Re: capturing the packfile from git-upload-pack

[Jeff King <peff@peff.net>]

On Fri, Apr 15, 2011 at 10:46:28AM -0700, Junio C Hamano wrote:

> Shawn Pearce <spearce@spearce.org> writes:
> 
> > On Thu, Apr 14, 2011 at 23:22, madmarcos <fru574@my.utsa.edu> wrote:
> >> is there a git command that can capture in a separate file the packfile that
> >> is generated and transmitted from a "want"ed branch during the
> >> git-upload-pack command? I need a good sample to study.
> >
> > No.
> >
> > But you can create an input file yourself, the pkt-line format is
> > pretty simple. Pipe the input to git-upload-pack, and it will spit
> > back the response. :-)
> 
> If you are running 1.7.5-rc0 or newer, GIT_TRACE_PACKET may also be of
> help.

Sadly, no. I punted on outputting the actual pack since it is big and
binary, and I was only interested in the ref negotiation. My eventual
plan was that you could do:

  GIT_TRACE_PACKET=2 GIT_TRACE_PACKET_PACK=/tmp/foo.pack \
    git clone ...

and get the ref negotiation on stderr, and the pack dumped in a file.
However, there is one stumbling block: the packet tracing happens at a
very low level, and doesn't know if we are doing sideband-demuxing or
not. And it would need to know to that to put the proper data in the
packfile.

It may just be a matter of implementing the packfile tracing at a
slightly different layer (where we have already demuxed), but I haven't
looked closely at it.

-Peff