Function update_expr 

pub fn update_expr(
    expr: &Arc<dyn PhysicalExpr>,
    projected_exprs: &[ProjectionExpr],
    sync_with_child: bool,
) -> Result<Option<Arc<dyn PhysicalExpr>>>

The function operates in two modes:

1. When sync_with_child is true:

   The function updates the indices of expr if the expression resides in the input plan. For instance, given the expressions a@1 + b@2 and c@0 with the input schema c@2, a@0, b@1, the expressions are updated to a@0 + b@1 and c@2.

2. When sync_with_child is false:

   The function determines how the expression would be updated if a projection was placed before the plan associated with the expression. If the expression cannot be rewritten after the projection, it returns None. For example, given the expressions c@0, a@1 and b@2, and the projection with an output schema of a, c_new, then c@0 becomes c_new@1, a@1 becomes a@0, but b@2 results in None since the projection does not include b.

Errors

This function returns an error if sync_with_child is true and if any expression references an index that is out of bounds for projected_exprs. For example:

• expr is a@3
• projected_exprs is [a@0, b@1]

In this case, a@3 references index 3, which is out of bounds for projected_exprs (which has length 2).