From 902611d86a6d2ce2102df3b61f14c042fdc55f98 Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Fri, 11 Jul 2025 13:35:00 +0200
Subject: [PATCH] lnd: plug in graph SQL migration into dev build

This commit plugs in the graph kvdb-to-sql migration for builds
containing the `test_native_sql` tag. This will allow us to perform
local tests and write itests for the migration without exposing it to
the production release build.
---
 config_builder.go         | 17 ++++++++++++++---
 config_prod.go            | 16 ++++++++++++++++
 config_test_native_sql.go | 33 +++++++++++++++++++++++++++++++++
 sqldb/migrations_dev.go   |  9 +++++++++
 4 files changed, 72 insertions(+), 3 deletions(-)

diff --git a/config_builder.go b/config_builder.go
index e47b29b7d..3c8b122a8 100644
--- a/config_builder.go
+++ b/config_builder.go
@@ -1097,7 +1097,7 @@ func (d *DefaultDatabaseBuilder) BuildDatabase(
 		// migration's version (7), it will be skipped permanently,
 		// regardless of the flag.
 		if !d.cfg.DB.SkipNativeSQLMigration {
-			migrationFn := func(tx *sqlc.Queries) error {
+			invoiceMig := func(tx *sqlc.Queries) error {
 				err := invoices.MigrateInvoicesToSQL(
 					ctx, dbs.ChanStateDB.Backend,
 					dbs.ChanStateDB, tx,
@@ -1119,11 +1119,22 @@ func (d *DefaultDatabaseBuilder) BuildDatabase(
 			// Make sure we attach the custom migration function to
 			// the correct migration version.
 			for i := 0; i < len(migrations); i++ {
-				if migrations[i].Version != invoiceMigration {
+				version := migrations[i].Version
+				if version == invoiceMigration {
+					migrations[i].MigrationFn = invoiceMig
+
 					continue
 				}
 
-				migrations[i].MigrationFn = migrationFn
+				migFn, ok := getSQLMigration(
+					ctx, version, dbs.ChanStateDB.Backend,
+					*d.cfg.ActiveNetParams.GenesisHash,
+				)
+				if !ok {
+					continue
+				}
+
+				migrations[i].MigrationFn = migFn
 			}
 		}
 
diff --git a/config_prod.go b/config_prod.go
index b480c2bb8..769d85468 100644
--- a/config_prod.go
+++ b/config_prod.go
@@ -3,9 +3,13 @@
 package lnd
 
 import (
+	"context"
+
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/sqldb"
+	"github.com/lightningnetwork/lnd/sqldb/sqlc"
 )
 
 // getGraphStore returns a graphdb.V1Store backed by a graphdb.KVStore
@@ -16,3 +20,15 @@ func (d *DefaultDatabaseBuilder) getGraphStore(_ *sqldb.BaseDB,
 
 	return graphdb.NewKVStore(kvBackend, opts...)
 }
+
+// getSQLMigration returns a migration function for the given version.
+//
+// NOTE: this is a no-op for the production build since all migrations that are
+// in production will also be in development builds, and so they are not
+// defined behind a build tag.
+func getSQLMigration(ctx context.Context, version int,
+	kvBackend kvdb.Backend,
+	chain chainhash.Hash) (func(tx *sqlc.Queries) error, bool) {
+
+	return nil, false
+}
diff --git a/config_test_native_sql.go b/config_test_native_sql.go
index 4a9469deb..dee5985a1 100644
--- a/config_test_native_sql.go
+++ b/config_test_native_sql.go
@@ -3,11 +3,15 @@
 package lnd
 
 import (
+	"context"
 	"database/sql"
+	"fmt"
 
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/sqldb"
+	"github.com/lightningnetwork/lnd/sqldb/sqlc"
 )
 
 // getGraphStore returns a graphdb.V1Store backed by a graphdb.SQLStore
@@ -29,3 +33,32 @@ func (d *DefaultDatabaseBuilder) getGraphStore(baseDB *sqldb.BaseDB,
 		graphExecutor, opts...,
 	)
 }
+
+// graphSQLMigration is the version number for the graph migration
+// that migrates the KV graph to the native SQL schema.
+const graphSQLMigration = 9
+
+// getSQLMigration returns a migration function for the given version.
+func getSQLMigration(ctx context.Context, version int,
+	kvBackend kvdb.Backend,
+	chain chainhash.Hash) (func(tx *sqlc.Queries) error, bool) {
+
+	switch version {
+	case graphSQLMigration:
+		return func(tx *sqlc.Queries) error {
+			err := graphdb.MigrateGraphToSQL(
+				ctx, kvBackend, tx, chain,
+			)
+			if err != nil {
+				return fmt.Errorf("failed to migrate graph "+
+					"to SQL: %w", err)
+			}
+
+			return nil
+		}, true
+	}
+
+	// No version was matched, so we return false to indicate that no
+	// migration is known for the given version.
+	return nil, false
+}
diff --git a/sqldb/migrations_dev.go b/sqldb/migrations_dev.go
index b8721f927..38501b58b 100644
--- a/sqldb/migrations_dev.go
+++ b/sqldb/migrations_dev.go
@@ -8,4 +8,13 @@ var migrationAdditions = []MigrationConfig{
 		Version:       8,
 		SchemaVersion: 7,
 	},
+	{
+		Name:          "kv_graph_migration",
+		Version:       9,
+		SchemaVersion: 7,
+		// A migration function may be attached to this
+		// migration to migrate KV graph to the native SQL
+		// schema. This is optional and can be disabled by the
+		// user if necessary.
+	},
 }