find_with_related does not return records with no related entity. It just records that have more than one related entities.

[hamedai]

1. Create two entities named A and B. A has many Bs. So, B is A's related entity.
2. Create an instance of A that has no B.
3. Now try to retrieve this instance with the following query:

a_model::Entity::find().filter(some filters)
                .find_with_related(b_model::Entity)
                .all(db)
                .await?
                .first()
                .map(|t| t.to_owned())
                .into()

Expected Behavior

return A with an empty list of Bs

Actual Behavior

no A has been returned

Reproduces How Often

Always

Workarounds

Reproducible Example

Versions

[tyt2y3]

It sounds like left join vs inner join. However find_with_related always calls left join. Can you provide a reproducible example?

[hamedai]

I have checked the generated SQL. It is using left join. and by looking at the logs, it seems that the result has one response.
The example:
This a public repository I was working on: https://github.com/bkonkle/rust-example-caster-api
users and role_grants have such a relation, they are located in lib/domains.
In the graphQL router when it is checking the credential by this code:

            .get_by_username(username, &true)
            .await
            .unwrap_or(None)

It will try to use the problematic feature I mentioned before.
/lib/domains/users/service.rs:get_by_username@line 80

            query
                .find_with_related(role_grant_model::Entity)
                .all(&*self.db)
                .await?
                .first()
                .map(|t| t.to_owned())
                .into()

Note that the issue does not appear on version 11.*, it is just on version 12.0.1.

[tyt2y3]

Thank you for reporting. I think I have a clue now. You pointed out a regression.

[hamedai]

No problem!
I'm looking forward to the next version!

[tyt2y3]

Please try 0.12.2

[tyt2y3]

@hamedai appreciate if you can let me know if it's good

[hamedai]

Thanks, Chris!
I have tested it and it works fine now.

[tyt2y3]

Thank you. Note to self: we'd need to add more test cases.