If you try to push into an empty repository with no ref arguments to
git push, it doesn't do anything and doesn't say anything. This adds a
warning when send-pack isn't going to push anything, so you don't
assume that it silently did what you wanted.
Signed-off-by: NDaniel Barkalow <barkalow@iabervon.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

These are whole-tree operations and there is not much point
making them operable from within a subdirectory, but it is easy
to do so, and using setup_git_directory() upfront helps git://
proxy specification picked up from the correct place.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

One caller of deref_tag() was not careful enough to make sure
what deref_tag() returned was not NULL (i.e. we found a tag
object that points at an object we do not have).  Fix it, and
warn about refs that point at such an incomplete tag where
needed.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This allows the remote side (most notably, upload-pack) to show
additional information without affecting the downloader.  Peek-remote
does not ignore them -- this is to make it useful for Pasky's
automatic tag following.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

When more than two references need to be checked with
ref_newer() function, the second and later calls did not work
correctly.  This was because the later calls found commits
retained by the "struct object" layer that still had smudges
made by earlier calls.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Again I left the v2.6.11-tree tag behind.  My bad.

This commit makes sure that we do not barf when pushing a ref
that is a non-commitish tag.  You can update a remote ref under
the following conditions:

 * You can always use --force.
 * Creating a brand new ref is OK.
 * If the remote ref is exactly the same as what you are
   pushing, it is OK (nothing is pushed).
 * You can replace a commitish with another commitish which is a
   descendant of it, if you can verify the ancestry between them;
   this and the above means you have to have what you are replacing.
 * Otherwise you cannot update; you need to use --force.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This allows git-send-pack to push local refs to a destination
repository under different names.

Here is the name mapping rules for refs.

* If there is no ref mapping on the command line:

 - if '--all' is specified, it is equivalent to specifying
   <local> ":" <local> for all the existing local refs on the
   command line
 - otherwise, it is equivalent to specifying <ref> ":" <ref> for
   all the refs that exist on both sides.

* <name> is just a shorthand for <name> ":" <name>

* <src> ":" <dst>

  push ref that matches <src> to ref that matches <dst>.

  - It is an error if <src> does not match exactly one of local
    refs.

  - It is an error if <dst> matches more than one remote refs.

  - If <dst> does not match any remote refs, either

    - it has to start with "refs/"; <dst> is used as the
      destination literally in this case.

    - <src> == <dst> and the ref that matched the <src> must not
      exist in the set of remote refs; the ref matched <src>
      locally is used as the name of the destination.

For example,

  - "git-send-pack --all <remote>" works exactly as before;

  - "git-send-pack <remote> master:upstream" pushes local master
    to remote ref that matches "upstream".  If there is no such
    ref, it is an error.

  - "git-send-pack <remote> master:refs/heads/upstream" pushes
    local master to remote refs/heads/upstream, even when
    refs/heads/upstream does not exist.

  - "git-send-pack <remote> master" into an empty remote
    repository pushes the local ref/heads/master to the remote
    ref/heads/master.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When pushing into multi-user repository, or when pushing to a
repository from a local repository that has rebased branches
that has been pruned, the destination repository can have head
commits that are missing from the local repository.

This should not matter as long as the local head of the branch
being pushed is a proper superset of the destination branch, but
we ended up trying to run rev-list telling it to exclude objects
reachable from those heads missing from the local repository,
causing it to barf.  Prune those heads from the rev-list
parameter list, and make sure we do not try to push a branch
whose remote head is something we lack.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

send-pack had a confusing misfeature that "send-pack --all
master" updated all refs, while "send-pack --all" did not do
anything.  Make --all and explicit refs mutually exclusive, and
make sure "send-pack --all" updates all refs.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The check that the source is ahead of the destination incorrectly expects 
pop_most_recent_commit() to gracefully handle an empty list. 

Fix by just checking the list itself, rather than the return value of the 
pop function.

[jc: I did the test script that demonstrated the problem]
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This should make sure that if you have multiple people pushing to the
same tree, they cannot overwrite each others work, but have to merge
before being able to update the common reference tree.

It really just boils down to one "get_remote_heads()" function, and a
common "struct ref" structure definition.

This affects only refs that the other side doesn't already have. The
ones it has are still filtered by the ref selection.

This adds documentation for 'smarter push' family of commands.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Cut-and-paste dup noticed by Junio.  It's not even harmless, since a
match also causes that match to be invalidated, so this made it
impossible to update an existing branch by name.

I'd only tested the case of "ref doesn't exist at all on the other end",
which worked fine.

The protocol always supported it, but send-pack didn't actually know how
to tell the other side about a new branch/tag.

NOTE! You'll have to name it explicitly on the command line: if you
don't name any branches, git-send-pack will default to the branches that
already exist.

"git_path()" returns a static pathname pointer into the git directory
using a printf-like format specifier.

"head_ref()" works like "for_each_ref()", except for just the HEAD.

It's a generic thing for matching refs from the other side.

I want to use it for git-fetch-pack too.

send_pack() was declared to return "int" (although nobody cared), but
didn't actually return anything.

This makes the receiver always send a full list of valid refs, which
will allow us to do better packs, as well as handle creation of new
refs.  Eventually.  Right now we just moved the matching and enabled it.

So now you can do

	git-send-pack host:path branch1 branch2

to only send branches "branch1" and "branch2".

This concludes this lesson.  I've actually successfully sent an update
using the git-send-pack command.

Probably tons of work still to do, and nasty debugging, but it's now
actually potentially useful.

Me tired.

Right now it just shows which refs it picks up, and whether they are
the same or changed on the remote end. Getting there..

Like git-receive-pack, this is only partway done.