FromQueryResult fails for PartialModel when having nested Option<Model> where the nested Model has optional fields

[ryanduan-stedi]

Description

FromQueryResult fails for PartialModel when having nested Option where the nested Model has optional fields

Steps to Reproduce

#[derive(DerivePartialModel, Debug, Clone)]
#[sea_orm(entity = "crate::definition::user::User)"]
pub struct User {
    id: Uuid,
    #[sea_orm(nested)]
    post: Option<Post>,
}

// Post Model
#[derive(Clone, Debug, PartialEq, DeriveModel, DeriveActiveModel, Eq, Serialize, Deserialize)]
pub struct Model {
    pub id: Uuid,
    pub foo: Option<String>,
}

If you try to do a left join and there are no matching user posts, and then call .into_partial_model it throws an error Missing value for column id

Expected Behavior

The query should be successful

Actual Behavior

Throws error Missing value for column id

Reproduces How Often

Always, I believe the bug is in this PR #2845
The below code always wraps the field in Option<> so you will end up with Option<Option<String>> for the Post model

let reader = quote! {
                    let #field_ident =
                        row.try_get_nullable::<Option<#field_type>>(
                            pre,
                            sea_orm::IdenStatic::as_str(
                                &<<Self as sea_orm::ModelTrait>::Entity
                                    as sea_orm::entity::EntityTrait>::Column::#column_ident
                            ).into()
                        )?;

and then when checking if the entire nested model is None, this below check is faulty because calling .is_none() on an Option<Option> value returns false when the value is
Some(None)

let all_null_check = {
            let checks: Vec<_> = izip!(field_idents, ignore_attrs)
                .filter_map(|(field_ident, &ignore)| {
                    if ignore {
                        None
                    } else {
                        Some(quote! { #field_ident.is_none() })
                    }
                })
                .collect();

            quote! { true #( && #checks )* }
        };

Workarounds

If I implement FromQueryResult myself and change the all_null_check function to properly evaluate Option<Option>, then the partial model query works properly

if true
&& id.is_none()
&& (foo.is_none() || (foo == Some(None)))
{
return Err(sea_orm::TryGetError::Null(
"All fields of nested model are null".into(),
));
}

Versions

• sea-orm v2.0.0-rc.30
• postgres 15.12

[tyt2y3]

thank for the report. can you open a PR for your proposed fix?

[ryanduan-stedi]

yes i can submit a PR this week