Re: [PATCH v2] diff-tree: fix crash when used with --remerge-diff

Junio C Hamano [off-list ref] writes:

but I have to wonder if we do even better in a future follow-up
patch.

"if we do" -> "if we can do".

So wouldn't it work well if we

 (1) at the beginning of do_remerge_diff(), only once for a rev_info
     structure:
   (1-a) lazily do the "object directory rotation"
   (1-b) set up an atexit handler to clear the temporary object
         store

An atexit handler may not be enough, when a program wants to start
creating a real object after we did a remerge-diff but before
exiting. So we'd probably need to allow an explicit "ok, we are
done" clean-up call for such a program, too.

And the atexit handler can call the same clean-up function if the
program hasn't called it explicitly.  For logically read-only
operations like diff-tree, they do not have to worry about rotating
the real object store back to the primary status as soon as
possible.