Function coerce_plan_expr_for_schema

datafusion/expr/src/expr_rewriter/mod.rs:221–244

Returns plan with expressions coerced to types compatible with schema types

(
    plan: LogicalPlan,
    schema: &DFSchema,
)

/// Returns plan with expressions coerced to types compatible with
/// schema types
pub fn coerce_plan_expr_for_schema(
    plan: LogicalPlan,
    schema: &DFSchema,
) -> Result<LogicalPlan> {
    match plan {
        // special case Projection to avoid adding multiple projections
        LogicalPlan::Projection(Projection { expr, input, .. }) => {
            let new_exprs = coerce_exprs_for_schema(expr, input.schema(), schema)?;
            let projection = Projection::try_new(new_exprs, input)?;
            Ok(LogicalPlan::Projection(projection))
        }
        _ => {
            let exprs: Vec<Expr> = plan.schema().iter().map(Expr::from).collect();
            let new_exprs = coerce_exprs_for_schema(exprs, plan.schema(), schema)?;
            let add_project = new_exprs.iter().any(|expr| expr.try_as_col().is_none());
            if add_project {
                let projection = Projection::try_new(new_exprs, Arc::new(plan))?;
                Ok(LogicalPlan::Projection(projection))
            } else {
                Ok(plan)
            }
        }
    }
}

fn coerce_exprs_for_schema(
    exprs: Vec<Expr>,