Re: [PATCH 04/10] commit-graph: move slab-clearing to close_commit_graph()

> When closing and freeing a commit-graph, the main entry point is
> close_commit_graph(), which then uses close_commit_graph_one() to
> recurse through the base_graph links and free each one.
>
> Commit 957ba814bf (commit-graph: when closing the graph, also release
> the slab, 2021-09-08) put the call to clear the slab into the recursive
> function, but this is pointless: there's only a single global slab
> variable. It works OK in practice because clearing the slab is
> idempotent, but it makes the code harder to reason about and refactor.