Function assert_valid_optimization

datafusion/optimizer/src/optimizer.rs:502–511

These are invariants which should hold true before and after [`LogicalPlan`] optimization. This differs from [`LogicalPlan::check_invariants`], which addresses if a singular LogicalPlan is valid. Instead, this address if the optimization was valid based upon permitted changes.

(
    plan: &LogicalPlan,
    prev_schema: &Arc<DFSchema>,
)

/// This differs from [`LogicalPlan::check_invariants`], which addresses if a singular
/// LogicalPlan is valid. Instead, this address if the optimization was valid based upon permitted changes.
fn assert_valid_optimization(
    plan: &LogicalPlan,
    prev_schema: &Arc<DFSchema>,
) -> Result<()> {
    // verify invariant: optimizer passes should not change the schema if the schema can't be cast from the previous schema.
    // Refer to <https://datafusion.apache.org/contributor-guide/specification/invariants.html#logical-schema-is-invariant-under-logical-optimization>
    assert_expected_schema(prev_schema, plan)?;

    Ok(())
}

#[cfg(test)]
mod tests {