[EntityLoader] `EntityLoader::load()::with()` does not work for `self_ref` self references.

[leuchthelp]

Description

I believe that EntityLoader::load()::with() does not work when trying to additionally select self referencing relations. Below is a hopefully working simple setup which I adapted from my existing project here. It should showcase the issue, but I haven't fully implemented it within a test project.

Steps to Reproduce

human.rs

use sea_orm::entity::prelude::*;

#[sea_orm::model]
#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
#[sea_orm(table_name = "humans")]
pub struct Model {
    #[sea_orm(primary_key)]
    id: i32,
   #[sea_orm(has_many)]
    pub hats: HasMany<super::hats::Entity>,
    #[sea_orm(
        self_ref,
        via = "jt_parent_to_child",
        from = "Humans",
        to = "Child"
    )]
    pub children: HasMany<Entity>,
    #[sea_orm(self_ref, via = "jt_parent_to_child", reverse)]
    pub parents: HasMany<Entity>,
}

impl ActiveModelBehavior for ActiveModel {}

jt_parent_child.rs

use sea_orm::entity::prelude::*;

#[sea_orm::model]
#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
#[sea_orm(table_name = "jt_parent_to_child")]
pub struct Model {
    #[sea_orm(primary_key, auto_increment = false)]
    pub parent_id: i32,
    #[sea_orm(primary_key, auto_increment = false)]
    pub child_id: i32,
    #[sea_orm(belongs_to, from = "parent_id", to = "id")]
    pub parent: BelongsTo<super::humans::Entity>,
    #[sea_orm(belongs_to, relation_enum = "Child", from = "child_id", to = "id")]
    pub child: BelongsTo<super::humans::Entity>,
}

impl ActiveModelBehavior for ActiveModel {}

hats.rs

use sea_orm::entity::prelude::*;

#[sea_orm::model]
#[derive(Default, Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
#[sea_orm(table_name = "hats")]
pub struct Model {
    #[sea_orm(primary_key)]
    id: i32,
    pub human_id: Option<i32>,
    #[sea_orm(belongs_to, from = "human_id", to = "id")]
    pub parent: BelongsTo<Option<super::humans::Entity>>,
}

Expected Behavior

This should work. However, since there currently is no mechanism to specifically identify the specific self _ref to select you would have to input .with(humans::Entity).

human::Entity::load()
            .filter_by_d(1)
            .with(hats::Entity)
            .with(/*some kind of mechanism to identify specific self ref*/)
            .one(db
            .await

Actual Behavior

This then fails with:

error[E0277]: the trait bound `entity::Humans: entity::humans::EntityLoaderWithParam` is not satisfied
   --> humans.rs:176:19
    |
176 |             .with(humans::Entity)
    |              ---- ^^^^^^^^^^^^^^^^^^^ the trait `Related<entity::Humans>` is not implemented for `entity::Humans`
    |              |
    |              required by a bound introduced by this call
    |
help: `entity::Humans` implements trait `Related<R>`
   --> some.rs:37:1
    |
 37 | #[sea_orm::model]
    | ^^^^^^^^^^^^^^^^^
    | |
    | `Related<entity::Hats>`
    = note: required for `entity::Humans` to implement `entity::humans::EntityLoaderWithParam`
note: required by a bound in `entity::humans::EntityLoader::with`
   --> humans.rs:37:1
    |
 37 | #[sea_orm::model]
    | ^^^^^^^^^^^^^^^^^ required by this bound in `EntityLoader::with`
    = note: this error originates in the derive macro `DeriveModelEx` (in Nightly builds, run with -Z macro-backtrace for more info)

Reproduces How Often

always

Workarounds

current none known

Versions

❯ cargo tree | grep sea-
│   │   ├── sea-orm v2.0.2
│   │   │   ├── sea-orm-macros v2.0.2 (proc-macro)
│   │   │   │   ├── sea-bae v0.2.2 (proc-macro)
│   │   │   ├── sea-query v1.0.2
│   │   │   │   ├── sea-query-derive v1.0.0 (proc-macro)
│   │   │   ├── sea-query-sqlx v0.9.1
│   │   │   │   ├── sea-query v1.0.2 (*)
│   │   │   ├── sea-schema v0.18.1
│   │   │   │   ├── sea-query v1.0.2 (*)
│   │   │   │   ├── sea-query-sqlx v0.9.1 (*)
│   │   │   │   ├── sea-schema-derive v0.3.0 (proc-macro)
│   │   ├── sea-query v1.0.2 (*)
├── sea-orm v2.0.2 (*)

[leuchthelp]

I've finally found the Complex Relations page had been updated with some examples on how to select self_ref models.

Sorry for overlooking these.

There I found I could select .with(jt_parent_to_child::Entity) to, I believe, get children while .with(jt_parent_to_child::Entity::REVERSE) is used to select the model which is marked as #[sea_orm(self_ref, via = "jt_parent_to_child", reverse)] which is parents in this case.

I'm still tested if that is how it works, but I believe that is how it is supposed to work. This example is also not explicitly covered, I just derived it from the existing ones.

[leuchthelp]

There I found I could select .with(jt_parent_to_child::Entity) to, I believe, get children while .with(jt_parent_to_child::Entity::REVERSE) is used to select the model which is marked as #[sea_orm(self_ref, via = "jt_parent_to_child", reverse)] which is parents in this case.

I was correct with my assumption here.

So it might already work, just isn't that ergonomic to use - at least for me.

Maybe an extra example would help. Regardless the bug tag can probably be removed or the issue could be closed entirely, depending on if you want to keep it up for possible inspiration for improvement of the API.