Re: [PATCH] repack: Add options to preserve and prune old pack files

> 
> I am not sure if I understand your design.  Your model looks to me
> like there are two modes of operation.  #1 uses "--preserve-old" and
> sends old ones to purgatory instead of removing them and #2 uses
> "--prune-preserved" to remove all the ones in the purgatory
> immediately.  A few things that come to my mind immediately:
> 
>  * When "--prune-preseved" is used, it removes both ancient ones and
>    more recent ones indiscriminately.  Would it make more sense to
>    "expire" only the older ones while keeping the more recent ones?
> 
>  * It appears that the main reason you would want --prune-preserved
>    in this design is after running with "--preserve-old" number of
>    times, you want to remove really old ones that have accumulated,
>    and I would imagine that at that point of time, you are only
>    interested in repack, but the code structure tells me that this
>    will force the users to first run a repack before pruning.
> 
> I suspect that a design that is simpler to explain to the users may
> be to add a command line option "--preserve-pruned=<expiration>" and
> a matching configuration variable repack.preservePruned, which
> defaults to "immediate" (i.e. no preserving), and
> 
>  - When the value of preserve_pruned is not "immediate", use
>    preserve_pack() instead of unlink();
> 
>  - At the end, find preserved packs that are older than the value in
>    preserve_pruned and unlink() them.
> 
> It also may make sense to add another command line option
> "--prune-preserved-packs-only" (without matching configuration
> variable) that _ONLY_ does the "find older preserved packs and
> unlink them" part, without doing any repack.