Re: [PATCH 11/14] tree-diff: drop list-tail argument to diff_tree_paths()

> The internals of the path diffing code, including ll_diff_tree_paths(),
> all take an extra combine_diff_path parameter which they use as the tail
> of a list of results, appending any new entries to it.
>
> The public-facing diff_tree_paths() takes the same argument, but it just
> makes the callers more awkward. They always start with a clean list, and
> have to set up a fake head struct to pass in.
>
> Let's keep the public API clean by always returning a new list. That
> keeps the fake struct as an implementation detail of tree-diff.c.