Workaround for https://github.com/SeaQL/sea-orm/issues/1950

sea_orm_1950_workaround.rs

// © 2024 Theori
// Portions © 2023 Seafire Software Limited
//
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// of this software and associated documentation files (the “Software”), to
// deal in the Software without restriction, including without limitation the
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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use sea_orm::prelude::ColumnTrait;
use sea_orm::sea_query::{Alias, SeaRc, SelectExpr};
use sea_orm::{
    EntityTrait, Iden, PartialModelTrait, QuerySelect, SelectA, SelectB, SelectColumns, SelectTwo,
    SelectTwoModel, Selector,
};

struct PrependAlias<T, P> {
    inner: T,
    prefix: P,
}

impl<T, P> PrependAlias<T, P> {
    fn new(inner: T, prefix: P) -> Self {
        PrependAlias { inner, prefix }
    }

    fn into_inner(self) -> T {
        self.inner
    }
}

impl<T, P> SelectColumns for PrependAlias<T, P>
where
    T: QuerySelect,
    P: Iden,
{
    /// Partially copied from [`QuerySelect::column`].
    fn select_column<C: ColumnTrait>(mut self, col: C) -> Self {
        let alias = self.prefix.to_string() + col.as_str();
        self.inner.query().expr(SelectExpr {
            expr: col.select_as(col.into_expr()),
            alias: Some(SeaRc::new(Alias::new(alias))),
            window: None,
        });
        self
    }

    fn select_column_as<C, I>(mut self, col: C, alias: I) -> Self
    where
        C: sea_orm::IntoSimpleExpr,
        I: sea_orm::IntoIdentity,
    {
        let alias = self.prefix.to_string() + alias.into_identity().to_string().as_str();
        self.inner = self.inner.select_column_as(col, alias);
        self
    }
}

pub trait IntoPartialModelIssue1950Workaround {
    /// Perform a conversion into a [SelectTwoModel] with [PartialModel](PartialModelTrait)
    fn into_partial_model_issue1950_workaround<M, N>(self) -> Selector<SelectTwoModel<M, N>>
    where
        M: PartialModelTrait,
        N: PartialModelTrait;
}

impl<E, F> IntoPartialModelIssue1950Workaround for SelectTwo<E, F>
where
    E: EntityTrait,
    F: EntityTrait,
{
    /// Partially copied from [`SelectTwo::into_partial_model`].
    ///
    /// See <https://github.com/SeaQL/sea-orm/issues/1950>.
    fn into_partial_model_issue1950_workaround<M, N>(self) -> Selector<SelectTwoModel<M, N>>
    where
        M: PartialModelTrait,
        N: PartialModelTrait,
    {
        let select = QuerySelect::select_only(self);
        let select = M::select_cols(PrependAlias::new(select, SelectA)).into_inner();
        let select = N::select_cols(PrependAlias::new(select, SelectB)).into_inner();
        select.into_model::<M, N>()
    }
}