fix: duplicate column scan (#5369)

* fix: duplicate column scan

* fix: dup filed in inconsistent schema and database

* chore[ci skip]: gofumpt style

* chore[ci skip]: fix typo

scan.go

@@ -193,16 +193,23 @@ func Scan(rows Rows, db *DB, mode ScanMode) {
 
 			// Not Pluck
 			if sch != nil {
+				schFieldsCount := len(sch.Fields)
 				for idx, column := range columns {
 					if field := sch.LookUpField(column); field != nil && field.Readable {
 						if curIndex, ok := selectedColumnsMap[column]; ok {
-							for fieldIndex, selectField := range sch.Fields[curIndex+1:] {
+							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] = selectField
 										break
 									}
 								}
+							}
 						} else {
 							fields[idx] = field
 							selectedColumnsMap[column] = idx

tests/scan_test.go

@@ -214,4 +214,29 @@ func TestScanToEmbedded(t *testing.T) {
 	if !addressMatched {
 		t.Errorf("Failed, no address matched")
 	}
+
+	personDupField := Person{ID: person1.ID}
+	if err := DB.Select("people.id, people.*").
+		First(&personDupField).Error; err != nil {
+		t.Errorf("Failed to run join query, got error: %v", err)
+	}
+	AssertEqual(t, person1, personDupField)
+
+	user := User{
+		Name: "TestScanToEmbedded_1",
+		Manager: &User{
+			Name:    "TestScanToEmbedded_1_m1",
+			Manager: &User{Name: "TestScanToEmbedded_1_m1_m1"},
+		},
+	}
+	DB.Create(&user)
+
+	type UserScan struct {
+		ID        uint
+		Name      string
+		ManagerID *uint
+	}
+	var user2 UserScan
+	err := DB.Raw("SELECT * FROM users INNER JOIN users Manager ON users.manager_id = Manager.id WHERE users.id = ?", user.ID).Scan(&user2).Error
+	AssertEqual(t, err, nil)
 }