Documentation / git-receive-pack.txton commit remote: add promisor and partial clone config to the doc (75de085)
   1git-receive-pack(1)
   2===================
   3
   4NAME
   5----
   6git-receive-pack - Receive what is pushed into the repository
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git-receive-pack' <directory>
  13
  14DESCRIPTION
  15-----------
  16Invoked by 'git send-pack' and updates the repository with the
  17information fed from the remote end.
  18
  19This command is usually not invoked directly by the end user.
  20The UI for the protocol is on the 'git send-pack' side, and the
  21program pair is meant to be used to push updates to remote
  22repository.  For pull operations, see linkgit:git-fetch-pack[1].
  23
  24The command allows for creation and fast-forwarding of sha1 refs
  25(heads/tags) on the remote end (strictly speaking, it is the
  26local end 'git-receive-pack' runs, but to the user who is sitting at
  27the send-pack end, it is updating the remote.  Confused?)
  28
  29There are other real-world examples of using update and
  30post-update hooks found in the Documentation/howto directory.
  31
  32'git-receive-pack' honours the receive.denyNonFastForwards config
  33option, which tells it if updates to a ref should be denied if they
  34are not fast-forwards.
  35
  36A number of other receive.* config options are available to tweak
  37its behavior, see linkgit:git-config[1].
  38
  39OPTIONS
  40-------
  41<directory>::
  42        The repository to sync into.
  43
  44PRE-RECEIVE HOOK
  45----------------
  46Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
  47and is executable, it will be invoked once with no parameters.  The
  48standard input of the hook will be one line per ref to be updated:
  49
  50       sha1-old SP sha1-new SP refname LF
  51
  52The refname value is relative to $GIT_DIR; e.g. for the master
  53head this is "refs/heads/master".  The two sha1 values before
  54each refname are the object names for the refname before and after
  55the update.  Refs to be created will have sha1-old equal to 0\{40},
  56while refs to be deleted will have sha1-new equal to 0\{40}, otherwise
  57sha1-old and sha1-new should be valid objects in the repository.
  58
  59When accepting a signed push (see linkgit:git-push[1]), the signed
  60push certificate is stored in a blob and an environment variable
  61`GIT_PUSH_CERT` can be consulted for its object name.  See the
  62description of `post-receive` hook for an example.  In addition, the
  63certificate is verified using GPG and the result is exported with
  64the following environment variables:
  65
  66`GIT_PUSH_CERT_SIGNER`::
  67        The name and the e-mail address of the owner of the key that
  68        signed the push certificate.
  69
  70`GIT_PUSH_CERT_KEY`::
  71        The GPG key ID of the key that signed the push certificate.
  72
  73`GIT_PUSH_CERT_STATUS`::
  74        The status of GPG verification of the push certificate,
  75        using the same mnemonic as used in `%G?` format of `git log`
  76        family of commands (see linkgit:git-log[1]).
  77
  78`GIT_PUSH_CERT_NONCE`::
  79        The nonce string the process asked the signer to include
  80        in the push certificate.  If this does not match the value
  81        recorded on the "nonce" header in the push certificate, it
  82        may indicate that the certificate is a valid one that is
  83        being replayed from a separate "git push" session.
  84
  85`GIT_PUSH_CERT_NONCE_STATUS`::
  86`UNSOLICITED`;;
  87        "git push --signed" sent a nonce when we did not ask it to
  88        send one.
  89`MISSING`;;
  90        "git push --signed" did not send any nonce header.
  91`BAD`;;
  92        "git push --signed" sent a bogus nonce.
  93`OK`;;
  94        "git push --signed" sent the nonce we asked it to send.
  95`SLOP`;;
  96        "git push --signed" sent a nonce different from what we
  97        asked it to send now, but in a previous session.  See
  98        `GIT_PUSH_CERT_NONCE_SLOP` environment variable.
  99
 100`GIT_PUSH_CERT_NONCE_SLOP`::
 101        "git push --signed" sent a nonce different from what we
 102        asked it to send now, but in a different session whose
 103        starting time is different by this many seconds from the
 104        current session.  Only meaningful when
 105        `GIT_PUSH_CERT_NONCE_STATUS` says `SLOP`.
 106        Also read about `receive.certNonceSlop` variable in
 107        linkgit:git-config[1].
 108
 109This hook is called before any refname is updated and before any
 110fast-forward checks are performed.
 111
 112If the pre-receive hook exits with a non-zero exit status no updates
 113will be performed, and the update, post-receive and post-update
 114hooks will not be invoked either.  This can be useful to quickly
 115bail out if the update is not to be supported.
 116
 117See the notes on the quarantine environment below.
 118
 119UPDATE HOOK
 120-----------
 121Before each ref is updated, if $GIT_DIR/hooks/update file exists
 122and is executable, it is invoked once per ref, with three parameters:
 123
 124       $GIT_DIR/hooks/update refname sha1-old sha1-new
 125
 126The refname parameter is relative to $GIT_DIR; e.g. for the master
 127head this is "refs/heads/master".  The two sha1 arguments are
 128the object names for the refname before and after the update.
 129Note that the hook is called before the refname is updated,
 130so either sha1-old is 0\{40} (meaning there is no such ref yet),
 131or it should match what is recorded in refname.
 132
 133The hook should exit with non-zero status if it wants to disallow
 134updating the named ref.  Otherwise it should exit with zero.
 135
 136Successful execution (a zero exit status) of this hook does not
 137ensure the ref will actually be updated, it is only a prerequisite.
 138As such it is not a good idea to send notices (e.g. email) from
 139this hook.  Consider using the post-receive hook instead.
 140
 141POST-RECEIVE HOOK
 142-----------------
 143After all refs were updated (or attempted to be updated), if any
 144ref update was successful, and if $GIT_DIR/hooks/post-receive
 145file exists and is executable, it will be invoked once with no
 146parameters.  The standard input of the hook will be one line
 147for each successfully updated ref:
 148
 149       sha1-old SP sha1-new SP refname LF
 150
 151The refname value is relative to $GIT_DIR; e.g. for the master
 152head this is "refs/heads/master".  The two sha1 values before
 153each refname are the object names for the refname before and after
 154the update.  Refs that were created will have sha1-old equal to
 1550\{40}, while refs that were deleted will have sha1-new equal to
 1560\{40}, otherwise sha1-old and sha1-new should be valid objects in
 157the repository.
 158
 159The `GIT_PUSH_CERT*` environment variables can be inspected, just as
 160in `pre-receive` hook, after accepting a signed push.
 161
 162Using this hook, it is easy to generate mails describing the updates
 163to the repository.  This example script sends one mail message per
 164ref listing the commits pushed to the repository, and logs the push
 165certificates of signed pushes with good signatures to a logger
 166service:
 167
 168        #!/bin/sh
 169        # mail out commit update information.
 170        while read oval nval ref
 171        do
 172                if expr "$oval" : '0*$' >/dev/null
 173                then
 174                        echo "Created a new ref, with the following commits:"
 175                        git rev-list --pretty "$nval"
 176                else
 177                        echo "New commits:"
 178                        git rev-list --pretty "$nval" "^$oval"
 179                fi |
 180                mail -s "Changes to ref $ref" commit-list@mydomain
 181        done
 182        # log signed push certificate, if any
 183        if test -n "${GIT_PUSH_CERT-}" && test ${GIT_PUSH_CERT_STATUS} = G
 184        then
 185                (
 186                        echo expected nonce is ${GIT_PUSH_NONCE}
 187                        git cat-file blob ${GIT_PUSH_CERT}
 188                ) | mail -s "push certificate from $GIT_PUSH_CERT_SIGNER" push-log@mydomain
 189        fi
 190        exit 0
 191
 192The exit code from this hook invocation is ignored, however a
 193non-zero exit code will generate an error message.
 194
 195Note that it is possible for refname to not have sha1-new when this
 196hook runs.  This can easily occur if another user modifies the ref
 197after it was updated by 'git-receive-pack', but before the hook was able
 198to evaluate it.  It is recommended that hooks rely on sha1-new
 199rather than the current value of refname.
 200
 201POST-UPDATE HOOK
 202----------------
 203After all other processing, if at least one ref was updated, and
 204if $GIT_DIR/hooks/post-update file exists and is executable, then
 205post-update will be called with the list of refs that have been updated.
 206This can be used to implement any repository wide cleanup tasks.
 207
 208The exit code from this hook invocation is ignored; the only thing
 209left for 'git-receive-pack' to do at that point is to exit itself
 210anyway.
 211
 212This hook can be used, for example, to run `git update-server-info`
 213if the repository is packed and is served via a dumb transport.
 214
 215        #!/bin/sh
 216        exec git update-server-info
 217
 218
 219QUARANTINE ENVIRONMENT
 220----------------------
 221
 222When `receive-pack` takes in objects, they are placed into a temporary
 223"quarantine" directory within the `$GIT_DIR/objects` directory and
 224migrated into the main object store only after the `pre-receive` hook
 225has completed. If the push fails before then, the temporary directory is
 226removed entirely.
 227
 228This has a few user-visible effects and caveats:
 229
 230  1. Pushes which fail due to problems with the incoming pack, missing
 231     objects, or due to the `pre-receive` hook will not leave any
 232     on-disk data. This is usually helpful to prevent repeated failed
 233     pushes from filling up your disk, but can make debugging more
 234     challenging.
 235
 236  2. Any objects created by the `pre-receive` hook will be created in
 237     the quarantine directory (and migrated only if it succeeds).
 238
 239  3. The `pre-receive` hook MUST NOT update any refs to point to
 240     quarantined objects. Other programs accessing the repository will
 241     not be able to see the objects (and if the pre-receive hook fails,
 242     those refs would become corrupted). For safety, any ref updates
 243     from within `pre-receive` are automatically rejected.
 244
 245
 246SEE ALSO
 247--------
 248linkgit:git-send-pack[1], linkgit:gitnamespaces[7]
 249
 250GIT
 251---
 252Part of the linkgit:git[1] suite