From 983443da0f8c9fea72422decf6c65e73395269cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=89=93=E8=B0=B7=E6=9C=BA?= <wule61@live.com>
Date: Tue, 1 Nov 2022 19:37:29 +0800
Subject: [PATCH] Modify ToSQL function signature

add error return value
---
 gorm.go | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/gorm.go b/gorm.go
index 589fc4ff..0f640ddb 100644
--- a/gorm.go
+++ b/gorm.go
@@ -464,15 +464,19 @@ func (db *DB) Use(plugin Plugin) error {
 
 // ToSQL for generate SQL string.
 //
-// db.ToSQL(func(tx *gorm.DB) *gorm.DB {
+// db.ToSQL(func(tx *gorm.DB) (*gorm.DB, error) {
 // 		return tx.Model(&User{}).Where(&User{Name: "foo", Age: 20})
 // 			.Limit(10).Offset(5)
 //			.Order("name ASC")
-//			.First(&User{})
+//			.First(&User{}), nil
 // })
-func (db *DB) ToSQL(queryFn func(tx *DB) *DB) string {
-	tx := queryFn(db.Session(&Session{DryRun: true, SkipDefaultTransaction: true}))
+func (db *DB) ToSQL(queryFn func(tx *DB) (*DB, error)) (string, error) {
+	tx, err := queryFn(db.Session(&Session{DryRun: true, SkipDefaultTransaction: true}))
+	if err != nil {
+		return "", err
+	}
+	
 	stmt := tx.Statement
 
-	return db.Dialector.Explain(stmt.SQL.String(), stmt.Vars...)
+	return db.Dialector.Explain(stmt.SQL.String(), stmt.Vars...), nil
 }