Function coerce_exprs_for_schema

datafusion/expr/src/expr_rewriter/mod.rs:246–281

(
    exprs: Vec<Expr>,
    src_schema: &DFSchema,
    dst_schema: &DFSchema,
)

}

fn coerce_exprs_for_schema(
    exprs: Vec<Expr>,
    src_schema: &DFSchema,
    dst_schema: &DFSchema,
) -> Result<Vec<Expr>> {
    exprs
        .into_iter()
        .enumerate()
        .map(|(idx, expr)| {
            let new_type = dst_schema.field(idx).data_type();
            if new_type != &expr.get_type(src_schema)? {
                match expr {
                    Expr::Alias(Alias { expr, name, .. }) => {
                        Ok(expr.cast_to(new_type, src_schema)?.alias(name))
                    }
                    #[expect(deprecated)]
                    Expr::Wildcard { .. } => Ok(expr),
                    _ => {
                        match expr {
                            // maintain the original name when casting a column, to avoid the
                            // tablename being added to it when not explicitly set by the query
                            // (see: https://github.com/apache/datafusion/issues/18818)
                            Expr::Column(ref column) => {
                                let name = column.name().to_owned();
                                Ok(expr.cast_to(new_type, src_schema)?.alias(name))
                            }
                            _ => Ok(expr.cast_to(new_type, src_schema)?),
                        }
                    }
                }
            } else {
                Ok(expr)
            }
        })
        .collect::<Result<_>>()
}

/// Recursively un-alias an expressions
#[inline]