From dfb963e2494bb1003b268193ad79129112739f0d Mon Sep 17 00:00:00 2001
From: Christian Decker <decker.christian@gmail.com>
Date: Thu, 24 Nov 2022 17:55:04 +0100
Subject: [PATCH] db: Backfill missing HTLC IDs in the forwards table

We have a primary key that is spanning the `in_channel_id` and the
`in_htcl_id`. The latter gets set to NULL when the HTLC and channel
gets deleted, so we coalesce with a random large number that is
unlikely to collide for the primary key.
---
 devtools/sql-rewrite.py | 1 +
 tests/test_db.py        | 3 +++
 wallet/db.c             | 5 ++++-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/devtools/sql-rewrite.py b/devtools/sql-rewrite.py
index 7ae209403c3b..03c358a643c7 100755
--- a/devtools/sql-rewrite.py
+++ b/devtools/sql-rewrite.py
@@ -75,6 +75,7 @@ def rewrite_single(self, q):
 
         typemapping = {
             r'BLOB': 'BYTEA',
+            r'_ROWID_': '(((ctid::text::point)[0]::bigint << 32) | (ctid::text::point)[1]::bigint)',  # Yeah, I know...
             r'CURRENT_TIMESTAMP\(\)': "EXTRACT(epoch FROM now())",
         }
 
diff --git a/tests/test_db.py b/tests/test_db.py
index 8b1ac2969d4b..eccb492add99 100644
--- a/tests/test_db.py
+++ b/tests/test_db.py
@@ -508,6 +508,9 @@ def test_db_forward_migrate(bitcoind, node_factory):
     assert l1.rpc.getinfo()['fees_collected_msat'] == 4
     assert len(l1.rpc.listforwards()['forwards']) == 4
 
+    # The two null in_htlc_id are replaced with bogus entries!
+    assert sum([f['in_htlc_id'] > 0xFFFFFFFFFFFF for f in l1.rpc.listforwards()['forwards']]) == 2
+
     # Make sure autoclean can handle these!
     l1.stop()
     l1.daemon.opts['autoclean-succeededforwards-age'] = 2
diff --git a/wallet/db.c b/wallet/db.c
index 6418a1924f36..6b39a44050de 100644
--- a/wallet/db.c
+++ b/wallet/db.c
@@ -912,7 +912,10 @@ static struct migration dbmigrations[] = {
 	 ", PRIMARY KEY(in_channel_scid, in_htlc_id))"), NULL},
     {SQL("INSERT INTO forwards SELECT"
 	 " in_channel_scid"
-	 ", (SELECT channel_htlc_id FROM channel_htlcs WHERE id = forwarded_payments.in_htlc_id)"
+	 ", COALESCE("
+	 "    (SELECT channel_htlc_id FROM channel_htlcs WHERE id = forwarded_payments.in_htlc_id),"
+	 "    -_ROWID_"
+	 "  )"
 	 ", out_channel_scid"
 	 ", (SELECT channel_htlc_id FROM channel_htlcs WHERE id = forwarded_payments.out_htlc_id)"
 	 ", in_msatoshi"