db: fix dangling peers on db upgrade.

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

tests/test_db.py

@@ -1,9 +1,6 @@
 from fixtures import *  # noqa: F401,F403
 
-import pytest
 
-
-@pytest.mark.xfail(strict=True)
 def test_db_dangling_peer_fix(node_factory):
     # This was taken from test_fail_unconfirmed() node.
     l1 = node_factory.get_node(dbfile='dangling-peer.sqlite3.xz')

wallet/db.c

@@ -356,6 +356,8 @@ char *dbmigrations[] = {
     ");",
     /* Add a direction for failed payments. */
     "ALTER TABLE payments ADD faildirection INTEGER;", /* erring_direction */
+    /* Fix dangling peers with no channels. */
+    "DELETE FROM peers WHERE id NOT IN (SELECT peer_id FROM channels);",
     NULL,
 };