Provided by: git-man_2.45.2-1ubuntu1_all 
NAME
git-receive-pack - Receive what is pushed into the repository
SYNOPSIS
git receive-pack <git-dir>
DESCRIPTION
Invoked by git send-pack and updates the repository with the information fed from the
remote end.
This command is usually not invoked directly by the end user. The UI for the protocol is
on the git send-pack side, and the program pair is meant to be used to push updates to a
remote repository. For pull operations, see git-fetch-pack(1).
The command allows for the creation and fast-forwarding of sha1 refs (heads/tags) on the
remote end (strictly speaking, it is the local end git-receive-pack runs, but to the user
who is sitting at the send-pack end, it is updating the remote. Confused?)
There are other real-world examples of using update and post-update hooks found in the
Documentation/howto directory.
git-receive-pack honours the receive.denyNonFastForwards config option, which tells it if
updates to a ref should be denied if they are not fast-forwards.
A number of other receive.* config options are available to tweak its behavior, see git-
config(1).
OPTIONS
<git-dir>
The repository to sync into.
--http-backend-info-refs
Used by git-http-backend(1) to serve up $GIT_URL/info/refs?service=git-receive-pack
requests. See --http-backend-info-refs in git-upload-pack(1).
PRE-RECEIVE HOOK
Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists and is executable, it
will be invoked once with no parameters. The standard input of the hook will be one line
per ref to be updated:
sha1-old SP sha1-new SP refname LF
The refname value is relative to $GIT_DIR; e.g. for the master head this is
"refs/heads/master". The two sha1 values before each refname are the object names for the
refname before and after the update. Refs to be created will have sha1-old equal to 0{40},
while refs to be deleted will have sha1-new equal to 0{40}, otherwise sha1-old and
sha1-new should be valid objects in the repository.
When accepting a signed push (see git-push(1)), the signed push certificate is stored in a
blob and an environment variable GIT_PUSH_CERT can be consulted for its object name. See
the description of post-receive hook for an example. In addition, the certificate is
verified using GPG and the result is exported with the following environment variables:
GIT_PUSH_CERT_SIGNER
The name and the e-mail address of the owner of the key that signed the push
certificate.
GIT_PUSH_CERT_KEY
The GPG key ID of the key that signed the push certificate.
GIT_PUSH_CERT_STATUS
The status of GPG verification of the push certificate, using the same mnemonic as
used in %G? format of git log family of commands (see git-log(1)).
GIT_PUSH_CERT_NONCE
The nonce string the process asked the signer to include in the push certificate. If
this does not match the value recorded on the "nonce" header in the push certificate,
it may indicate that the certificate is a valid one that is being replayed from a
separate "git push" session.
GIT_PUSH_CERT_NONCE_STATUS
UNSOLICITED
"git push --signed" sent a nonce when we did not ask it to send one.
MISSING
"git push --signed" did not send any nonce header.
BAD
"git push --signed" sent a bogus nonce.
OK
"git push --signed" sent the nonce we asked it to send.
SLOP
"git push --signed" sent a nonce different from what we asked it to send now, but
in a previous session. See GIT_PUSH_CERT_NONCE_SLOP environment variable.
GIT_PUSH_CERT_NONCE_SLOP
"git push --signed" sent a nonce different from what we asked it to send now, but in a
different session whose starting time is different by this many seconds from the
current session. Only meaningful when GIT_PUSH_CERT_NONCE_STATUS says SLOP. Also read
about receive.certNonceSlop variable in git-config(1).
This hook is called before any refname is updated and before any fast-forward checks are
performed.
If the pre-receive hook exits with a non-zero exit status no updates will be performed,
and the update, post-receive and post-update hooks will not be invoked either. This can be
useful to quickly bail out if the update is not to be supported.
See the notes on the quarantine environment below.
UPDATE HOOK
Before each ref is updated, if $GIT_DIR/hooks/update file exists and is executable, it is
invoked once per ref, with three parameters:
$GIT_DIR/hooks/update refname sha1-old sha1-new
The refname parameter is relative to $GIT_DIR; e.g. for the master head this is
"refs/heads/master". The two sha1 arguments are the object names for the refname before
and after the update. Note that the hook is called before the refname is updated, so
either sha1-old is 0{40} (meaning there is no such ref yet), or it should match what is
recorded in refname.
The hook should exit with non-zero status if it wants to disallow updating the named ref.
Otherwise it should exit with zero.
Successful execution (a zero exit status) of this hook does not ensure the ref will
actually be updated, it is only a prerequisite. As such it is not a good idea to send
notices (e.g. email) from this hook. Consider using the post-receive hook instead.
POST-RECEIVE HOOK
After all refs were updated (or attempted to be updated), if any ref update was
successful, and if $GIT_DIR/hooks/post-receive file exists and is executable, it will be
invoked once with no parameters. The standard input of the hook will be one line for each
successfully updated ref:
sha1-old SP sha1-new SP refname LF
The refname value is relative to $GIT_DIR; e.g. for the master head this is
"refs/heads/master". The two sha1 values before each refname are the object names for the
refname before and after the update. Refs that were created will have sha1-old equal to
0{40}, while refs that were deleted will have sha1-new equal to 0{40}, otherwise sha1-old
and sha1-new should be valid objects in the repository.
The GIT_PUSH_CERT* environment variables can be inspected, just as in pre-receive hook,
after accepting a signed push.
Using this hook, it is easy to generate mails describing the updates to the repository.
This example script sends one mail message per ref listing the commits pushed to the
repository, and logs the push certificates of signed pushes with good signatures to a
logger service:
#!/bin/sh
# mail out commit update information.
while read oval nval ref
do
if expr "$oval" : '0*$' >/dev/null
then
echo "Created a new ref, with the following commits:"
git rev-list --pretty "$nval"
else
echo "New commits:"
git rev-list --pretty "$nval" "^$oval"
fi |
mail -s "Changes to ref $ref" commit-list@mydomain
done
# log signed push certificate, if any
if test -n "${GIT_PUSH_CERT-}" && test ${GIT_PUSH_CERT_STATUS} = G
then
(
echo expected nonce is ${GIT_PUSH_NONCE}
git cat-file blob ${GIT_PUSH_CERT}
) | mail -s "push certificate from $GIT_PUSH_CERT_SIGNER" push-log@mydomain
fi
exit 0
The exit code from this hook invocation is ignored, however a non-zero exit code will
generate an error message.
Note that it is possible for refname to not have sha1-new when this hook runs. This can
easily occur if another user modifies the ref after it was updated by git-receive-pack,
but before the hook was able to evaluate it. It is recommended that hooks rely on sha1-new
rather than the current value of refname.
POST-UPDATE HOOK
After all other processing, if at least one ref was updated, and if
$GIT_DIR/hooks/post-update file exists and is executable, then post-update will be called
with the list of refs that have been updated. This can be used to implement any repository
wide cleanup tasks.
The exit code from this hook invocation is ignored; the only thing left for
git-receive-pack to do at that point is to exit itself anyway.
This hook can be used, for example, to run git update-server-info if the repository is
packed and is served via a dumb transport.
#!/bin/sh
exec git update-server-info
QUARANTINE ENVIRONMENT
When receive-pack takes in objects, they are placed into a temporary "quarantine"
directory within the $GIT_DIR/objects directory and migrated into the main object store
only after the pre-receive hook has completed. If the push fails before then, the
temporary directory is removed entirely.
This has a few user-visible effects and caveats:
1. Pushes which fail due to problems with the incoming pack, missing objects, or due to
the pre-receive hook will not leave any on-disk data. This is usually helpful to
prevent repeated failed pushes from filling up your disk, but can make debugging more
challenging.
2. Any objects created by the pre-receive hook will be created in the quarantine
directory (and migrated only if it succeeds).
3. The pre-receive hook MUST NOT update any refs to point to quarantined objects. Other
programs accessing the repository will not be able to see the objects (and if the
pre-receive hook fails, those refs would become corrupted). For safety, any ref
updates from within pre-receive are automatically rejected.
SEE ALSO
git-send-pack(1), gitnamespaces(7)
GIT
Part of the git(1) suite