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git/Documentation/git-bundle.txt
Jeff King 0d0bac67ce transport: drop support for git-over-rsync
The git-over-rsync protocol is inefficient and broken, and
has been for a long time. It transfers way more objects than
it needs (grabbing all of the remote's "objects/",
regardless of which objects we need). It does its own ad-hoc
parsing of loose and packed refs from the remote, but
doesn't properly override packed refs with loose ones,
leading to garbage results (e.g., expecting the other side
to have an object pointed to by a stale packed-refs entry,
or complaining that the other side has two copies of the
refs[1]).

This latter breakage means that nobody could have
successfully pulled from a moderately active repository
since cd547b4 (fetch/push: readd rsync support, 2007-10-01).

We never made an official deprecation notice in the release
notes for git's rsync protocol, but the tutorial has marked
it as such since 914328a (Update tutorial., 2005-08-30).
And on the mailing list as far back as Oct 2005, we can find
Junio mentioning it as having "been deprecated for quite
some time."[2,3,4]. So it was old news then; cogito had
deprecated the transport in July of 2005[5] (though it did
come back briefly when Linus broke git-http-pull!).

Of course some people professed their love of rsync through
2006, but Linus clarified in his usual gentle manner[6]:

  > Thanks!  This is why I still use rsync, even though
  > everybody and their mother tells me "Linus says rsync is
  > deprecated."

  No. You're using rsync because you're actively doing
  something _wrong_.

The deprecation sentiment was reinforced in 2008, with a
mention that cloning via rsync is broken (with no fix)[7].

Even the commit porting rsync over to C from shell (cd547b4)
lists it as deprecated! So between the 10 years of informal
warnings, and the fact that it has been severely broken
since 2007, it's probably safe to simply remove it without
further deprecation warnings.

[1] http://article.gmane.org/gmane.comp.version-control.git/285101
[2] http://article.gmane.org/gmane.comp.version-control.git/10093
[3] http://article.gmane.org/gmane.comp.version-control.git/17734
[4] http://article.gmane.org/gmane.comp.version-control.git/18911
[5] http://article.gmane.org/gmane.comp.version-control.git/5617
[6] http://article.gmane.org/gmane.comp.version-control.git/19354
[7] http://article.gmane.org/gmane.comp.version-control.git/103635

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-01 13:07:41 -08:00

205 lines
6.9 KiB
Text

git-bundle(1)
=============
NAME
----
git-bundle - Move objects and refs by archive
SYNOPSIS
--------
[verse]
'git bundle' create <file> <git-rev-list-args>
'git bundle' verify <file>
'git bundle' list-heads <file> [<refname>...]
'git bundle' unbundle <file> [<refname>...]
DESCRIPTION
-----------
Some workflows require that one or more branches of development on one
machine be replicated on another machine, but the two machines cannot
be directly connected, and therefore the interactive Git protocols (git,
ssh, http) cannot be used. This command provides support for
'git fetch' and 'git pull' to operate by packaging objects and references
in an archive at the originating machine, then importing those into
another repository using 'git fetch' and 'git pull'
after moving the archive by some means (e.g., by sneakernet). As no
direct connection between the repositories exists, the user must specify a
basis for the bundle that is held by the destination repository: the
bundle assumes that all objects in the basis are already in the
destination repository.
OPTIONS
-------
create <file>::
Used to create a bundle named 'file'. This requires the
'git-rev-list-args' arguments to define the bundle contents.
verify <file>::
Used to check that a bundle file is valid and will apply
cleanly to the current repository. This includes checks on the
bundle format itself as well as checking that the prerequisite
commits exist and are fully linked in the current repository.
'git bundle' prints a list of missing commits, if any, and exits
with a non-zero status.
list-heads <file>::
Lists the references defined in the bundle. If followed by a
list of references, only references matching those given are
printed out.
unbundle <file>::
Passes the objects in the bundle to 'git index-pack'
for storage in the repository, then prints the names of all
defined references. If a list of references is given, only
references matching those in the list are printed. This command is
really plumbing, intended to be called only by 'git fetch'.
<git-rev-list-args>::
A list of arguments, acceptable to 'git rev-parse' and
'git rev-list' (and containing a named ref, see SPECIFYING REFERENCES
below), that specifies the specific objects and references
to transport. For example, `master~10..master` causes the
current master reference to be packaged along with all objects
added since its 10th ancestor commit. There is no explicit
limit to the number of references and objects that may be
packaged.
[<refname>...]::
A list of references used to limit the references reported as
available. This is principally of use to 'git fetch', which
expects to receive only those references asked for and not
necessarily everything in the pack (in this case, 'git bundle' acts
like 'git fetch-pack').
SPECIFYING REFERENCES
---------------------
'git bundle' will only package references that are shown by
'git show-ref': this includes heads, tags, and remote heads. References
such as `master~1` cannot be packaged, but are perfectly suitable for
defining the basis. More than one reference may be packaged, and more
than one basis can be specified. The objects packaged are those not
contained in the union of the given bases. Each basis can be
specified explicitly (e.g. `^master~10`), or implicitly (e.g.
`master~10..master`, `--since=10.days.ago master`).
It is very important that the basis used be held by the destination.
It is okay to err on the side of caution, causing the bundle file
to contain objects already in the destination, as these are ignored
when unpacking at the destination.
EXAMPLE
-------
Assume you want to transfer the history from a repository R1 on machine A
to another repository R2 on machine B.
For whatever reason, direct connection between A and B is not allowed,
but we can move data from A to B via some mechanism (CD, email, etc.).
We want to update R2 with development made on the branch master in R1.
To bootstrap the process, you can first create a bundle that does not have
any basis. You can use a tag to remember up to what commit you last
processed, in order to make it easy to later update the other repository
with an incremental bundle:
----------------
machineA$ cd R1
machineA$ git bundle create file.bundle master
machineA$ git tag -f lastR2bundle master
----------------
Then you transfer file.bundle to the target machine B. Because this
bundle does not require any existing object to be extracted, you can
create a new repository on machine B by cloning from it:
----------------
machineB$ git clone -b master /home/me/tmp/file.bundle R2
----------------
This will define a remote called "origin" in the resulting repository that
lets you fetch and pull from the bundle. The $GIT_DIR/config file in R2 will
have an entry like this:
------------------------
[remote "origin"]
url = /home/me/tmp/file.bundle
fetch = refs/heads/*:refs/remotes/origin/*
------------------------
To update the resulting mine.git repository, you can fetch or pull after
replacing the bundle stored at /home/me/tmp/file.bundle with incremental
updates.
After working some more in the original repository, you can create an
incremental bundle to update the other repository:
----------------
machineA$ cd R1
machineA$ git bundle create file.bundle lastR2bundle..master
machineA$ git tag -f lastR2bundle master
----------------
You then transfer the bundle to the other machine to replace
/home/me/tmp/file.bundle, and pull from it.
----------------
machineB$ cd R2
machineB$ git pull
----------------
If you know up to what commit the intended recipient repository should
have the necessary objects, you can use that knowledge to specify the
basis, giving a cut-off point to limit the revisions and objects that go
in the resulting bundle. The previous example used the lastR2bundle tag
for this purpose, but you can use any other options that you would give to
the linkgit:git-log[1] command. Here are more examples:
You can use a tag that is present in both:
----------------
$ git bundle create mybundle v1.0.0..master
----------------
You can use a basis based on time:
----------------
$ git bundle create mybundle --since=10.days master
----------------
You can use the number of commits:
----------------
$ git bundle create mybundle -10 master
----------------
You can run `git-bundle verify` to see if you can extract from a bundle
that was created with a basis:
----------------
$ git bundle verify mybundle
----------------
This will list what commits you must have in order to extract from the
bundle and will error out if you do not have them.
A bundle from a recipient repository's point of view is just like a
regular repository which it fetches or pulls from. You can, for example, map
references when fetching:
----------------
$ git fetch mybundle master:localRef
----------------
You can also see what references it offers:
----------------
$ git ls-remote mybundle
----------------
GIT
---
Part of the linkgit:git[1] suite