Re: [PATCH 1/3] t7700: add failing --path-walk test

>
> From: Derrick Stolee <stolee@gmail.com>
>
> Users reported an issue where objects were missing from their local
> enlistments after a full repack using 'git repack -adf --path-walk'.

> The root cause is that certain objects existed in the index and had no
> second versions. These objects are usually blobs, though trees can be
> included if a cache-tree exists. The issue is that the revision walk
> adds these objects to the "pending" list and the path-walk API forgets
> to mark the lists it creates at this point as "maybe_interesting". If
> these paths only ever have a single version in the history of the repo
> (including the current staged version) then the parent directory never
> tries to add a new object to the list and mark the list as
> "maybe_interesting". Thus, when walking the list later, the group is
> skipped as it is expected that no objects are interesting. This happens
> even when there are actually no UNINTERESTING objects at all! This is
> based on the optimization enabled by the pack.useSparse=true config
> option, which is the default.
>
> Thus, we create a test case that demonstrates the many cases of this
> issue for reproducibility:
>
>  1. File a/b/c has only one committed version.
>  2. Files a/i and x/y only exists as staged changes.