Method extract_non_errors_from_expr_mut

src/expr/src/linear.rs:374–400

Removes an error-free MapFilterProject from the root of the expression. The expression will be modified to extract maps, filters, and projects from the root of the expression, which will be returned as `Self`. The extraction will halt if a Map or Filter containing a literal error is reached. Otherwise, the method will return an identity operator, and the expression will remain unchanged. This me

(expr: &mut MirRelationExpr)

    /// This method is meant to be used during optimization, where it is
    /// necessary to avoid moving around maps and filters with errors.
    pub fn extract_non_errors_from_expr_mut(expr: &mut MirRelationExpr) -> Self {
        match expr {
            MirRelationExpr::Map { input, scalars }
                if scalars.iter().all(|s| !s.is_literal_err()) =>
            {
                let mfp =
                    Self::extract_non_errors_from_expr_mut(input).map(scalars.iter().cloned());
                *expr = input.take_dangerous();
                mfp
            }
            MirRelationExpr::Filter { input, predicates }
                if predicates.iter().all(|p| !p.is_literal_err()) =>
            {
                let mfp = Self::extract_non_errors_from_expr_mut(input)
                    .filter(predicates.iter().cloned());
                *expr = input.take_dangerous();
                mfp
            }
            MirRelationExpr::Project { input, outputs } => {
                let mfp =
                    Self::extract_non_errors_from_expr_mut(input).project(outputs.iter().cloned());
                *expr = input.take_dangerous();
                mfp
            }
            x => Self::new(x.arity()),
        }
    }
}

impl<E: OptimizableExpr> MapFilterProject<E> {