From 1f634c39377f914187ae9efb1bc1bdbc94e97028 Mon Sep 17 00:00:00 2001
From: "jesse.tang" <1430482733@qq.com>
Date: Thu, 22 Sep 2022 14:50:35 +0800
Subject: [PATCH] support scan assign slice cap (#5634)

* support scan assign slice cap

* fix
---
 scan.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/scan.go b/scan.go
index 2db43160..df5a3714 100644
--- a/scan.go
+++ b/scan.go
@@ -248,7 +248,13 @@ func Scan(rows Rows, db *DB, mode ScanMode) {
 
 			if !update || reflectValue.Len() == 0 {
 				update = false
-				db.Statement.ReflectValue.Set(reflect.MakeSlice(reflectValue.Type(), 0, 20))
+				// if the slice cap is externally initialized, the externally initialized slice is directly used here
+				if reflectValue.Cap() == 0 {
+					db.Statement.ReflectValue.Set(reflect.MakeSlice(reflectValue.Type(), 0, 20))
+				} else {
+					reflectValue.SetLen(0)
+					db.Statement.ReflectValue.Set(reflectValue)
+				}
 			}
 
 			for initialized || rows.Next() {