xpay tweaks and fixes

common/gossmap.c

@@ -1056,6 +1056,8 @@ bool gossmap_local_addchan(struct gossmap_localmods *localmods,
 	u64 off;
 	struct localmod mod;
 
+	assert(!node_id_eq(n1, n2));
+
 	/* Don't create duplicate channels. */
 	if (find_localmod(localmods, scid))
 		return false;

common/gossmap.h

@@ -89,6 +89,7 @@ struct gossmap_localmods *gossmap_localmods_new(const tal_t *ctx);
 /* Create a local-only channel; if this conflicts with a real channel when added,
  * that will be used instead.
  * Returns false (and does nothing) if scid was already in localmods.
+ * n1 must be different from n2.
  */
 bool gossmap_local_addchan(struct gossmap_localmods *localmods,
 			   const struct node_id *n1,

contrib/msggen/msggen/schema.json

@@ -652,7 +652,7 @@
           "destination": {
             "type": "pubkey",
             "description": [
-              "The destination node id for the channel."
+              "The destination node id for the channel (must be different from source)."
             ]
           },
           "short_channel_id": {

doc/schemas/askrene-create-channel.json

@@ -32,7 +32,7 @@
       "destination": {
         "type": "pubkey",
         "description": [
-          "The destination node id for the channel."
+          "The destination node id for the channel (must be different from source)."
         ]
       },
       "short_channel_id": {

plugins/askrene/askrene.c

@@ -1066,6 +1066,10 @@ static struct command_result *json_askrene_create_channel(struct command *cmd,
 	plugin_log(cmd->plugin, LOG_TRACE, "%s called: %.*s", __func__,
 		   json_tok_full_len(params), json_tok_full(buffer, params));
 
+	if (node_id_cmp(src, dst) == 0)
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				    "source and destination must be different");
+
 	if (layer_find_local_channel(layer, *scid)) {
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
 				    "channel already exists");

plugins/askrene/layer.c

@@ -234,6 +234,7 @@ static struct local_channel *add_local_channel(struct layer *layer,
 		lc->n1 = *n1;
 		lc->n2 = *n2;
 	} else {
+		assert(!node_id_eq(n1, n2));
 		lc->n1 = *n2;
 		lc->n2 = *n1;
 	}

plugins/askrene/layer.h

@@ -52,7 +52,7 @@ bool layer_check_local_channel(const struct local_channel *lc,
 			       const struct node_id *n2,
 			       struct amount_msat capacity);
 
-/* Add a local channel to a layer! */
+/* Add a local channel to a layer: src must not be equal to dst!*/
 void layer_add_local_channel(struct layer *layer,
 			     const struct node_id *src,
 			     const struct node_id *dst,

plugins/xpay/xpay.c

@@ -1922,6 +1922,16 @@ static void add_fake_channel(struct command *aux_cmd,
 	struct out_req *req;
 	struct short_channel_id_dir scidd;
 
+	/* We're not allowed to send these to askrene-create-channel,
+	 * so catch them now */
+	if (node_id_eq(src, dst)) {
+		payment_log(payment, LOG_UNUSUAL,
+			    "Invoice gave bad self-node route %s->%s",
+			    fmt_node_id(tmpctx, src),
+			    fmt_node_id(tmpctx, dst));
+		return;
+	}
+
 	scidd.scid = scid;
 	scidd.dir = node_id_idx(src, dst);
 	payment_log(payment, LOG_DBG,
@@ -2153,7 +2163,8 @@ static struct command_result *check_offer_payable(struct command *cmd,
 	/* We will only one-shot if we know amount!  (FIXME: Convert!) */
 	if (b12offer->offer_currency)
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
-				    "Cannot pay offer in different currency %s",
+				    "Cannot pay offer in different currency %.*s",
+				    (int)tal_bytelen(b12offer->offer_currency),
 				    b12offer->offer_currency);
 	if (b12offer->offer_amount) {
 		if (msat && !amount_msat_eq(amount_msat(*b12offer->offer_amount), *msat)) {
@@ -2188,7 +2199,8 @@ check_offer_sendamount_payable(struct command *cmd, const char *offerstr)
 	/* FIXME: add currency support */
 	if (b12offer->offer_currency)
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
-				    "Cannot pay offer in different currency %s",
+				    "Cannot pay offer in different currency %.*s",
+				    (int)tal_bytelen(b12offer->offer_currency),
 				    b12offer->offer_currency);
 	/* Can only be applied to *any amount* offers. */
 	if (b12offer->offer_amount)

tests/test_xpay.py

@@ -975,6 +975,47 @@ def test_xpay_offer(node_factory):
     l1.rpc.xpay(offer2, 5000)
 
 
+def test_xpay_circular_routehint(node_factory):
+    """Test that xpay gracefully skips a circular bolt11 routehint (src == dst)."""
+    l1, l2 = node_factory.line_graph(2)
+
+    # A routehint containing a same-node channel (example is l3 in this case)
+    circular_hint = [{'id': '03cecbfdc68544cc596223b68ce0710c9e5d2c9cb317ee07822d95079acc703d31',
+                      'short_channel_id': '1x2x3',
+                      'fee_base_msat': 0,
+                      'fee_proportional_millionths': 0,
+                      'cltv_expiry_delta': 6},
+                     {'id': '03cecbfdc68544cc596223b68ce0710c9e5d2c9cb317ee07822d95079acc703d31',
+                      'short_channel_id': '1x2x4',
+                      'fee_base_msat': 0,
+                      'fee_proportional_millionths': 0,
+                      'cltv_expiry_delta': 6}]
+    inv = l2.dev_invoice(amount_msat=10000,
+                         label='circular_hint',
+                         description='circular hint test',
+                         dev_routes=[circular_hint])
+
+    # Payment should still succeed via the direct channel.
+    ret = l1.rpc.xpay(inv['bolt11'])
+    assert ret['successful_parts'] == 1
+    l1.daemon.wait_for_log('Invoice gave bad self-node route')
+
+
+def test_xpay_currency_offer(node_factory):
+    """Test that xpay and sendamount correctly report the currency name when rejecting non-msat offers."""
+    plugin = Path(__file__).parent / "plugins" / "currencyUSDAUD5000.py"
+    l1, l2 = node_factory.line_graph(2, wait_for_announce=True,
+                                     opts=[{}, {'plugin': str(plugin)}])
+
+    offerusd = l2.rpc.offer('10USD', 'USD test')['bolt12']
+
+    with pytest.raises(RpcError, match=r"Cannot pay offer in different currency USD"):
+        l1.rpc.xpay(offerusd)
+
+    with pytest.raises(RpcError, match=r"Cannot pay offer in different currency USD"):
+        l1.rpc.sendamount(offerusd, '100sat')
+
+
 def test_xpay_bip353(node_factory):
     fakebip353_plugin = Path(__file__).parent / "plugins" / "fakebip353.py"