Re: [PATCH 01/13] commit-graph: require resolved packfile paths for `stdin_packs`

Patrick Steinhardt [off-list ref] writes:

Users can ask git-commit-graph(1) to write a commit graph specifically
for a set of packfiles via the "--stdin-packs" option. Those users are
expected to pass in relative paths, and those eventually get resolved in
`fill_oids_from_packs()`. This ties the logic in "commit-graph.c" to the
specific object database source.

Refactor the logic to instead require the caller to pass in resolved
packfiles to untangle that dependency.

Nit: the changes look good, what I'm missing is 'why' are we doing this
change.

[snip]