Re: [PATCH v3 00/18] Sparse checkout improvements -- improved sparsity updating

> This series provides a replacement for the sparsity updating in
> sparse-checkout that is based on the logic from git read-tree -mu HEAD. The
> most important bit is patch 9 and its lengthy commit message explaining the
> current state and rationale for most the series, though patches 16 and 17
> have additional related directions and rationale for the series. Those three
> patches are the most important to review.
> 
> Changes since v2:
> 
>  * addressed Stolee's cleanups and added his Reviewed-by to the series
>    (hopefully the next two changes don't invalidate that)

>  * added a test for the new 'reapply' subcommand (noticed it was missing
>    with Stolee's test coverage report)
>  * fix a minor issue with two of the other tests I modified -- when I'm
>    grepping through stderr for a command, I need to make sure to actually
>    record stderr from that command (otherwise my grep is looking through the
>    stderr of a previous command that was recorded). Also, since I messed
>    this up, I added one or two more sanity checks while I was at it.