Re: [PATCH 00/17] Clean up how fetch_pack() handles the heads list

From: "Jeff King" <redacted>
Sent: Thursday, August 23, 2012 10:26 AM

On Thu, Aug 23, 2012 at 10:10:25AM +0200, mhagger@alum.mit.edu wrote:

quoted

There were various confusing things (and a couple of bugs) in the way
that fetch_pack() handled the list (nr_heads, heads) of references to
be sought from the remote:

Aside from the minor comments I made to individual patches, this all
looks good. As usual, thanks for breaking it down; I wish all series
were as easy to review as this.

quoted

I'm still suspicious about the logic related to args.fetch_all and
args.depth, but I don't think I've made anything worse.

I think the point of that is that when doing "git fetch-pack --all
--depth=1", the meaning of "--all" is changed from "all refs" to
"everything but tags".

There is a comment in \git\Documentation\technical\shallow.txt that
"- If you deepen a history, you'd want to get the tags of the
  newly stored (but older!) commits. This does not work right now."
which may be the source of this restriction. That is, how is the depth
of the tag fetching to be restricted to the requested depth count?
[assuming I've undestood the problem correctly]

It may be (?) that it is a good time to think about a 'datedepth' 
capability to bypass the current counted-depth shallow fetch that can 
cause so much trouble. With a date limited depth the relevant tags could 
also be fetched.

Which I kind of see the point of, because you don't want to grab 
ancient
tags that will be expensive. But wouldn't it make more sense to limit 
it
only to the contents of refs/heads in that case? Surely you wouldn't
want refs/notes, refs/remotes, or other hierarchies.

I suspect this code is never even run at all these days. All of the
callers inside git should actually provide a real list of refs, not
"--all". So it is really historical cruft for anybody who calls the
fetch-pack plumbing (I wonder if any third-party callers even exist;
this is such a deep part of the network infrastructure that any sane
scripts would probably just be calling fetch).

-Peff
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