Re: [PATCH v2] fetch-pack: optionally save packs to disk

>> What is the problem with the current fetch-pack implementation? Does
>> it remove a bogus packfile after download? Does it abort during
>> download when it detects a broken packfile? Does --keep not do what
>> you need?
>
> Doesn't the incoming data still go through the fattening process,
> though?  You will not be able to inspect the byte-for-byte identical
> stream that came out of the server end whose packfile generation
> logic is suspect.
>
> For the purpose of debugging your own new server implementation, it
> might be a better approach to capture the pack as it comes out at
> the server end, instead of doing it at the fetch-pack end as it
> comes in. But the approach to add this "dump" at the fetch-pack side
> is that it gives us a tool to diagnose problems that come from
> broken server (re)implementations by other people we cannot debug,
> i.e. "you are spewing this corrupt pack against this request; here
> is a dump we took to help you go fix your server".

>
>> Instead of your approach (which forks off tee to dump a copy of the
>> packfile), would it not be simpler to add an option --debug-pack
>> (probably not the best name) that skips the cleanup step when a broken
>> packfile is detected and prints the name of the downloaded packfile?
>
> As long as we need to debug a thin pack that comes from the other
> end, that approach is not sufficient, I am afraid.
>
> I anticipated that you'd have problem with its use of "tee".  It
> probably can do this internally with async interface, perhaps,
> instead?