From 0cb17bbbe5dff89a72ac3f77a45d4cb6dc3caf31 Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Wed, 2 Jul 2025 12:11:26 +0200
Subject: [PATCH] graph/db: migrate closed SCID index

This commit expands `MigrateGraphToSQL` to include the migration of the
closed-scid index.
---
 graph/db/sql_migration.go      | 73 ++++++++++++++++++++++++++++++++++
 graph/db/sql_migration_test.go | 34 ++++++++++++++++
 2 files changed, 107 insertions(+)

diff --git a/graph/db/sql_migration.go b/graph/db/sql_migration.go
index 71b1b201a..5a0aa1422 100644
--- a/graph/db/sql_migration.go
+++ b/graph/db/sql_migration.go
@@ -14,6 +14,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/kvdb"
+	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/sqldb"
 	"github.com/lightningnetwork/lnd/sqldb/sqlc"
 )
@@ -62,6 +63,13 @@ func MigrateGraphToSQL(ctx context.Context, kvBackend kvdb.Backend,
 		return fmt.Errorf("could not migrate prune log: %w", err)
 	}
 
+	// 5) Migrate the closed SCID index.
+	err = migrateClosedSCIDIndex(ctx, kvBackend, sqlDB)
+	if err != nil {
+		return fmt.Errorf("could not migrate closed SCID index: %w",
+			err)
+	}
+
 	log.Infof("Finished migration of the graph store from KV to SQL in %v",
 		time.Since(t0))
 
@@ -686,3 +694,68 @@ func forEachPruneLogEntry(db kvdb.Backend, cb func(height uint32,
 		})
 	}, func() {})
 }
+
+// migrateClosedSCIDIndex migrates the closed SCID index from the KV backend to
+// the SQL database. It iterates over each closed SCID in the KV store, inserts
+// it into the SQL database, and then verifies that the SCID was inserted
+// correctly by checking if the channel with the given SCID is seen as closed in
+// the SQL database.
+func migrateClosedSCIDIndex(ctx context.Context, kvBackend kvdb.Backend,
+	sqlDB SQLQueries) error {
+
+	var count uint64
+	migrateSingleClosedSCID := func(scid lnwire.ShortChannelID) error {
+		count++
+
+		chanIDB := channelIDToBytes(scid.ToUint64())
+		err := sqlDB.InsertClosedChannel(ctx, chanIDB)
+		if err != nil {
+			return fmt.Errorf("could not insert closed channel "+
+				"with SCID %s: %w", scid, err)
+		}
+
+		// Now, verify that the channel with the given SCID is
+		// seen as closed.
+		isClosed, err := sqlDB.IsClosedChannel(ctx, chanIDB)
+		if err != nil {
+			return fmt.Errorf("could not check if channel %s "+
+				"is closed: %w", scid, err)
+		}
+
+		if !isClosed {
+			return fmt.Errorf("channel %s should be closed, "+
+				"but is not", scid)
+		}
+
+		return nil
+	}
+
+	err := forEachClosedSCID(kvBackend, migrateSingleClosedSCID)
+	if err != nil {
+		return fmt.Errorf("could not migrate closed SCID index: %w",
+			err)
+	}
+
+	log.Infof("Migrated %d closed SCIDs from KV to SQL", count)
+
+	return nil
+}
+
+// forEachClosedSCID iterates over each closed SCID in the KV backend and calls
+// the provided callback function for each SCID.
+func forEachClosedSCID(db kvdb.Backend,
+	cb func(lnwire.ShortChannelID) error) error {
+
+	return kvdb.View(db, func(tx kvdb.RTx) error {
+		closedScids := tx.ReadBucket(closedScidBucket)
+		if closedScids == nil {
+			return nil
+		}
+
+		return closedScids.ForEach(func(k, _ []byte) error {
+			return cb(lnwire.NewShortChanIDFromInt(
+				byteOrder.Uint64(k),
+			))
+		})
+	}, func() {})
+}
diff --git a/graph/db/sql_migration_test.go b/graph/db/sql_migration_test.go
index b2b884261..eb081b772 100644
--- a/graph/db/sql_migration_test.go
+++ b/graph/db/sql_migration_test.go
@@ -258,6 +258,22 @@ func TestMigrateGraphToSQL(t *testing.T) {
 				pruneTip:   20,
 			},
 		},
+		{
+			name: "closed SCID index",
+			write: func(t *testing.T, db *KVStore, object any) {
+				scid, ok := object.(lnwire.ShortChannelID)
+				require.True(t, ok)
+
+				err := db.PutClosedScid(scid)
+				require.NoError(t, err)
+			},
+			objects: []any{
+				lnwire.NewShortChanIDFromInt(1),
+				lnwire.NewShortChanIDFromInt(2),
+				lnwire.NewShortChanIDFromInt(3),
+				lnwire.NewShortChanIDFromInt(4),
+			},
+		},
 	}
 
 	for _, test := range tests {
@@ -324,6 +340,11 @@ func assertInSync(t *testing.T, kvDB *KVStore, sqlDB *SQLStore,
 	// entries in the SQL store. Then we just do a final check to ensure
 	// that the prune tip also matches.
 	checkKVPruneLogEntries(t, kvDB, sqlDB, stats.pruneTip)
+
+	// 5) Assert that the closed SCID index is also in sync. Like the prune
+	// log we iterate through the kvdb store and check that the entries
+	// match the entries in the SQL store.
+	checkClosedSCIDIndex(t, kvDB.db, sqlDB)
 }
 
 // fetchAllNodes retrieves all nodes from the given store and returns them
@@ -467,6 +488,19 @@ func checkKVPruneLogEntries(t *testing.T, kv *KVStore, sql *SQLStore,
 	require.Equal(t, expTip, int(sqlPruneHeight))
 }
 
+// checkClosedSCIDIndex iterates through the closed SCID index in the
+// KVStore and checks that each SCID is marked as closed in the SQLStore.
+func checkClosedSCIDIndex(t *testing.T, kv kvdb.Backend, sql *SQLStore) {
+	err := forEachClosedSCID(kv, func(scid lnwire.ShortChannelID) error {
+		closed, err := sql.IsClosedScid(scid)
+		require.NoError(t, err)
+		require.True(t, closed)
+
+		return nil
+	})
+	require.NoError(t, err)
+}
+
 // setUpKVStore initializes a new KVStore for testing.
 func setUpKVStore(t *testing.T) *KVStore {
 	kvDB, cleanup, err := kvdb.GetTestBackend(t.TempDir(), "graph")