[5.7] Fix self-referencing HasManyThrough existence queries

[staudenmeir]

Existence queries of self-referencing HasManyThrough relationships are incorrect:

class User extends Model {
    public function teamMates() {
        return $this->hasManyThrough(self::class, Team::class, 'owner_id');
    }
}

User::has('teamMates')->get();

# expected
select * from `users` where exists (
  select * from `users` as `laravel_reserved_0`
  inner join `teams` on `teams`.`id` = `laravel_reserved_0`.`team_id`
  where `users`.`id` = `teams`.`owner_id`
)

# actual
select * from `users` where exists (
  select * from `users` as `laravel_reserved_0`
  inner join `teams` on `teams`.`id` = `laravel_reserved_0`.`id`
  where `users`.`id` = `teams`.`owner_id`                    ^^
)

The tests didn't catch this because all the models have the same ids 1 and 2.

[laurencei]

Your on fire 🔥

[ankurk91]

Hey @staudenmeir
Huge thanks for what you are doing for Laravel. 👍

[taylorotwell]

Thanks

[aaronkorn]

Thanks you, that fixed I problem I was having.

Can you take a look at this Belongs To Relationship?
Laravel is creating a subcategory_id instead of a sub_category_id.

Illuminate\Database\QueryException : SQLSTATE[HY000]: General error: 1 no such column: subcategory_id (SQL: update "transactions" set "subcategory_id" = 1, "updated_at" = 2018-12-08 23:50:57 where "id" = 1)

This is the setup

Transaction Table
$table->increments('id');
$table->timestamps();
$table->unsignedInteger('sub_category_id');
MODEL: return $this->belongsTo(SubCategory::class);

SubCategory Table
$table->increments('id');
$table->timestamps();
MODEL: return $this->hasMany(Transaction::class);

class TransactionsTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        //
        factory(App\Transaction::class, 5)
        ->create()
        ->each(function ($transaction) {
            $subcategory = factory(App\SubCategory::class)->create();
            $transaction->subcategory()->associate($subcategory);
            $transaction->save();
        });
    }
}

Of course, I can change it to subcategory_id but I have other tables that follow the '_' naming convention and would break some of my hasManyThrough Relationships.

[driesvints]

@aaronkorn please open an issue for this instead. Thanks!