchannels local info in deprecated mode.

We only deprecated this, we didn't actually remove it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

doc/lightning-listchannels.7.md

@@ -44,7 +44,7 @@ On success, an object containing **channels** is returned.  It is an array of ob
 - **amount\_msat** (msat): the total capacity of this channel (always a whole number of satoshis)
 - **message\_flags** (u8): as defined by BOLT #7
 - **channel\_flags** (u8): as defined by BOLT #7
-- **active** (boolean): true unless source has disabled it, or it's a local channel and the peer is disconnected or it's still opening or closing
+- **active** (boolean): true unless source has disabled it (or (deprecated in *v24.02*) it's a local channel and the peer is disconnected or it's still opening or closing)
 - **last\_update** (u32): UNIX timestamp on the last channel\_update from *source*
 - **base\_fee\_millisatoshi** (u32): Base fee changed by *source* to use this channel
 - **fee\_per\_millionth** (u32): Proportional fee changed by *source* to use this channel, in parts-per-million
@@ -83,4 +83,4 @@ Lightning RFC site
 -   BOLT \#7:
     <https://github.com/lightning/bolts/blob/master/07-routing-gossip.md>
 
-[comment]: # ( SHA256STAMP:5e729a362943aa9481cc12e410c1f507020983251871fbac497dbb8679ca36ca)
+[comment]: # ( SHA256STAMP:c32fcbcb0d0ba926513978a96e6b68ee9e3d7f732b5a9cc167aa77cdd33d717f)

plugins/topology.c

@@ -345,6 +345,29 @@ static struct node_map *local_connected(const tal_t *ctx,
 	return connected;
 }
 
+/* Only add a local entry if it's unknown publicly */
+static void gossmod_add_unknown_localchan(struct gossmap_localmods *mods,
+					  const struct node_id *self,
+					  const struct node_id *peer,
+					  const struct short_channel_id_dir *scidd,
+					  struct amount_msat min,
+					  struct amount_msat max,
+					  struct amount_msat fee_base,
+					  u32 fee_proportional,
+					  u32 cltv_delta,
+					  bool enabled,
+					  const char *buf UNUSED,
+					  const jsmntok_t *chantok UNUSED,
+					  struct gossmap *gossmap)
+{
+	if (gossmap_find_chan(gossmap, &scidd->scid))
+		return;
+
+	gossmod_add_localchan(mods, self, peer, scidd, min, max,
+			      fee_base, fee_proportional, cltv_delta, enabled,
+			      buf, chantok, gossmap);
+}
+
 /* FIXME: We don't need this listpeerchannels at all if not deprecated! */
 static struct command_result *listpeerchannels_done(struct command *cmd,
 					     const char *buf,
@@ -355,12 +378,23 @@ static struct command_result *listpeerchannels_done(struct command *cmd,
 	struct gossmap_chan *c;
 	struct json_stream *js;
 	struct gossmap *gossmap = get_gossmap();
+	struct gossmap_localmods *mods;
 
 	if (deprecated_apis)
 		connected = local_connected(opts, buf, result);
 	else
 		connected = NULL;
 
+	/* In deprecated mode, re-add private channels */
+	if (deprecated_apis) {
+		mods = gossmods_from_listpeerchannels(tmpctx, &local_id,
+						      buf, result,
+						      gossmod_add_unknown_localchan,
+						      gossmap);
+		gossmap_apply_localmods(gossmap, mods);
+	} else
+		mods = NULL;
+
 	js = jsonrpc_stream_success(cmd);
 	json_array_start(js, "channels");
 	if (opts->scid) {
@@ -401,6 +435,9 @@ static struct command_result *listpeerchannels_done(struct command *cmd,
 
 	json_array_end(js);
 
+	if (mods)
+		gossmap_remove_localmods(gossmap, mods);
+
 	return command_finished(cmd, js);
 }
 

tests/test_gossip.py

@@ -6,7 +6,8 @@
 from utils import (
     wait_for, TIMEOUT, only_one, sync_blockheight,
     expected_node_features,
-    mine_funding_to_announce, default_ln_port, CHANNEL_SIZE
+    mine_funding_to_announce, default_ln_port, CHANNEL_SIZE,
+    first_scid,
 )
 
 import json
@@ -2334,3 +2335,36 @@ def test_read_spam_nannounce(node_factory, bitcoind):
     l1.daemon.wait_for_log('Received node_announcement')
     l1.restart()
     assert not l1.daemon.is_in_log('BROKEN')
+
+
+def test_listchannels_deprecated_local(node_factory, bitcoind):
+    """Test listchannels shows local/private channels only in deprecated mode"""
+    l1, l2, l3 = node_factory.get_nodes(3,
+                                        opts=[{}, {'allow-deprecated-apis': True}, {}])
+    # This will be in block 103
+    node_factory.join_nodes([l1, l2], wait_for_announce=False)
+    l1l2 = first_scid(l1, l2)
+    # This will be in block 104
+    node_factory.join_nodes([l2, l3], wait_for_announce=False)
+    l2l3 = first_scid(l2, l3)
+
+    # Non-deprecated nodes say no.
+    assert l1.rpc.listchannels() == {'channels': []}
+    assert l3.rpc.listchannels() == {'channels': []}
+    # Deprecated API lists both sides of local channels:
+
+    vals = [(c['active'], c['public'], c['short_channel_id']) for c in l2.rpc.listchannels()['channels']]
+    # Either order
+    assert vals == [(True, False, l1l2)] * 2 + [(True, False, l2l3)] * 2 or vals == [(True, False, l2l3)] * 2 + [(True, False, l1l2)] * 2
+
+    # Mine l1-l2 channel so it's public.
+    bitcoind.generate_block(4)
+    sync_blockheight(bitcoind, [l1, l2, l3])
+
+    wait_for(lambda: len(l1.rpc.listchannels()['channels']) == 2)
+    wait_for(lambda: len(l3.rpc.listchannels()['channels']) == 2)
+
+    # l2 shows public one correctly, and private one correctly
+    # Either order
+    vals = [(c['active'], c['public'], c['short_channel_id']) for c in l2.rpc.listchannels()['channels']]
+    assert vals == [(True, True, l1l2)] * 2 + [(True, False, l2l3)] * 2 or vals == [(True, False, l2l3)] * 2 + [(True, True, l1l2)] * 2