git-fetch(1) Git Manual git-fetch(1)
NAME
git-fetch - Download objects and refs from another repository
SYNOPSIS
git fetch [<options>] [<repository> [<refspec>...]]
git fetch [<options>] <group>
git fetch --multiple [<options>] [(<repository> | <group>)...]
git fetch --all [<options>]
DESCRIPTION
Fetch branches and/or tags (collectively, "refs") from one or more other
repositories, along with the objects necessary to complete their
histories. Remote-tracking branches are updated (see the description of
<refspec> below for ways to control this behavior).
By default, any tag that points into the histories being fetched is also
fetched; the effect is to fetch tags that point at branches that you are
interested in. This default behavior can be changed by using the --tags
or --no-tags options or by configuring remote.<name>.tagOpt. By using a
refspec that fetches tags explicitly, you can fetch tags that do not
point into branches you are interested in as well.
git fetch can fetch from either a single named repository or URL, or from
several repositories at once if <group> is given and there is a
remotes.<group> entry in the configuration file. (See git-config(1)).
When no remote is specified, by default the origin remote will be used,
unless there's an upstream branch configured for the current branch.
The names of refs that are fetched, together with the object names they
point at, are written to .git/FETCH_HEAD. This information may be used by
scripts or other git commands, such as git-pull(1).
OPTIONS
--all
Fetch all remotes.
-a, --append
Append ref names and object names of fetched refs to the existing
contents of .git/FETCH_HEAD. Without this option old data in
.git/FETCH_HEAD will be overwritten.
--atomic
Use an atomic transaction to update local refs. Either all refs are
updated, or on error, no refs are updated.
--depth=<depth>
Limit fetching to the specified number of commits from the tip of
each remote branch history. If fetching to a shallow repository
created by git clone with --depth=<depth> option (see git-clone(1)),
deepen or shorten the history to the specified number of commits.
Tags for the deepened commits are not fetched.
--deepen=<depth>
Similar to --depth, except it specifies the number of commits from
the current shallow boundary instead of from the tip of each remote
branch history.
--shallow-since=<date>
Deepen or shorten the history of a shallow repository to include all
reachable commits after <date>.
--shallow-exclude=<revision>
Deepen or shorten the history of a shallow repository to exclude
commits reachable from a specified remote branch or tag. This option
can be specified multiple times.
--unshallow
If the source repository is complete, convert a shallow repository to
a complete one, removing all the limitations imposed by shallow
repositories.
If the source repository is shallow, fetch as much as possible so
that the current repository has the same history as the source
repository.
--update-shallow
By default when fetching from a shallow repository, git fetch refuses
refs that require updating .git/shallow. This option updates
.git/shallow and accept such refs.
--negotiation-tip=<commit|glob>
By default, Git will report, to the server, commits reachable from
all local refs to find common commits in an attempt to reduce the
size of the to-be-received packfile. If specified, Git will only
report commits reachable from the given tips. This is useful to speed
up fetches when the user knows which local ref is likely to have
commits in common with the upstream ref being fetched.
This option may be specified more than once; if so, Git will report
commits reachable from any of the given commits.
The argument to this option may be a glob on ref names, a ref, or the
(possibly abbreviated) SHA-1 of a commit. Specifying a glob is
equivalent to specifying this option multiple times, one for each
matching ref name.
See also the fetch.negotiationAlgorithm and push.negotiate
configuration variables documented in git-config(1), and the
--negotiate-only option below.
--negotiate-only
Do not fetch anything from the server, and instead print the
ancestors of the provided --negotiation-tip=* arguments, which we
have in common with the server.
This is incompatible with --recurse-submodules=[yes|on-demand].
Internally this is used to implement the push.negotiate option, see
git-config(1).
--dry-run
Show what would be done, without making any changes.
--[no-]write-fetch-head
Write the list of remote refs fetched in the FETCH_HEAD file directly
under $GIT_DIR. This is the default. Passing --no-write-fetch-head
from the command line tells Git not to write the file. Under
--dry-run option, the file is never written.
-f, --force
When git fetch is used with <src>:<dst> refspec it may refuse to
update the local branch as discussed in the <refspec> part below.
This option overrides that check.
-k, --keep
Keep downloaded pack.
--multiple
Allow several <repository> and <group> arguments to be specified. No
<refspec>s may be specified.
--[no-]auto-maintenance, --[no-]auto-gc
Run git maintenance run --auto at the end to perform automatic
repository maintenance if needed. (--[no-]auto-gc is a synonym.) This
is enabled by default.
--[no-]write-commit-graph
Write a commit-graph after fetching. This overrides the config
setting fetch.writeCommitGraph.
--prefetch
Modify the configured refspec to place all refs into the
refs/prefetch/ namespace. See the prefetch task in git-
maintenance(1).
-p, --prune
Before fetching, remove any remote-tracking references that no longer
exist on the remote. Tags are not subject to pruning if they are
fetched only because of the default tag auto-following or due to a
--tags option. However, if tags are fetched due to an explicit
refspec (either on the command line or in the remote configuration,
for example if the remote was cloned with the --mirror option), then
they are also subject to pruning. Supplying --prune-tags is a
shorthand for providing the tag refspec.
See the PRUNING section below for more details.
-P, --prune-tags
Before fetching, remove any local tags that no longer exist on the
remote if --prune is enabled. This option should be used more
carefully, unlike --prune it will remove any local references (local
tags) that have been created. This option is a shorthand for
providing the explicit tag refspec along with --prune, see the
discussion about that in its documentation.
See the PRUNING section below for more details.
-n, --no-tags
By default, tags that point at objects that are downloaded from the
remote repository are fetched and stored locally. This option
disables this automatic tag following. The default behavior for a
remote may be specified with the remote.<name>.tagOpt setting. See
git-config(1).
--refetch
Instead of negotiating with the server to avoid transferring commits
and associated objects that are already present locally, this option
fetches all objects as a fresh clone would. Use this to reapply a
partial clone filter from configuration or using --filter= when the
filter definition has changed. Automatic post-fetch maintenance will
perform object database pack consolidation to remove any duplicate
objects.
--refmap=<refspec>
When fetching refs listed on the command line, use the specified
refspec (can be given more than once) to map the refs to
remote-tracking branches, instead of the values of remote.*.fetch
configuration variables for the remote repository. Providing an empty
<refspec> to the --refmap option causes Git to ignore the configured
refspecs and rely entirely on the refspecs supplied as command-line
arguments. See section on "Configured Remote-tracking Branches" for
details.
-t, --tags
Fetch all tags from the remote (i.e., fetch remote tags refs/tags/*
into local tags with the same name), in addition to whatever else
would otherwise be fetched. Using this option alone does not subject
tags to pruning, even if --prune is used (though tags may be pruned
anyway if they are also the destination of an explicit refspec; see
--prune).
--recurse-submodules[=yes|on-demand|no]
This option controls if and under what conditions new commits of
submodules should be fetched too. When recursing through submodules,
git fetch always attempts to fetch "changed" submodules, that is, a
submodule that has commits that are referenced by a newly fetched
superproject commit but are missing in the local submodule clone. A
changed submodule can be fetched as long as it is present locally
e.g. in $GIT_DIR/modules/ (see gitsubmodules(7)); if the upstream
adds a new submodule, that submodule cannot be fetched until it is
cloned e.g. by git submodule update.
When set to on-demand, only changed submodules are fetched. When set
to yes, all populated submodules are fetched and submodules that are
both unpopulated and changed are fetched. When set to no, submodules
are never fetched.
When unspecified, this uses the value of fetch.recurseSubmodules if
it is set (see git-config(1)), defaulting to on-demand if unset. When
this option is used without any value, it defaults to yes.
-j, --jobs=<n>
Number of parallel children to be used for all forms of fetching.
If the --multiple option was specified, the different remotes will be
fetched in parallel. If multiple submodules are fetched, they will be
fetched in parallel. To control them independently, use the config
settings fetch.parallel and submodule.fetchJobs (see git-config(1)).
Typically, parallel recursive and multi-remote fetches will be
faster. By default fetches are performed sequentially, not in
parallel.
--no-recurse-submodules
Disable recursive fetching of submodules (this has the same effect as
using the --recurse-submodules=no option).
--set-upstream
If the remote is fetched successfully, add upstream (tracking)
reference, used by argument-less git-pull(1) and other commands. For
more information, see branch.<name>.merge and branch.<name>.remote in
git-config(1).
--submodule-prefix=<path>
Prepend <path> to paths printed in informative messages such as
"Fetching submodule foo". This option is used internally when
recursing over submodules.
--recurse-submodules-default=[yes|on-demand]
This option is used internally to temporarily provide a non-negative
default value for the --recurse-submodules option. All other methods
of configuring fetch's submodule recursion (such as settings in
gitmodules(5) and git-config(1)) override this option, as does
specifying --[no-]recurse-submodules directly.
-u, --update-head-ok
By default git fetch refuses to update the head which corresponds to
the current branch. This flag disables the check. This is purely for
the internal use for git pull to communicate with git fetch, and
unless you are implementing your own Porcelain you are not supposed
to use it.
--upload-pack <upload-pack>
When given, and the repository to fetch from is handled by git
fetch-pack, --exec=<upload-pack> is passed to the command to specify
non-default path for the command run on the other end.
-q, --quiet
Pass --quiet to git-fetch-pack and silence any other internally used
git commands. Progress is not reported to the standard error stream.
-v, --verbose
Be verbose.
--progress
Progress status is reported on the standard error stream by default
when it is attached to a terminal, unless -q is specified. This flag
forces progress status even if the standard error stream is not
directed to a terminal.
-o <option>, --server-option=<option>
Transmit the given string to the server when communicating using
protocol version 2. The given string must not contain a NUL or LF
character. The server's handling of server options, including unknown
ones, is server-specific. When multiple --server-option=<option> are
given, they are all sent to the other side in the order listed on the
command line.
--show-forced-updates
By default, git checks if a branch is force-updated during fetch.
This can be disabled through fetch.showForcedUpdates, but the
--show-forced-updates option guarantees this check occurs. See git-
config(1).
--no-show-forced-updates
By default, git checks if a branch is force-updated during fetch.
Pass --no-show-forced-updates or set fetch.showForcedUpdates to false
to skip this check for performance reasons. If used during git-pull
the --ff-only option will still check for forced updates before
attempting a fast-forward update. See git-config(1).
-4, --ipv4
Use IPv4 addresses only, ignoring IPv6 addresses.
-6, --ipv6
Use IPv6 addresses only, ignoring IPv4 addresses.
<repository>
The "remote" repository that is the source of a fetch or pull
operation. This parameter can be either a URL (see the section GIT
URLS below) or the name of a remote (see the section REMOTES below).
<group>
A name referring to a list of repositories as the value of
remotes.<group> in the configuration file. (See git-config(1)).
<refspec>
Specifies which refs to fetch and which local refs to update. When no
<refspec>s appear on the command line, the refs to fetch are read
from remote.<repository>.fetch variables instead (see CONFIGURED
REMOTE-TRACKING BRANCHES below).
The format of a <refspec> parameter is an optional plus +, followed
by the source <src>, followed by a colon :, followed by the
destination ref <dst>. The colon can be omitted when <dst> is empty.
<src> is typically a ref, but it can also be a fully spelled hex
object name.
A <refspec> may contain a * in its <src> to indicate a simple pattern
match. Such a refspec functions like a glob that matches any ref with
the same prefix. A pattern <refspec> must have a * in both the <src>
and <dst>. It will map refs to the destination by replacing the *
with the contents matched from the source.
If a refspec is prefixed by ^, it will be interpreted as a negative
refspec. Rather than specifying which refs to fetch or which local
refs to update, such a refspec will instead specify refs to exclude.
A ref will be considered to match if it matches at least one positive
refspec, and does not match any negative refspec. Negative refspecs
can be useful to restrict the scope of a pattern refspec so that it
will not include specific refs. Negative refspecs can themselves be
pattern refspecs. However, they may only contain a <src> and do not
specify a <dst>. Fully spelled out hex object names are also not
supported.
tag <tag> means the same as refs/tags/<tag>:refs/tags/<tag>; it
requests fetching everything up to the given tag.
The remote ref that matches <src> is fetched, and if <dst> is not an
empty string, an attempt is made to update the local ref that matches
it.
Whether that update is allowed without --force depends on the ref
namespace it's being fetched to, the type of object being fetched,
and whether the update is considered to be a fast-forward. Generally,
the same rules apply for fetching as when pushing, see the
<refspec>... section of git-push(1) for what those are. Exceptions to
those rules particular to git fetch are noted below.
Until Git version 2.20, and unlike when pushing with git-push(1), any
updates to refs/tags/* would be accepted without + in the refspec (or
--force). When fetching, we promiscuously considered all tag updates
from a remote to be forced fetches. Since Git version 2.20, fetching
to update refs/tags/* works the same way as when pushing. I.e. any
updates will be rejected without + in the refspec (or --force).
Unlike when pushing with git-push(1), any updates outside of
refs/{tags,heads}/* will be accepted without + in the refspec (or
--force), whether that's swapping e.g. a tree object for a blob, or a
commit for another commit that's doesn't have the previous commit as
an ancestor etc.
Unlike when pushing with git-push(1), there is no configuration
which'll amend these rules, and nothing like a pre-fetch hook
analogous to the pre-receive hook.
As with pushing with git-push(1), all of the rules described above
about what's not allowed as an update can be overridden by adding an
the optional leading + to a refspec (or using --force command line
option). The only exception to this is that no amount of forcing will
make the refs/heads/* namespace accept a non-commit object.
Note
When the remote branch you want to fetch is known to be rewound
and rebased regularly, it is expected that its new tip will not
be descendant of its previous tip (as stored in your
remote-tracking branch the last time you fetched). You would want
to use the + sign to indicate non-fast-forward updates will be
needed for such branches. There is no way to determine or declare
that a branch will be made available in a repository with this
behavior; the pulling user simply must know this is the expected
usage pattern for a branch.
--stdin
Read refspecs, one per line, from stdin in addition to those provided
as arguments. The "tag <name>" format is not supported.
GIT URLS
In general, URLs contain information about the transport protocol, the
address of the remote server, and the path to the repository. Depending
on the transport protocol, some of this information may be absent.
Git supports ssh, git, http, and https protocols (in addition, ftp, and
ftps can be used for fetching, but this is inefficient and deprecated; do
not use it).
The native transport (i.e. git:// URL) does no authentication and should
be used with caution on unsecured networks.
The following syntaxes may be used with them:
o ssh://[user@]host.xz[:port]/path/to/repo.git/
o git://host.xz[:port]/path/to/repo.git/
o http[s]://host.xz[:port]/path/to/repo.git/
o ftp[s]://host.xz[:port]/path/to/repo.git/
An alternative scp-like syntax may also be used with the ssh protocol:
o [user@]host.xz:path/to/repo.git/
This syntax is only recognized if there are no slashes before the first
colon. This helps differentiate a local path that contains a colon. For
example the local path foo:bar could be specified as an absolute path or
./foo:bar to avoid being misinterpreted as an ssh url.
The ssh and git protocols additionally support ~username expansion:
o ssh://[user@]host.xz[:port]/~[user]/path/to/repo.git/
o git://host.xz[:port]/~[user]/path/to/repo.git/
o [user@]host.xz:/~[user]/path/to/repo.git/
For local repositories, also supported by Git natively, the following
syntaxes may be used:
o /path/to/repo.git/
o file:///path/to/repo.git/
These two syntaxes are mostly equivalent, except when cloning, when the
former implies --local option. See git-clone(1) for details.
git clone, git fetch and git pull, but not git push, will also accept a
suitable bundle file. See git-bundle(1).
When Git doesn't know how to handle a certain transport protocol, it
attempts to use the remote-<transport> remote helper, if one exists. To
explicitly request a remote helper, the following syntax may be used:
o <transport>::<address>
where <address> may be a path, a server and path, or an arbitrary
URL-like string recognized by the specific remote helper being invoked.
See gitremote-helpers(7) for details.
If there are a large number of similarly-named remote repositories and
you want to use a different format for them (such that the URLs you use
will be rewritten into URLs that work), you can create a configuration
section of the form:
[url "<actual url base>"]
insteadOf = <other url base>
For example, with this:
[url "git://git.host.xz/"]
insteadOf = host.xz:/path/to/
insteadOf = work:
a URL like "work:repo.git" or like "host.xz:/path/to/repo.git" will be
rewritten in any context that takes a URL to be
"git://git.host.xz/repo.git".
If you want to rewrite URLs for push only, you can create a configuration
section of the form:
[url "<actual url base>"]
pushInsteadOf = <other url base>
For example, with this:
[url "ssh://example.org/"]
pushInsteadOf = git://example.org/
a URL like "git://example.org/path/to/repo.git" will be rewritten to
"ssh://example.org/path/to/repo.git" for pushes, but pulls will still use
the original URL.
REMOTES
The name of one of the following can be used instead of a URL as
<repository> argument:
o a remote in the Git configuration file: $GIT_DIR/config,
o a file in the $GIT_DIR/remotes directory, or
o a file in the $GIT_DIR/branches directory.
All of these also allow you to omit the refspec from the command line
because they each contain a refspec which git will use by default.
Named remote in configuration file
You can choose to provide the name of a remote which you had previously
configured using git-remote(1), git-config(1) or even by a manual edit to
the $GIT_DIR/config file. The URL of this remote will be used to access
the repository. The refspec of this remote will be used by default when
you do not provide a refspec on the command line. The entry in the config
file would appear like this:
[remote "<name>"]
url = <URL>
pushurl = <pushurl>
push = <refspec>
fetch = <refspec>
The <pushurl> is used for pushes only. It is optional and defaults to
<URL>. Pushing to a remote affects all defined pushurls or to all defined
urls if no pushurls are defined. Fetch, however, will only fetch from the
first defined url if muliple urls are defined.
Named file in $GIT_DIR/remotes
You can choose to provide the name of a file in $GIT_DIR/remotes. The URL
in this file will be used to access the repository. The refspec in this
file will be used as default when you do not provide a refspec on the
command line. This file should have the following format:
URL: one of the above URL format
Push: <refspec>
Pull: <refspec>
Push: lines are used by git push and Pull: lines are used by git pull and
git fetch. Multiple Push: and Pull: lines may be specified for additional
branch mappings.
Named file in $GIT_DIR/branches
You can choose to provide the name of a file in $GIT_DIR/branches. The
URL in this file will be used to access the repository. This file should
have the following format:
<URL>#<head>
<URL> is required; #<head> is optional.
Depending on the operation, git will use one of the following refspecs,
if you don't provide one on the command line. <branch> is the name of
this file in $GIT_DIR/branches and <head> defaults to master.
git fetch uses:
refs/heads/<head>:refs/heads/<branch>
git push uses:
HEAD:refs/heads/<head>
CONFIGURED REMOTE-TRACKING BRANCHES
You often interact with the same remote repository by regularly and
repeatedly fetching from it. In order to keep track of the progress of
such a remote repository, git fetch allows you to configure
remote.<repository>.fetch configuration variables.
Typically such a variable may look like this:
[remote "origin"]
fetch = +refs/heads/*:refs/remotes/origin/*
This configuration is used in two ways:
o When git fetch is run without specifying what branches and/or tags to
fetch on the command line, e.g. git fetch origin or git fetch,
remote.<repository>.fetch values are used as the refspecs--they
specify which refs to fetch and which local refs to update. The
example above will fetch all branches that exist in the origin (i.e.
any ref that matches the left-hand side of the value, refs/heads/*)
and update the corresponding remote-tracking branches in the
refs/remotes/origin/* hierarchy.
o When git fetch is run with explicit branches and/or tags to fetch on
the command line, e.g. git fetch origin master, the <refspec>s given
on the command line determine what are to be fetched (e.g. master in
the example, which is a short-hand for master:, which in turn means
"fetch the master branch but I do not explicitly say what
remote-tracking branch to update with it from the command line"), and
the example command will fetch only the master branch. The
remote.<repository>.fetch values determine which remote-tracking
branch, if any, is updated. When used in this way, the
remote.<repository>.fetch values do not have any effect in deciding
what gets fetched (i.e. the values are not used as refspecs when the
command-line lists refspecs); they are only used to decide where the
refs that are fetched are stored by acting as a mapping.
The latter use of the remote.<repository>.fetch values can be overridden
by giving the --refmap=<refspec> parameter(s) on the command line.
PRUNING
Git has a default disposition of keeping data unless it's explicitly
thrown away; this extends to holding onto local references to branches on
remotes that have themselves deleted those branches.
If left to accumulate, these stale references might make performance
worse on big and busy repos that have a lot of branch churn, and e.g.
make the output of commands like git branch -a --contains <commit>
needlessly verbose, as well as impacting anything else that'll work with
the complete set of known references.
These remote-tracking references can be deleted as a one-off with either
of:
# While fetching
$ git fetch --prune <name>
# Only prune, don't fetch
$ git remote prune <name>
To prune references as part of your normal workflow without needing to
remember to run that, set fetch.prune globally, or remote.<name>.prune
per-remote in the config. See git-config(1).
Here's where things get tricky and more specific. The pruning feature
doesn't actually care about branches, instead it'll prune local <-->
remote-references as a function of the refspec of the remote (see
<refspec> and CONFIGURED REMOTE-TRACKING BRANCHES above).
Therefore if the refspec for the remote includes e.g.
refs/tags/*:refs/tags/*, or you manually run e.g. git fetch --prune
<name> "refs/tags/*:refs/tags/*" it won't be stale remote tracking
branches that are deleted, but any local tag that doesn't exist on the
remote.
This might not be what you expect, i.e. you want to prune remote <name>,
but also explicitly fetch tags from it, so when you fetch from it you
delete all your local tags, most of which may not have come from the
<name> remote in the first place.
So be careful when using this with a refspec like
refs/tags/*:refs/tags/*, or any other refspec which might map references
from multiple remotes to the same local namespace.
Since keeping up-to-date with both branches and tags on the remote is a
common use-case the --prune-tags option can be supplied along with
--prune to prune local tags that don't exist on the remote, and
force-update those tags that differ. Tag pruning can also be enabled with
fetch.pruneTags or remote.<name>.pruneTags in the config. See git-
config(1).
The --prune-tags option is equivalent to having refs/tags/*:refs/tags/*
declared in the refspecs of the remote. This can lead to some seemingly
strange interactions:
# These both fetch tags
$ git fetch --no-tags origin 'refs/tags/*:refs/tags/*'
$ git fetch --no-tags --prune-tags origin
The reason it doesn't error out when provided without --prune or its
config versions is for flexibility of the configured versions, and to
maintain a 1=1 mapping between what the command line flags do, and what
the configuration versions do.
It's reasonable to e.g. configure fetch.pruneTags=true in ~/.gitconfig to
have tags pruned whenever git fetch --prune is run, without making every
invocation of git fetch without --prune an error.
Pruning tags with --prune-tags also works when fetching a URL instead of
a named remote. These will all prune tags not found on origin:
$ git fetch origin --prune --prune-tags
$ git fetch origin --prune 'refs/tags/*:refs/tags/*'
$ git fetch <url of origin> --prune --prune-tags
$ git fetch <url of origin> --prune 'refs/tags/*:refs/tags/*'
OUTPUT
The output of "git fetch" depends on the transport method used; this
section describes the output when fetching over the Git protocol (either
locally or via ssh) and Smart HTTP protocol.
The status of the fetch is output in tabular form, with each line
representing the status of a single ref. Each line is of the form:
<flag> <summary> <from> -> <to> [<reason>]
The status of up-to-date refs is shown only if the --verbose option is
used.
In compact output mode, specified with configuration variable
fetch.output, if either entire <from> or <to> is found in the other
string, it will be substituted with * in the other string. For example,
master -> origin/master becomes master -> origin/*.
flag
A single character indicating the status of the ref:
(space)
for a successfully fetched fast-forward;
+
for a successful forced update;
-
for a successfully pruned ref;
t
for a successful tag update;
*
for a successfully fetched new ref;
!
for a ref that was rejected or failed to update; and
=
for a ref that was up to date and did not need fetching.
summary
For a successfully fetched ref, the summary shows the old and new
values of the ref in a form suitable for using as an argument to git
log (this is <old>..<new> in most cases, and <old>...<new> for forced
non-fast-forward updates).
from
The name of the remote ref being fetched from, minus its refs/<type>/
prefix. In the case of deletion, the name of the remote ref is
"(none)".
to
The name of the local ref being updated, minus its refs/<type>/
prefix.
reason
A human-readable explanation. In the case of successfully fetched
refs, no explanation is needed. For a failed ref, the reason for
failure is described.
EXAMPLES
o Update the remote-tracking branches:
$ git fetch origin
The above command copies all branches from the remote refs/heads/
namespace and stores them to the local refs/remotes/origin/
namespace, unless the remote.<repository>.fetch option is used to
specify a non-default refspec.
o Using refspecs explicitly:
$ git fetch origin +seen:seen maint:tmp
This updates (or creates, as necessary) branches seen and tmp in the
local repository by fetching from the branches (respectively) seen
and maint from the remote repository.
The seen branch will be updated even if it does not fast-forward,
because it is prefixed with a plus sign; tmp will not be.
o Peek at a remote's branch, without configuring the remote in your
local repository:
$ git fetch git://git.kernel.org/pub/scm/git/git.git maint
$ git log FETCH_HEAD
The first command fetches the maint branch from the repository at
git://git.kernel.org/pub/scm/git/git.git and the second command uses
FETCH_HEAD to examine the branch with git-log(1). The fetched objects
will eventually be removed by git's built-in housekeeping (see git-
gc(1)).
SECURITY
The fetch and push protocols are not designed to prevent one side from
stealing data from the other repository that was not intended to be
shared. If you have private data that you need to protect from a
malicious peer, your best option is to store it in another repository.
This applies to both clients and servers. In particular, namespaces on a
server are not effective for read access control; you should only grant
read access to a namespace to clients that you would trust with read
access to the entire repository.
The known attack vectors are as follows:
1. The victim sends "have" lines advertising the IDs of objects it has
that are not explicitly intended to be shared but can be used to
optimize the transfer if the peer also has them. The attacker chooses
an object ID X to steal and sends a ref to X, but isn't required to
send the content of X because the victim already has it. Now the
victim believes that the attacker has X, and it sends the content of
X back to the attacker later. (This attack is most straightforward
for a client to perform on a server, by creating a ref to X in the
namespace the client has access to and then fetching it. The most
likely way for a server to perform it on a client is to "merge" X
into a public branch and hope that the user does additional work on
this branch and pushes it back to the server without noticing the
merge.)
2. As in #1, the attacker chooses an object ID X to steal. The victim
sends an object Y that the attacker already has, and the attacker
falsely claims to have X and not Y, so the victim sends Y as a delta
against X. The delta reveals regions of X that are similar to Y to
the attacker.
CONFIGURATION
Everything below this line in this section is selectively included from
the git-config(1) documentation. The content is the same as what's found
there:
fetch.recurseSubmodules
This option controls whether git fetch (and the underlying fetch in
git pull) will recursively fetch into populated submodules. This
option can be set either to a boolean value or to on-demand. Setting
it to a boolean changes the behavior of fetch and pull to recurse
unconditionally into submodules when set to true or to not recurse at
all when set to false. When set to on-demand, fetch and pull will
only recurse into a populated submodule when its superproject
retrieves a commit that updates the submodule's reference. Defaults
to on-demand, or to the value of submodule.recurse if set.
fetch.fsckObjects
If it is set to true, git-fetch-pack will check all fetched objects.
See transfer.fsckObjects for what's checked. Defaults to false. If
not set, the value of transfer.fsckObjects is used instead.
fetch.fsck.<msg-id>
Acts like fsck.<msg-id>, but is used by git-fetch-pack(1) instead of
git-fsck(1). See the fsck.<msg-id> documentation for details.
fetch.fsck.skipList
Acts like fsck.skipList, but is used by git-fetch-pack(1) instead of
git-fsck(1). See the fsck.skipList documentation for details.
fetch.unpackLimit
If the number of objects fetched over the Git native transfer is
below this limit, then the objects will be unpacked into loose object
files. However if the number of received objects equals or exceeds
this limit then the received pack will be stored as a pack, after
adding any missing delta bases. Storing the pack from a push can make
the push operation complete faster, especially on slow filesystems.
If not set, the value of transfer.unpackLimit is used instead.
fetch.prune
If true, fetch will automatically behave as if the --prune option was
given on the command line. See also remote.<name>.prune and the
PRUNING section of git-fetch(1).
fetch.pruneTags
If true, fetch will automatically behave as if the
refs/tags/*:refs/tags/* refspec was provided when pruning, if not set
already. This allows for setting both this option and fetch.prune to
maintain a 1=1 mapping to upstream refs. See also
git-fetch(1).
fetch.output
Control how ref update status is printed. Valid values are full and
git-fetch(1)
for detail.
fetch.negotiationAlgorithm
Control how information about the commits in the local repository is
sent when negotiating the contents of the packfile to be sent by the
server. Set to "consecutive" to use an algorithm that walks over
consecutive commits checking each one. Set to "skipping" to use an
algorithm that skips commits in an effort to converge faster, but may
result in a larger-than-necessary packfile; or set to "noop" to not
send any information at all, which will almost certainly result in a
larger-than-necessary packfile, but will skip the negotiation step.
Set to "default" to override settings made previously and use the
default behaviour. The default is normally "consecutive", but if
feature.experimental is true, then the default is "skipping". Unknown
values will cause git fetch to error out.
See also the --negotiate-only and --negotiation-tip options to git-
fetch(1).
fetch.showForcedUpdates
Set to false to enable git-fetch(1) and
git-pull(1) commands. Defaults to true.
fetch.parallel
Specifies the maximal number of fetch operations to be run in
parallel at a time (submodules, or remotes when the --multiple option
of git-fetch(1) is in effect).
A value of 0 will give some reasonable default. If unset, it defaults
to 1.
For submodules, this setting can be overridden using the
submodule.fetchJobs config setting.
fetch.writeCommitGraph
Set to true to write a commit-graph after every git fetch command
that downloads a pack-file from a remote. Using the --split option,
most executions will create a very small commit-graph file on top of
the existing commit-graph file(s). Occasionally, these files will
merge and the write may take longer. Having an updated commit-graph
file helps performance of many Git commands, including git
merge-base, git push -f, and git log --graph. Defaults to false.
fetch.bundleURI
This value stores a URI for downloading Git object data from a bundle
URI before performing an incremental fetch from the origin Git
server. This is similar to how the --bundle-uri option behaves in
git-clone(1). git clone --bundle-uri will set the fetch.bundleURI
value if the supplied bundle URI contains a bundle list that is
organized for incremental fetches.
If you modify this value and your repository has a
fetch.bundleCreationToken value, then remove that
fetch.bundleCreationToken value before fetching from the new bundle
URI.
fetch.bundleCreationToken
When using fetch.bundleURI to fetch incrementally from a bundle list
that uses the "creationToken" heuristic, this config value stores the
maximum creationToken value of the downloaded bundles. This value is
used to prevent downloading bundles in the future if the advertised
creationToken is not strictly larger than this value.
The creation token values are chosen by the provider serving the
specific bundle URI. If you modify the URI at fetch.bundleURI, then
be sure to remove the value for the fetch.bundleCreationToken value
before fetching.
BUGS
Using --recurse-submodules can only fetch new commits in submodules that
are present locally e.g. in $GIT_DIR/modules/. If the upstream adds a new
submodule, that submodule cannot be fetched until it is cloned e.g. by
git submodule update. This is expected to be fixed in a future Git
version.
SEE ALSO
git-pull(1)
GIT
Part of the git(1) suite
Git 2.40.0 03/13/2023 git-fetch(1)
git 2.40.0 - Generated Tue Mar 14 08:01:23 CDT 2023