From a3cc6c6088c1e2aa8cbd174f4714e7fc6d0acd59 Mon Sep 17 00:00:00 2001
From: Stephano George <huohuo5230@gmail.com>
Date: Fri, 30 Sep 2022 17:18:42 +0800
Subject: [PATCH] Fix: wrong value when Find with Join with same column name,
 close #5723, #5711

---
 scan.go             | 31 ++++++++++++++-----------------
 tests/go.mod        |  4 ++--
 tests/joins_test.go | 31 +++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 19 deletions(-)

diff --git a/scan.go b/scan.go
index 70cd4284..3a753dca 100644
--- a/scan.go
+++ b/scan.go
@@ -163,11 +163,10 @@ func Scan(rows Rows, db *DB, mode ScanMode) {
 		}
 	default:
 		var (
-			fields             = make([]*schema.Field, len(columns))
-			selectedColumnsMap = make(map[string]int, len(columns))
-			joinFields         [][2]*schema.Field
-			sch                = db.Statement.Schema
-			reflectValue       = db.Statement.ReflectValue
+			fields       = make([]*schema.Field, len(columns))
+			joinFields   [][2]*schema.Field
+			sch          = db.Statement.Schema
+			reflectValue = db.Statement.ReflectValue
 		)
 
 		if reflectValue.Kind() == reflect.Interface {
@@ -200,26 +199,24 @@ func Scan(rows Rows, db *DB, mode ScanMode) {
 
 			// Not Pluck
 			if sch != nil {
-				schFieldsCount := len(sch.Fields)
+				matchedFieldCount := make(map[string]int, len(columns))
 				for idx, column := range columns {
 					if field := sch.LookUpField(column); field != nil && field.Readable {
-						if curIndex, ok := selectedColumnsMap[column]; ok {
-							fields[idx] = field // handle duplicate fields
-							offset := curIndex + 1
-							// handle sch inconsistent with database
-							// like Raw(`...`).Scan
-							if schFieldsCount > offset {
-								for fieldIndex, selectField := range sch.Fields[offset:] {
-									if selectField.DBName == column && selectField.Readable {
-										selectedColumnsMap[column] = curIndex + fieldIndex + 1
+						fields[idx] = field
+						if count, ok := matchedFieldCount[column]; ok {
+							// handle duplicate fields
+							for _, selectField := range sch.Fields {
+								if selectField.DBName == column && selectField.Readable {
+									if count == 0 {
+										matchedFieldCount[column]++
 										fields[idx] = selectField
 										break
 									}
+									count--
 								}
 							}
 						} else {
-							fields[idx] = field
-							selectedColumnsMap[column] = idx
+							matchedFieldCount[column] = 1
 						}
 					} else if names := strings.Split(column, "__"); len(names) > 1 {
 						if rel, ok := sch.Relationships.Relations[names[0]]; ok {
diff --git a/tests/go.mod b/tests/go.mod
index ebebabc0..c1e1e0ce 100644
--- a/tests/go.mod
+++ b/tests/go.mod
@@ -9,12 +9,12 @@ require (
 	github.com/jinzhu/now v1.1.5
 	github.com/lib/pq v1.10.7
 	github.com/mattn/go-sqlite3 v1.14.15 // indirect
-	golang.org/x/crypto v0.0.0-20220919173607-35f4265a4bc0 // indirect
+	golang.org/x/crypto v0.0.0-20220926161630-eccd6366d1be // indirect
 	gorm.io/driver/mysql v1.3.6
 	gorm.io/driver/postgres v1.3.10
 	gorm.io/driver/sqlite v1.3.6
 	gorm.io/driver/sqlserver v1.3.2
-	gorm.io/gorm v1.23.9
+	gorm.io/gorm v1.23.10
 )
 
 replace gorm.io/gorm => ../
diff --git a/tests/joins_test.go b/tests/joins_test.go
index 4908e5ba..7519db82 100644
--- a/tests/joins_test.go
+++ b/tests/joins_test.go
@@ -229,3 +229,34 @@ func TestJoinWithSoftDeleted(t *testing.T) {
 		t.Fatalf("joins NamedPet and Account should not empty:%v", user2)
 	}
 }
+
+func TestJoinWithSameColumnName(t *testing.T) {
+	user := GetUser("TestJoinWithSameColumnName", Config{
+		Languages: 1,
+		Pets:      1,
+	})
+	DB.Create(user)
+	type UserSpeak struct {
+		UserID       uint
+		LanguageCode string
+	}
+	type Result struct {
+		User
+		UserSpeak
+		Language
+		Pet
+	}
+
+	results := make([]Result, 0, 1)
+	DB.Select("users.*, user_speaks.*,  languages.*, pets.*").Table("users").Joins("JOIN user_speaks ON user_speaks.user_id = users.id").
+		Joins("JOIN languages ON languages.code = user_speaks.language_code").
+		Joins("LEFT OUTER JOIN pets ON pets.user_id = users.id").Find(&results)
+
+	if len(results) == 0 {
+		t.Fatalf("no record find")
+	} else if results[0].Pet.UserID == nil || *(results[0].Pet.UserID) != user.ID {
+		t.Fatalf("wrong user id in pet")
+	} else if results[0].Pet.Name != user.Pets[0].Name {
+		t.Fatalf("wrong pet name")
+	}
+}