Function extend_reach_table 

pub fn extend_reach_table(
    table: &ReachTable,
    graph: &OrdGraph,
    facts: &ObjectFacts<'_>,
    new_rows: &[u32],
    policy: ReachPolicy,
) -> ReachTable

Extend a table after a push: entries for the new tips (and a sample of the other new commits), each computed by the bounded walk down to the entries that already exist. Nothing already in the table is touched or recomputed; the cost is the pushed commits’ trees, whatever the repository’s size. new_rows must be in parents-before-children order (the caller takes them off the generation-ordered graph).