From 96c2f520f265060948bca208e46f9f14195058c7 Mon Sep 17 00:00:00 2001
From: Lagrang3 <lagrang3@protonmail.com>
Date: Mon, 15 Jun 2026 13:43:01 +0100
Subject: [PATCH 1/2] askrene-getroutes: add test for source==destination

Changelog-None

Signed-off-by: Lagrang3 <lagrang3@protonmail.com>
---
 tests/test_askrene.py | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/tests/test_askrene.py b/tests/test_askrene.py
index 9fbc9e708672..6d05583f600f 100644
--- a/tests/test_askrene.py
+++ b/tests/test_askrene.py
@@ -2667,3 +2667,45 @@ def test_impossible_payment(node_factory):
             final_cltv=5,
             maxparts=1,
         )
+
+
+@pytest.mark.xfail(strict=True)
+def test_bad_user_entries(node_factory):
+    """Test bad user entries that should result in an RPC error and not crash
+    lightningd."""
+    l1 = node_factory.get_node()
+    node1 = "020000000000000000000000000000000000000000000000000000000000000001"
+    node2 = "020000000000000000000000000000000000000000000000000000000000000002"
+    million_sats = 1000000000
+    l1.rpc.askrene_create_layer("mylayer")
+    l1.rpc.askrene_create_channel(
+        layer="mylayer",
+        source=node1,
+        destination=node2,
+        short_channel_id="0x0x1",
+        capacity_msat=million_sats,
+    )
+    l1.rpc.askrene_update_channel(
+        layer="mylayer",
+        short_channel_id_dir="0x0x1/0",
+        enabled=True,
+        htlc_minimum_msat=0,
+        htlc_maximum_msat=million_sats,
+        fee_base_msat=0,
+        fee_proportional_millionths=0,
+        cltv_expiry_delta=18,
+    )
+
+    # Try querying getroutes with source==destination
+    with pytest.raises(
+        RpcError,
+        match=r"source and destination must be different",
+    ):
+        l1.rpc.getroutes(
+            source=node1,
+            destination=node1,
+            amount_msat=1000,
+            layers=["mylayer"],
+            maxfee_msat=2000,
+            final_cltv=5,
+        )

From 66722a27d6a6bee348f531327e36b132c4a871d9 Mon Sep 17 00:00:00 2001
From: Lagrang3 <lagrang3@protonmail.com>
Date: Mon, 15 Jun 2026 13:43:55 +0100
Subject: [PATCH 2/2] getroutes: don't crash on source==destination

```
cln-askrene: plugins/askrene/child/child.c:40: final_hop: Assertion `tal_count(hops) > 0' failed.
cln-askrene: FATAL SIGNAL 6 (version v26.06-19-g46b039d)
lightningd-1 2026-06-15T12:34:26.296Z DEBUG   plugin-cln-askrene: notify msg debug: Final answer has 1 flows
0x55ab65429902 send_backtrace
	common/daemon.c:38
0x55ab6542998c crashdump
	common/daemon.c:83
0x7fbc84a8bdef ???
	./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
0x7fbc84ae095c __pthread_kill_implementation
	./nptl/pthread_kill.c:44
0x7fbc84a8bcc1 __GI_raise
	../sysdeps/posix/raise.c:26
0x7fbc84a744ab __GI_abort
	./stdlib/abort.c:77
0x7fbc84a7441f __assert_fail_base
	./assert/assert.c:118
0x55ab6541b60c final_hop
	plugins/askrene/child/child.c:40
0x55ab6541b70d fmt_route
	plugins/askrene/child/child.c:48
0x55ab6541ba5b convert_flows_to_routes
	plugins/askrene/child/child.c:135
0x55ab6541c037 run_child
	plugins/askrene/child/child.c:265
0x55ab65416caa do_getroutes
	plugins/askrene/askrene.c:711
0x55ab65416d28 begin_request
	plugins/askrene/askrene.c:887
0x55ab654170a2 json_getroutes
	plugins/askrene/askrene.c:968
0x55ab654285ec ld_command_handle
	plugins/libplugin.c:2206
0x55ab654287f6 ld_read_json
	plugins/libplugin.c:2282
0x55ab65439261 next_plan
	ccan/ccan/io/io.c:60
0x55ab65439580 do_plan
	ccan/ccan/io/io.c:422
0x55ab65439639 io_ready
	ccan/ccan/io/io.c:439
0x55ab6543a5fc io_loop
	ccan/ccan/io/poll.c:470
0x55ab65428bc4 plugin_main
	plugins/libplugin.c:2481
0x55ab65417491 main
	plugins/askrene/askrene.c:1551
0x7fbc84a75ca7 __libc_start_call_main
	../sysdeps/nptl/libc_start_call_main.h:58
0x7fbc84a75d64 __libc_start_main_impl
	../csu/libc-start.c:360
0x55ab65413920 ???
	_start+0x20:0
0xffffffffffffffff ???
	???:0
```

Changelog-Fixed: askrene-getroutes: don't crash on invalid user input, source==destination

Signed-off-by: Lagrang3 <lagrang3@protonmail.com>
---
 plugins/askrene/askrene.c | 5 +++++
 tests/test_askrene.py     | 1 -
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/plugins/askrene/askrene.c b/plugins/askrene/askrene.c
index 736054ebab7b..70247c1ea189 100644
--- a/plugins/askrene/askrene.c
+++ b/plugins/askrene/askrene.c
@@ -943,6 +943,11 @@ static struct command_result *json_getroutes(struct command *cmd,
 				    maxdelay_allowed);
 	}
 
+	if (node_id_eq(source, dest)) {
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				    "source and destination must be different");
+	}
+
 	if (command_check_only(cmd))
 		return command_check_done(cmd);
 
diff --git a/tests/test_askrene.py b/tests/test_askrene.py
index 6d05583f600f..4474ec321dfe 100644
--- a/tests/test_askrene.py
+++ b/tests/test_askrene.py
@@ -2669,7 +2669,6 @@ def test_impossible_payment(node_factory):
         )
 
 
-@pytest.mark.xfail(strict=True)
 def test_bad_user_entries(node_factory):
     """Test bad user entries that should result in an RPC error and not crash
     lightningd."""