fix: has many relation with driver.Valuer

internal/dbtest/db_test.go

@@ -279,6 +279,7 @@ func TestDB(t *testing.T) {
 		{testWithForeignKeys},
 		{testWithForeignKeysHasMany},
 		{testWithPointerForeignKeysHasMany},
+		{testWithPointerForeignKeysHasManyWithDriverValuer},
 		{testInterfaceAny},
 		{testInterfaceJSON},
 		{testScanRawMessage},
@@ -1172,6 +1173,60 @@ func testWithPointerForeignKeysHasMany(t *testing.T, db *bun.DB) {
 	require.Len(t, deck.Users, 2)
 }
 
+func testWithPointerForeignKeysHasManyWithDriverValuer(t *testing.T, db *bun.DB) {
+	type User struct {
+		ID     *int `bun:",pk"`
+		DeckID sql.NullInt64
+		Name   string
+	}
+	type Deck struct {
+		ID    int64   `bun:",pk"`
+		Users []*User `bun:"rel:has-many,join:id=deck_id"`
+	}
+
+	if db.Dialect().Name() == dialect.SQLite {
+		_, err := db.Exec("PRAGMA foreign_keys = ON;")
+		require.NoError(t, err)
+	}
+
+	for _, model := range []interface{}{(*Deck)(nil), (*User)(nil)} {
+		_, err := db.NewDropTable().Model(model).IfExists().Exec(ctx)
+		require.NoError(t, err)
+	}
+
+	mustResetModel(t, ctx, db, (*User)(nil))
+	_, err := db.NewCreateTable().
+		Model((*Deck)(nil)).
+		IfNotExists().
+		WithForeignKeys().
+		Exec(ctx)
+	require.NoError(t, err)
+	mustDropTableOnCleanup(t, ctx, db, (*Deck)(nil))
+
+	deckID := int64(1)
+	deck := Deck{ID: deckID}
+	_, err = db.NewInsert().Model(&deck).Exec(ctx)
+	require.NoError(t, err)
+
+	userID1 := 1
+	userID2 := 2
+	users := []*User{
+		{ID: &userID1, DeckID: sql.NullInt64{Int64: deckID, Valid: true}, Name: "user 1"},
+		{ID: &userID2, DeckID: sql.NullInt64{Int64: deckID, Valid: true}, Name: "user 2"},
+	}
+
+	res, err := db.NewInsert().Model(&users).Exec(ctx)
+	require.NoError(t, err)
+
+	affected, err := res.RowsAffected()
+	require.NoError(t, err)
+	require.Equal(t, int64(2), affected)
+
+	err = db.NewSelect().Model(&deck).Relation("Users").Scan(ctx)
+	require.NoError(t, err)
+	require.Len(t, deck.Users, 2)
+}
+
 func testInterfaceAny(t *testing.T, db *bun.DB) {
 	switch db.Dialect().Name() {
 	case dialect.MySQL:

model_table_has_many.go

@@ -3,6 +3,7 @@ package bun
 import (
 	"context"
 	"database/sql"
+	"database/sql/driver"
 	"fmt"
 	"reflect"
 
@@ -152,7 +153,13 @@ func modelKey(key []interface{}, strct reflect.Value, fields []*schema.Field) []
 // The value is then used as a map key.
 func indirectFieldValue(field reflect.Value) interface{} {
 	if field.Kind() != reflect.Ptr {
-		return field.Interface()
+		i := field.Interface()
+		if valuer, ok := i.(driver.Valuer); ok {
+			if v, err := valuer.Value(); err == nil {
+				return v
+			}
+		}
+		return i
 	}
 	if field.IsNil() {
 		return nil