Commands are given by the caller on the helper's standard input,
one per line.
capabilities
Lists the capabilities of the helper, one per line, ending
with a blank line. Each capability may be preceded with *,
which marks them mandatory for Git versions using the remote
helper to understand. Any unknown mandatory capability is a
fatal error.
Support for this command is mandatory.
list
Lists the refs, one per line, in the format "<value> <name>
[<attr> ...]". The value may be a hex sha1 hash, "@<dest>"
for a symref, ":<keyword> <value>" for a key-value pair, or
"?" to indicate that the helper could not get the value of
the ref. A space-separated list of attributes follows the
name; unrecognized attributes are ignored. The list ends with
a blank line.
See REF LIST ATTRIBUTES for a list of currently defined
attributes. See REF LIST KEYWORDS for a list of currently
defined keywords.
Supported if the helper has the "fetch" or "import"
capability.
list for-push
Similar to list, except that it is used if and only if the
caller wants to the resulting ref list to prepare push
commands. A helper supporting both push and fetch can use
this to distinguish for which operation the output of list is
going to be used, possibly reducing the amount of work that
needs to be performed.
Supported if the helper has the "push" or "export"
capability.
option <name> <value>
Sets the transport helper option <name> to <value>. Outputs a
single line containing one of ok (option successfully set),
unsupported (option not recognized) or error <msg> (option
<name> is supported but <value> is not valid for it). Options
should be set before other commands, and may influence the
behavior of those commands.
See OPTIONS for a list of currently defined options.
Supported if the helper has the "option" capability.
fetch <sha1> <name>
Fetches the given object, writing the necessary objects to
the database. Fetch commands are sent in a batch, one per
line, terminated with a blank line. Outputs a single blank
line when all fetch commands in the same batch are complete.
Only objects which were reported in the output of list with a
sha1 may be fetched this way.
Optionally may output a lock <file> line indicating the full
path of a file under $GIT_DIR/objects/pack which is keeping a
pack until refs can be suitably updated. The path must end
with .keep. This is a mechanism to name a <pack,idx,keep>
tuple by giving only the keep component. The kept pack will
not be deleted by a concurrent repack, even though its
objects may not be referenced until the fetch completes. The
.keep file will be deleted at the conclusion of the fetch.
If option check-connectivity is requested, the helper must
output connectivity-ok if the clone is self-contained and
connected.
Supported if the helper has the "fetch" capability.
push +<src>:<dst>
Pushes the given local <src> commit or branch to the remote
branch described by <dst>. A batch sequence of one or more
push commands is terminated with a blank line (if there is
only one reference to push, a single push command is followed
by a blank line). For example, the following would be two
batches of push, the first asking the remote-helper to push
the local ref master to the remote ref master and the local
HEAD to the remote branch, and the second asking to push ref
foo to ref bar (forced update requested by the +).
push refs/heads/master:refs/heads/master
push HEAD:refs/heads/branch
\n
push +refs/heads/foo:refs/heads/bar
\n
Zero or more protocol options may be entered after the last
push command, before the batch's terminating blank line.
When the push is complete, outputs one or more ok <dst> or
error <dst> <why>? lines to indicate success or failure of
each pushed ref. The status report output is terminated by a
blank line. The option field <why> may be quoted in a C style
string if it contains an LF.
Supported if the helper has the "push" capability.
import <name>
Produces a fast-import stream which imports the current value
of the named ref. It may additionally import other refs as
needed to construct the history efficiently. The script
writes to a helper-specific private namespace. The value of
the named ref should be written to a location in this
namespace derived by applying the refspecs from the "refspec"
capability to the name of the ref.
Especially useful for interoperability with a foreign
versioning system.
Just like push, a batch sequence of one or more import is
terminated with a blank line. For each batch of import, the
remote helper should produce a fast-import stream terminated
by a done command.
Note that if the bidi-import capability is used the complete
batch sequence has to be buffered before starting to send
data to fast-import to prevent mixing of commands and
fast-import responses on the helper's stdin.
Supported if the helper has the "import" capability.
export
Instructs the remote helper that any subsequent input is part
of a fast-import stream (generated by git fast-export)
containing objects which should be pushed to the remote.
Especially useful for interoperability with a foreign
versioning system.
The export-marks and import-marks capabilities, if specified,
affect this command in so far as they are passed on to git
fast-export, which then will load/store a table of marks for
local objects. This can be used to implement for incremental
operations.
Supported if the helper has the "export" capability.
connect <service>
Connects to given service. Standard input and standard output
of helper are connected to specified service (git prefix is
included in service name so e.g. fetching uses
git-upload-pack as service) on remote side. Valid replies to
this command are empty line (connection established),
fallback (no smart transport support, fall back to dumb
transports) and just exiting with error message printed
(can't connect, don't bother trying to fall back). After line
feed terminating the positive (empty) response, the output of
service starts. After the connection ends, the remote helper
exits.
Supported if the helper has the "connect" capability.
stateless-connect <service>
Experimental; for internal use only. Connects to the given
remote service for communication using git's wire-protocol
version 2. Valid replies to this command are empty line
(connection established), fallback (no smart transport
support, fall back to dumb transports) and just exiting with
error message printed (can't connect, don't bother trying to
fall back). After line feed terminating the positive (empty)
response, the output of the service starts. Messages (both
request and response) must consist of zero or more PKT-LINEs,
terminating in a flush packet. Response messages will then
have a response end packet after the flush packet to indicate
the end of a response. The client must not expect the server
to store any state in between request-response pairs. After
the connection ends, the remote helper exits.
Supported if the helper has the "stateless-connect"
capability.
If a fatal error occurs, the program writes the error message to
stderr and exits. The caller should expect that a suitable error
message has been printed if the child closes the connection
without completing a valid response for the current command.
Additional commands may be supported, as may be determined from
capabilities reported by the helper.
