Merge branch 'jc/codingstyle-compare-with-null'

[thirdparty/git.git] / Documentation / git-pull.txt

git-pull(1)
===========

NAME
----
git-pull - Fetch from and integrate with another repository or a local branch


SYNOPSIS
--------
[verse]
'git pull' [<options>] [<repository> [<refspec>...]]


DESCRIPTION
-----------

Incorporates changes from a remote repository into the current
branch.  In its default mode, `git pull` is shorthand for
`git fetch` followed by `git merge FETCH_HEAD`.

More precisely, 'git pull' runs 'git fetch' with the given
parameters and calls 'git merge' to merge the retrieved branch
heads into the current branch.
With `--rebase`, it runs 'git rebase' instead of 'git merge'.

<repository> should be the name of a remote repository as
passed to linkgit:git-fetch[1].  <refspec> can name an
arbitrary remote ref (for example, the name of a tag) or even
a collection of refs with corresponding remote-tracking branches
(e.g., refs/heads/{asterisk}:refs/remotes/origin/{asterisk}),
but usually it is the name of a branch in the remote repository.

Default values for <repository> and <branch> are read from the
"remote" and "merge" configuration for the current branch
as set by linkgit:git-branch[1] `--track`.

Assume the following history exists and the current branch is
"`master`":

------------
	  A---B---C master on origin
	 /
    D---E---F---G master
	^
	origin/master in your repository
------------

Then "`git pull`" will fetch and replay the changes from the remote
`master` branch since it diverged from the local `master` (i.e., `E`)
until its current commit (`C`) on top of `master` and record the
result in a new commit along with the names of the two parent commits
and a log message from the user describing the changes.

------------
	  A---B---C origin/master
	 /         \
    D---E---F---G---H master
------------

See linkgit:git-merge[1] for details, including how conflicts
are presented and handled.

In Git 1.7.0 or later, to cancel a conflicting merge, use
`git reset --merge`.  *Warning*: In older versions of Git, running 'git pull'
with uncommitted changes is discouraged: while possible, it leaves you
in a state that may be hard to back out of in the case of a conflict.

If any of the remote changes overlap with local uncommitted changes,
the merge will be automatically canceled and the work tree untouched.
It is generally best to get any local changes in working order before
pulling or stash them away with linkgit:git-stash[1].

OPTIONS
-------

-q::
--quiet::
	This is passed to both underlying git-fetch to squelch reporting of
	during transfer, and underlying git-merge to squelch output during
	merging.

-v::
--verbose::
	Pass --verbose to git-fetch and git-merge.

--[no-]recurse-submodules[=yes|on-demand|no]::
	This option controls if new commits of populated submodules should
	be fetched, and if the working trees of active submodules should be
	updated, too (see linkgit:git-fetch[1], linkgit:git-config[1] and
	linkgit:gitmodules[5]).
+
If the checkout is done via rebase, local submodule commits are rebased as well.
+
If the update is done via merge, the submodule conflicts are resolved and checked out.

Options related to merging
~~~~~~~~~~~~~~~~~~~~~~~~~~

:git-pull: 1

include::merge-options.txt[]

-r::
--rebase[=false|true|merges|preserve|interactive]::
	When true, rebase the current branch on top of the upstream
	branch after fetching. If there is a remote-tracking branch
	corresponding to the upstream branch and the upstream branch
	was rebased since last fetched, the rebase uses that information
	to avoid rebasing non-local changes.
+
When set to `merges`, rebase using `git rebase --rebase-merges` so that
the local merge commits are included in the rebase (see
linkgit:git-rebase[1] for details).
+
When set to `preserve` (deprecated in favor of `merges`), rebase with the
`--preserve-merges` option passed to `git rebase` so that locally created
merge commits will not be flattened.
+
When false, merge the current branch into the upstream branch.
+
When `interactive`, enable the interactive mode of rebase.
+
See `pull.rebase`, `branch.<name>.rebase` and `branch.autoSetupRebase` in
linkgit:git-config[1] if you want to make `git pull` always use
`--rebase` instead of merging.
+
[NOTE]
This is a potentially _dangerous_ mode of operation.
It rewrites history, which does not bode well when you
published that history already.  Do *not* use this option
unless you have read linkgit:git-rebase[1] carefully.

--no-rebase::
	Override earlier --rebase.

Options related to fetching
~~~~~~~~~~~~~~~~~~~~~~~~~~~

include::fetch-options.txt[]

include::pull-fetch-param.txt[]

include::urls-remotes.txt[]

include::merge-strategies.txt[]

DEFAULT BEHAVIOUR
-----------------

Often people use `git pull` without giving any parameter.
Traditionally, this has been equivalent to saying `git pull
origin`.  However, when configuration `branch.<name>.remote` is
present while on branch `<name>`, that value is used instead of
`origin`.

In order to determine what URL to use to fetch from, the value
of the configuration `remote.<origin>.url` is consulted
and if there is not any such variable, the value on the `URL:` line
in `$GIT_DIR/remotes/<origin>` is used.

In order to determine what remote branches to fetch (and
optionally store in the remote-tracking branches) when the command is
run without any refspec parameters on the command line, values
of the configuration variable `remote.<origin>.fetch` are
consulted, and if there aren't any, `$GIT_DIR/remotes/<origin>`
is consulted and its `Pull:` lines are used.
In addition to the refspec formats described in the OPTIONS
section, you can have a globbing refspec that looks like this:

------------
refs/heads/*:refs/remotes/origin/*
------------

A globbing refspec must have a non-empty RHS (i.e. must store
what were fetched in remote-tracking branches), and its LHS and RHS
must end with `/*`.  The above specifies that all remote
branches are tracked using remote-tracking branches in
`refs/remotes/origin/` hierarchy under the same name.

The rule to determine which remote branch to merge after
fetching is a bit involved, in order not to break backward
compatibility.

If explicit refspecs were given on the command
line of `git pull`, they are all merged.

When no refspec was given on the command line, then `git pull`
uses the refspec from the configuration or
`$GIT_DIR/remotes/<origin>`.  In such cases, the following
rules apply:

. If `branch.<name>.merge` configuration for the current
  branch `<name>` exists, that is the name of the branch at the
  remote site that is merged.

. If the refspec is a globbing one, nothing is merged.

. Otherwise the remote branch of the first refspec is merged.


EXAMPLES
--------

* Update the remote-tracking branches for the repository
  you cloned from, then merge one of them into your
  current branch:
+
------------------------------------------------
$ git pull
$ git pull origin
------------------------------------------------
+
Normally the branch merged in is the HEAD of the remote repository,
but the choice is determined by the branch.<name>.remote and
branch.<name>.merge options; see linkgit:git-config[1] for details.

* Merge into the current branch the remote branch `next`:
+
------------------------------------------------
$ git pull origin next
------------------------------------------------
+
This leaves a copy of `next` temporarily in FETCH_HEAD, and
updates the remote-tracking branch `origin/next`.
The same can be done by invoking fetch and merge:
+
------------------------------------------------
$ git fetch origin
$ git merge origin/next
------------------------------------------------


If you tried a pull which resulted in complex conflicts and
would want to start over, you can recover with 'git reset'.


include::transfer-data-leaks.txt[]

BUGS
----
Using --recurse-submodules can only fetch new commits in already checked
out submodules right now. When e.g. upstream added a new submodule in the
just fetched commits of the superproject the submodule itself cannot be
fetched, making it impossible to check out that submodule later without
having to do a fetch again. This is expected to be fixed in a future Git
version.

SEE ALSO
--------
linkgit:git-fetch[1], linkgit:git-merge[1], linkgit:git-config[1]

GIT
---
Part of the linkgit:git[1] suite