Unscoped "Preload All" not working

[antoninbas]

GORM Playground Link

go-gorm/playground#397

Description

I want to use Unscoped with a "preload all" to load all associations, but it is not working as expected.

The following fails to load associations which have been soft-deleted:

DB.Preload(clause.Associations, func(db *gorm.DB) *gorm.DB { return db.Unscoped() }).Find(&user, id)

While the following (load specific associations by name) succeeds:

DB.Preload("Company", func(db *gorm.DB) *gorm.DB { return db.Unscoped() }).Preload("Manager", func(db *gorm.DB) *gorm.DB { return db.Unscoped() }).Find(&user, id)

Notice the differences in SQL queries:

=== RUN   TestGORM/Distinct_preloads

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:45
[0.283ms] [rows:1] SELECT * FROM `companies` WHERE `companies`.`id` = 1

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:45
[0.276ms] [rows:1] SELECT * FROM `users` WHERE `users`.`id` = 1

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:45
[1.571ms] [rows:1] SELECT * FROM `users` WHERE `users`.`id` = 2 AND `users`.`deleted_at` IS NULL
=== RUN   TestGORM/Preload_all

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.149ms] [rows:0] SELECT * FROM `accounts` WHERE `accounts`.`user_id` = 2 AND `accounts`.`deleted_at` IS NULL

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.240ms] [rows:0] SELECT * FROM `companies` WHERE `companies`.`id` = 1 AND `companies`.`deleted_at` IS NULL

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.127ms] [rows:0] SELECT * FROM `user_friends` WHERE `user_friends`.`user_id` = 2

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.120ms] [rows:0] SELECT * FROM `user_speaks` WHERE `user_speaks`.`user_id` = 2

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.119ms] [rows:0] SELECT * FROM `users` WHERE `users`.`id` = 1 AND `users`.`deleted_at` IS NULL

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.119ms] [rows:0] SELECT * FROM `pets` WHERE `pets`.`user_id` = 2 AND `pets`.`deleted_at` IS NULL

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.121ms] [rows:0] SELECT * FROM `users` WHERE `users`.`manager_id` = 2 AND `users`.`deleted_at` IS NULL

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[0.134ms] [rows:0] SELECT * FROM `toys` WHERE `owner_type` = "users" AND `toys`.`owner_id` = 2 AND `toys`.`deleted_at` IS NULL

2021/11/04 12:55:47 /Users/abas/vmware/gorm-playground/main_test.go:62
[2.554ms] [rows:1] SELECT * FROM `users` WHERE `users`.`id` = 2 AND `users`.`deleted_at` IS NULL
    main_test.go:66: Wrong company name
    main_test.go:69: Wrong manager

The Unscoped is basically ignored for the "Preload All" case, with deleted_at IS NULL` being added to queries.