gitprotocol-v2(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | PACKET-LINE FRAMING | INITIAL CLIENT REQUEST | CAPABILITY ADVERTISEMENT | COMMAND REQUEST | CAPABILITIES | GIT | NOTES | COLOPHON

GITPROTOCOL-V2(5)              Git Manual              GITPROTOCOL-V2(5)

NAME         top

       gitprotocol-v2 - Git Wire Protocol, Version 2

SYNOPSIS         top

       <over-the-wire-protocol>

DESCRIPTION         top

       This document presents a specification for a version 2 of Git’s
       wire protocol. Protocol v2 will improve upon v1 in the following
       ways:

       •   Instead of multiple service names, multiple commands will be
           supported by a single service

       •   Easily extendable as capabilities are moved into their own
           section of the protocol, no longer being hidden behind a NUL
           byte and limited by the size of a pkt-line

       •   Separate out other information hidden behind NUL bytes (e.g.
           agent string as a capability and symrefs can be requested
           using ls-refs)

       •   Reference advertisement will be omitted unless explicitly
           requested

       •   ls-refs command to explicitly request some refs

       •   Designed with http and stateless-rpc in mind. With clear
           flush semantics the http remote helper can simply act as a
           proxy

       In protocol v2 communication is command oriented. When first
       contacting a server a list of capabilities will be advertised.
       Some of these capabilities will be commands which a client can
       request be executed. Once a command has completed, a client can
       reuse the connection and request that other commands be executed.

PACKET-LINE FRAMING         top

       All communication is done using packet-line framing, just as in
       v1. See gitprotocol-pack(5) and gitprotocol-common(5) for more
       information.

       In protocol v2 these special packets will have the following
       semantics:

       •   0000 Flush Packet (flush-pkt) - indicates the end of a
           message

       •   0001 Delimiter Packet (delim-pkt) - separates sections of a
           message

       •   0002 Response End Packet (response-end-pkt) - indicates the
           end of a response for stateless connections

INITIAL CLIENT REQUEST         top

       In general a client can request to speak protocol v2 by sending
       version=2 through the respective side-channel for the transport
       being used which inevitably sets GIT_PROTOCOL. More information
       can be found in gitprotocol-pack(5) and gitprotocol-http(5), as
       well as the GIT_PROTOCOL definition in git.txt. In all cases the
       response from the server is the capability advertisement.

   Git Transport
       When using the git:// transport, you can request to use protocol
       v2 by sending "version=2" as an extra parameter:

           003egit-upload-pack /project.git\0host=myserver.com\0\0version=2\0

   SSH and File Transport
       When using either the ssh:// or file:// transport, the
       GIT_PROTOCOL environment variable must be set explicitly to
       include "version=2". The server may need to be configured to
       allow this environment variable to pass.

   HTTP Transport
       When using the http:// or https:// transport a client makes a
       "smart" info/refs request as described in gitprotocol-http(5) and
       requests that v2 be used by supplying "version=2" in the
       Git-Protocol header.

           C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0
           C: Git-Protocol: version=2

       A v2 server would reply:

           S: 200 OK
           S: <Some headers>
           S: ...
           S:
           S: 000eversion 2\n
           S: <capability-advertisement>

       Subsequent requests are then made directly to the service
       $GIT_URL/git-upload-pack. (This works the same for
       git-receive-pack).

       Uses the --http-backend-info-refs option to git-upload-pack(1).

       The server may need to be configured to pass this header’s
       contents via the GIT_PROTOCOL variable. See the discussion in
       git-http-backend.txt.

CAPABILITY ADVERTISEMENT         top

       A server which decides to communicate (based on a request from a
       client) using protocol version 2, notifies the client by sending
       a version string in its initial response followed by an
       advertisement of its capabilities. Each capability is a key with
       an optional value. Clients must ignore all unknown keys.
       Semantics of unknown values are left to the definition of each
       key. Some capabilities will describe commands which can be
       requested to be executed by the client.

           capability-advertisement = protocol-version
                                      capability-list
                                      flush-pkt

           protocol-version = PKT-LINE("version 2" LF)
           capability-list = *capability
           capability = PKT-LINE(key[=value] LF)

           key = 1*(ALPHA | DIGIT | "-_")
           value = 1*(ALPHA | DIGIT | " -_.,?\/{}[]()<>!@#$%^&*+=:;")

COMMAND REQUEST         top

       After receiving the capability advertisement, a client can then
       issue a request to select the command it wants with any
       particular capabilities or arguments. There is then an optional
       section where the client can provide any command specific
       parameters or queries. Only a single command can be requested at
       a time.

           request = empty-request | command-request
           empty-request = flush-pkt
           command-request = command
                             capability-list
                             delim-pkt
                             command-args
                             flush-pkt
           command = PKT-LINE("command=" key LF)
           command-args = *command-specific-arg

           command-specific-args are packet line framed arguments defined by
           each individual command.

       The server will then check to ensure that the client’s request is
       comprised of a valid command as well as valid capabilities which
       were advertised. If the request is valid the server will then
       execute the command. A server MUST wait till it has received the
       client’s entire request before issuing a response. The format of
       the response is determined by the command being executed, but in
       all cases a flush-pkt indicates the end of the response.

       When a command has finished, and the client has received the
       entire response from the server, a client can either request that
       another command be executed or can terminate the connection. A
       client may optionally send an empty request consisting of just a
       flush-pkt to indicate that no more requests will be made.

CAPABILITIES         top

       There are two different types of capabilities: normal
       capabilities, which can be used to convey information or alter
       the behavior of a request, and commands, which are the core
       actions that a client wants to perform (fetch, push, etc).

       Protocol version 2 is stateless by default. This means that all
       commands must only last a single round and be stateless from the
       perspective of the server side, unless the client has requested a
       capability indicating that state should be maintained by the
       server. Clients MUST NOT require state management on the server
       side in order to function correctly. This permits simple
       round-robin load-balancing on the server side, without needing to
       worry about state management.

   agent
       The server can advertise the agent capability with a value X (in
       the form agent=X) to notify the client that the server is running
       version X. The client may optionally send its own agent string by
       including the agent capability with a value Y (in the form
       agent=Y) in its request to the server (but it MUST NOT do so if
       the server did not advertise the agent capability). The X and Y
       strings may contain any printable ASCII characters except space
       (i.e., the byte range 32 < x < 127), and are typically of the
       form "package/version" (e.g., "git/1.8.3.1"). The agent strings
       are purely informative for statistics and debugging purposes, and
       MUST NOT be used to programmatically assume the presence or
       absence of particular features.

   ls-refs
       ls-refs is the command used to request a reference advertisement
       in v2. Unlike the current reference advertisement, ls-refs takes
       in arguments which can be used to limit the refs sent from the
       server.

       Additional features not supported in the base command will be
       advertised as the value of the command in the capability
       advertisement in the form of a space separated list of features:
       "<command>=<feature-1> <feature-2>"

       ls-refs takes in the following arguments:

           symrefs
               In addition to the object pointed by it, show the underlying ref
               pointed by it when showing a symbolic ref.
           peel
               Show peeled tags.
           ref-prefix <prefix>
               When specified, only references having a prefix matching one of
               the provided prefixes are displayed. Multiple instances may be
               given, in which case references matching any prefix will be
               shown. Note that this is purely for optimization; a server MAY
               show refs not matching the prefix if it chooses, and clients
               should filter the result themselves.

       If the unborn feature is advertised the following argument can be
       included in the client’s request.

           unborn
               The server will send information about HEAD even if it is a symref
               pointing to an unborn branch in the form "unborn HEAD
               symref-target:<target>".

       The output of ls-refs is as follows:

           output = *ref
                    flush-pkt
           obj-id-or-unborn = (obj-id | "unborn")
           ref = PKT-LINE(obj-id-or-unborn SP refname *(SP ref-attribute) LF)
           ref-attribute = (symref | peeled)
           symref = "symref-target:" symref-target
           peeled = "peeled:" obj-id

   fetch
       fetch is the command used to fetch a packfile in v2. It can be
       looked at as a modified version of the v1 fetch where the
       ref-advertisement is stripped out (since the ls-refs command
       fills that role) and the message format is tweaked to eliminate
       redundancies and permit easy addition of future extensions.

       Additional features not supported in the base command will be
       advertised as the value of the command in the capability
       advertisement in the form of a space separated list of features:
       "<command>=<feature-1> <feature-2>"

       A fetch request can take the following arguments:

           want <oid>
               Indicates to the server an object which the client wants to
               retrieve.  Wants can be anything and are not limited to
               advertised objects.

           have <oid>
               Indicates to the server an object which the client has locally.
               This allows the server to make a packfile which only contains
               the objects that the client needs. Multiple 'have' lines can be
               supplied.

           done
               Indicates to the server that negotiation should terminate (or
               not even begin if performing a clone) and that the server should
               use the information supplied in the request to construct the
               packfile.

           thin-pack
               Request that a thin pack be sent, which is a pack with deltas
               which reference base objects not contained within the pack (but
               are known to exist at the receiving end). This can reduce the
               network traffic significantly, but it requires the receiving end
               to know how to "thicken" these packs by adding the missing bases
               to the pack.

           no-progress
               Request that progress information that would normally be sent on
               side-band channel 2, during the packfile transfer, should not be
               sent.  However, the side-band channel 3 is still used for error
               responses.

           include-tag
               Request that annotated tags should be sent if the objects they
               point to are being sent.

           ofs-delta
               Indicate that the client understands PACKv2 with delta referring
               to its base by position in pack rather than by an oid.  That is,
               they can read OBJ_OFS_DELTA (aka type 6) in a packfile.

       If the shallow feature is advertised the following arguments can
       be included in the clients request as well as the potential
       addition of the shallow-info section in the server’s response as
       explained below.

           shallow <oid>
               A client must notify the server of all commits for which it only
               has shallow copies (meaning that it doesn't have the parents of
               a commit) by supplying a 'shallow <oid>' line for each such
               object so that the server is aware of the limitations of the
               client's history.  This is so that the server is aware that the
               client may not have all objects reachable from such commits.

           deepen <depth>
               Requests that the fetch/clone should be shallow having a commit
               depth of <depth> relative to the remote side.

           deepen-relative
               Requests that the semantics of the "deepen" command be changed
               to indicate that the depth requested is relative to the client's
               current shallow boundary, instead of relative to the requested
               commits.

           deepen-since <timestamp>
               Requests that the shallow clone/fetch should be cut at a
               specific time, instead of depth.  Internally it's equivalent to
               doing "git rev-list --max-age=<timestamp>". Cannot be used with
               "deepen".

           deepen-not <rev>
               Requests that the shallow clone/fetch should be cut at a
               specific revision specified by '<rev>', instead of a depth.
               Internally it's equivalent of doing "git rev-list --not <rev>".
               Cannot be used with "deepen", but can be used with
               "deepen-since".

       If the filter feature is advertised, the following argument can
       be included in the client’s request:

           filter <filter-spec>
               Request that various objects from the packfile be omitted
               using one of several filtering techniques. These are intended
               for use with partial clone and partial fetch operations. See
               `rev-list` for possible "filter-spec" values. When communicating
               with other processes, senders SHOULD translate scaled integers
               (e.g. "1k") into a fully-expanded form (e.g. "1024") to aid
               interoperability with older receivers that may not understand
               newly-invented scaling suffixes. However, receivers SHOULD
               accept the following suffixes: 'k', 'm', and 'g' for 1024,
               1048576, and 1073741824, respectively.

       If the ref-in-want feature is advertised, the following argument
       can be included in the client’s request as well as the potential
       addition of the wanted-refs section in the server’s response as
       explained below.

           want-ref <ref>
               Indicates to the server that the client wants to retrieve a
               particular ref, where <ref> is the full name of a ref on the
               server.  It is a protocol error to send want-ref for the
               same ref more than once.

       If the sideband-all feature is advertised, the following argument
       can be included in the client’s request:

           sideband-all
               Instruct the server to send the whole response multiplexed, not just
               the packfile section. All non-flush and non-delim PKT-LINE in the
               response (not only in the packfile section) will then start with a byte
               indicating its sideband (1, 2, or 3), and the server may send "0005\2"
               (a PKT-LINE of sideband 2 with no payload) as a keepalive packet.

       If the packfile-uris feature is advertised, the following
       argument can be included in the client’s request as well as the
       potential addition of the packfile-uris section in the server’s
       response as explained below. Note that at most one packfile-uris
       line can be sent to the server.

           packfile-uris <comma-separated-list-of-protocols>
               Indicates to the server that the client is willing to receive
               URIs of any of the given protocols in place of objects in the
               sent packfile. Before performing the connectivity check, the
               client should download from all given URIs. Currently, the
               protocols supported are "http" and "https".

       If the wait-for-done feature is advertised, the following
       argument can be included in the client’s request.

           wait-for-done
               Indicates to the server that it should never send "ready", but
               should wait for the client to say "done" before sending the
               packfile.

       The response of fetch is broken into a number of sections
       separated by delimiter packets (0001), with each section
       beginning with its section header. Most sections are sent only
       when the packfile is sent.

           output = acknowledgements flush-pkt |
                    [acknowledgments delim-pkt] [shallow-info delim-pkt]
                    [wanted-refs delim-pkt] [packfile-uris delim-pkt]
                    packfile flush-pkt

           acknowledgments = PKT-LINE("acknowledgments" LF)
                             (nak | *ack)
                             (ready)
           ready = PKT-LINE("ready" LF)
           nak = PKT-LINE("NAK" LF)
           ack = PKT-LINE("ACK" SP obj-id LF)

           shallow-info = PKT-LINE("shallow-info" LF)
                          *PKT-LINE((shallow | unshallow) LF)
           shallow = "shallow" SP obj-id
           unshallow = "unshallow" SP obj-id

           wanted-refs = PKT-LINE("wanted-refs" LF)
                         *PKT-LINE(wanted-ref LF)
           wanted-ref = obj-id SP refname

           packfile-uris = PKT-LINE("packfile-uris" LF) *packfile-uri
           packfile-uri = PKT-LINE(40*(HEXDIGIT) SP *%x20-ff LF)

           packfile = PKT-LINE("packfile" LF)
                      *PKT-LINE(%x01-03 *%x00-ff)

           acknowledgments section
               * If the client determines that it is finished with negotiations by
                 sending a "done" line (thus requiring the server to send a packfile),
                 the acknowledgments sections MUST be omitted from the server's
                 response.

       •   Always begins with the section header "acknowledgments"

       •   The server will respond with "NAK" if none of the object ids
           sent as have lines were common.

       •   The server will respond with "ACK obj-id" for all of the
           object ids sent as have lines which are common.

       •   A response cannot have both "ACK" lines as well as a "NAK"
           line.

       •   The server will respond with a "ready" line indicating that
           the server has found an acceptable common base and is ready
           to make and send a packfile (which will be found in the
           packfile section of the same response)

       •   If the server has found a suitable cut point and has decided
           to send a "ready" line, then the server can decide to (as an
           optimization) omit any "ACK" lines it would have sent during
           its response. This is because the server will have already
           determined the objects it plans to send to the client and no
           further negotiation is needed.

               shallow-info section
                   * If the client has requested a shallow fetch/clone, a shallow
                     client requests a fetch or the server is shallow then the
                     server's response may include a shallow-info section.  The
                     shallow-info section will be included if (due to one of the
                     above conditions) the server needs to inform the client of any
                     shallow boundaries or adjustments to the clients already
                     existing shallow boundaries.

       •   Always begins with the section header "shallow-info"

       •   If a positive depth is requested, the server will compute the
           set of commits which are no deeper than the desired depth.

       •   The server sends a "shallow obj-id" line for each commit
           whose parents will not be sent in the following packfile.

       •   The server sends an "unshallow obj-id" line for each commit
           which the client has indicated is shallow, but is no longer
           shallow as a result of the fetch (due to its parents being
           sent in the following packfile).

       •   The server MUST NOT send any "unshallow" lines for anything
           which the client has not indicated was shallow as a part of
           its request.

               wanted-refs section
                   * This section is only included if the client has requested a
                     ref using a 'want-ref' line and if a packfile section is also
                     included in the response.

       •   Always begins with the section header "wanted-refs".

       •   The server will send a ref listing ("<oid> <refname>") for
           each reference requested using want-ref lines.

       •   The server MUST NOT send any refs which were not requested
           using want-ref lines.

               packfile-uris section
                   * This section is only included if the client sent
                     'packfile-uris' and the server has at least one such URI to
                     send.

       •   Always begins with the section header "packfile-uris".

       •   For each URI the server sends, it sends a hash of the pack’s
           contents (as output by git index-pack) followed by the URI.

       •   The hashes are 40 hex characters long. When Git upgrades to a
           new hash algorithm, this might need to be updated. (It should
           match whatever index-pack outputs after "pack\t" or "keep\t".

               packfile section
                   * This section is only included if the client has sent 'want'
                     lines in its request and either requested that no more
                     negotiation be done by sending 'done' or if the server has
                     decided it has found a sufficient cut point to produce a
                     packfile.

       •   Always begins with the section header "packfile"

       •   The transmission of the packfile begins immediately after the
           section header

       •   The data transfer of the packfile is always multiplexed,
           using the same semantics of the side-band-64k capability from
           protocol version 1. This means that each packet, during the
           packfile data stream, is made up of a leading 4-byte pkt-line
           length (typical of the pkt-line format), followed by a 1-byte
           stream code, followed by the actual data.

               The stream code can be one of:
                     1 - pack data
                     2 - progress messages
                     3 - fatal error message just before stream aborts

   server-option
       If advertised, indicates that any number of server specific
       options can be included in a request. This is done by sending
       each option as a "server-option=<option>" capability line in the
       capability-list section of a request.

       The provided options must not contain a NUL or LF character.

   object-format
       The server can advertise the object-format capability with a
       value X (in the form object-format=X) to notify the client that
       the server is able to deal with objects using hash algorithm X.
       If not specified, the server is assumed to only handle SHA-1. If
       the client would like to use a hash algorithm other than SHA-1,
       it should specify its object-format string.

   session-id=<session-id>
       The server may advertise a session ID that can be used to
       identify this process across multiple requests. The client may
       advertise its own session ID back to the server as well.

       Session IDs should be unique to a given process. They must fit
       within a packet-line, and must not contain non-printable or
       whitespace characters. The current implementation uses trace2
       session IDs (see api-trace2[1] for details), but this may change
       and users of the session ID should not rely on this fact.

   object-info
       object-info is the command to retrieve information about one or
       more objects. Its main purpose is to allow a client to make
       decisions based on this information without having to fully fetch
       objects. Object size is the only information that is currently
       supported.

       An object-info request takes the following arguments:

           size
           Requests size information to be returned for each listed object id.

           oid <oid>
           Indicates to the server an object which the client wants to obtain
           information for.

       The response of object-info is a list of the requested object ids
       and associated requested information, each separated by a single
       space.

           output = info flush-pkt

           info = PKT-LINE(attrs) LF)
                   *PKT-LINE(obj-info LF)

           attrs = attr | attrs SP attrs

           attr = "size"

           obj-info = obj-id SP obj-size

   bundle-uri
       If the bundle-uri capability is advertised, the server supports
       the ‘bundle-uri’ command.

       The capability is currently advertised with no value (i.e. not
       "bundle-uri=somevalue"), a value may be added in the future for
       supporting command-wide extensions. Clients MUST ignore any
       unknown capability values and proceed with the 'bundle-uri`
       dialog they support.

       The bundle-uri command is intended to be issued before fetch to
       get URIs to bundle files (see git-bundle(1)) to "seed" and inform
       the subsequent fetch command.

       The client CAN issue bundle-uri before or after any other valid
       command. To be useful to clients it’s expected that it’ll be
       issued after an ls-refs and before fetch, but CAN be issued at
       any time in the dialog.

       DISCUSSION of bundle-uri

           The intent of the feature is optimize for server resource
           consumption in the common case by changing the common case of
           fetching a very large PACK during git-clone(1) into a smaller
           incremental fetch.

           It also allows servers to achieve better caching in
           combination with an uploadpack.packObjectsHook (see
           git-config(1)).

           By having new clones or fetches be a more predictable and
           common negotiation against the tips of recently produces
           *.bundle file(s). Servers might even pre-generate the results
           of such negotiations for the uploadpack.packObjectsHook as
           new pushes come in.

           One way that servers could take advantage of these bundles is
           that the server would anticipate that fresh clones will
           download a known bundle, followed by catching up to the
           current state of the repository using ref tips found in that
           bundle (or bundles).

       PROTOCOL for bundle-uri

           A bundle-uri request takes no arguments, and as noted above
           does not currently advertise a capability value. Both may be
           added in the future.

           When the client issues a command=bundle-uri request, the
           response is a list of key-value pairs provided as packet
           lines with value <key>=<value>. Each <key> should be
           interpreted as a config key from the bundle.* namespace to
           construct a list of bundles. These keys are grouped by a
           bundle.<id>. subsection, where each key corresponding to a
           given <id> contributes attributes to the bundle defined by
           that <id>. See git-config(1) for the specific details of
           these keys and how the Git client will interpret their
           values.

           Clients MUST parse the line according to the above format,
           lines that do not conform to the format SHOULD be discarded.
           The user MAY be warned in such a case.

       bundle-uri CLIENT AND SERVER EXPECTATIONS

           URI CONTENTS
               The content at the advertised URIs MUST be one of two
               types.

               The advertised URI may contain a bundle file that git
               bundle verify would accept. I.e. they MUST contain one or
               more reference tips for use by the client, MUST indicate
               prerequisites (in any) with standard "-" prefixes, and
               MUST indicate their "object-format", if applicable.

               The advertised URI may alternatively contain a plaintext
               file that git config --list would accept (with the --file
               option). The key-value pairs in this list are in the
               bundle.*  namespace (see git-config(1)).

           bundle-uri CLIENT ERROR RECOVERY
               A client MUST above all gracefully degrade on errors,
               whether that error is because of bad missing/data in the
               bundle URI(s), because that client is too dumb to e.g.
               understand and fully parse out bundle headers and their
               prerequisite relationships, or something else.

               Server operators should feel confident in turning on
               "bundle-uri" and not worry if e.g. their CDN goes down
               that clones or fetches will run into hard failures. Even
               if the server bundle(s) are incomplete, or bad in some
               way the client should still end up with a functioning
               repository, just as if it had chosen not to use this
               protocol extension.

               All subsequent discussion on client and server
               interaction MUST keep this in mind.

           bundle-uri SERVER TO CLIENT
               The ordering of the returned bundle uris is not
               significant. Clients MUST parse their headers to discover
               their contained OIDS and prerequisites. A client MUST
               consider the content of the bundle(s) themselves and
               their header as the ultimate source of truth.

               A server MAY even return bundle(s) that don’t have any
               direct relationship to the repository being cloned
               (either through accident, or intentional "clever"
               configuration), and expect a client to sort out what data
               they’d like from the bundle(s), if any.

           bundle-uri CLIENT TO SERVER
               The client SHOULD provide reference tips found in the
               bundle header(s) as have lines in any subsequent fetch
               request. A client MAY also ignore the bundle(s) entirely
               if doing so is deemed worse for some reason, e.g. if the
               bundles can’t be downloaded, it doesn’t like the tips it
               finds etc.

           WHEN ADVERTISED BUNDLE(S) REQUIRE NO FURTHER NEGOTIATION
               If after issuing bundle-uri and ls-refs, and getting the
               header(s) of the bundle(s) the client finds that the ref
               tips it wants can be retrieved entirely from advertised
               bundle(s), the client MAY disconnect from the Git server.
               The results of such a clone or fetch should be
               indistinguishable from the state attained without using
               bundle-uri.

           EARLY CLIENT DISCONNECTIONS AND ERROR RECOVERY
               A client MAY perform an early disconnect while still
               downloading the bundle(s) (having streamed and parsed
               their headers). In such a case the client MUST gracefully
               recover from any errors related to finishing the download
               and validation of the bundle(s).

               I.e. a client might need to re-connect and issue a fetch
               command, and possibly fall back to not making use of
               bundle-uri at all.

               This "MAY" behavior is specified as such (and not a
               "SHOULD") on the assumption that a server advertising
               bundle uris is more likely than not to be serving up a
               relatively large repository, and to be pointing to URIs
               that have a good chance of being in working order. A
               client MAY e.g. look at the payload size of the bundles
               as a heuristic to see if an early disconnect is worth it,
               should falling back on a full "fetch" dialog be
               necessary.

           WHEN ADVERTISED BUNDLE(S) REQUIRE FURTHER NEGOTIATION
               A client SHOULD commence a negotiation of a PACK from the
               server via the "fetch" command using the OID tips found
               in advertised bundles, even if’s still in the process of
               downloading those bundle(s).

               This allows for aggressive early disconnects from any
               interactive server dialog. The client blindly trusts that
               the advertised OID tips are relevant, and issues them as
               have lines, it then requests any tips it would like
               (usually from the "ls-refs" advertisement) via want
               lines. The server will then compute a (hopefully small)
               PACK with the expected difference between the tips from
               the bundle(s) and the data requested.

               The only connection the client then needs to keep active
               is to the concurrently downloading static bundle(s), when
               those and the incremental PACK are retrieved they should
               be inflated and validated. Any errors at this point
               should be gracefully recovered from, see above.

       bundle-uri PROTOCOL FEATURES

           The client constructs a bundle list from the <key>=<value>
           pairs provided by the server. These pairs are part of the
           bundle.* namespace as documented in git-config(1). In this
           section, we discuss some of these keys and describe the
           actions the client will do in response to this information.

           In particular, the bundle.version key specifies an integer
           value. The only accepted value at the moment is 1, but if the
           client sees an unexpected value here then the client MUST
           ignore the bundle list.

           As long as bundle.version is understood, all other unknown
           keys MAY be ignored by the client. The server will guarantee
           compatibility with older clients, though newer clients may be
           better able to use the extra keys to minimize downloads.

           Any backwards-incompatible addition of pre-URI key-value will
           be guarded by a new bundle.version value or values in
           bundle-uri capability advertisement itself, and/or by new
           future bundle-uri request arguments.

           Some example key-value pairs that are not currently
           implemented but could be implemented in the future include:

           •   Add a "hash=<val>" or "size=<bytes>" advertise the
               expected hash or size of the bundle file.

           •   Advertise that one or more bundle files are the same (to
               e.g. have clients round-robin or otherwise choose one of
               N possible files).

           •   A "oid=<OID>" shortcut and "prerequisite=<OID>" shortcut.
               For expressing the common case of a bundle with one tip
               and no prerequisites, or one tip and one prerequisite.

               This would allow for optimizing the common case of
               servers who’d like to provide one "big bundle" containing
               only their "main" branch, and/or incremental updates
               thereof.

               A client receiving such a a response MAY assume that they
               can skip retrieving the header from a bundle at the
               indicated URI, and thus save themselves and the server(s)
               the request(s) needed to inspect the headers of that
               bundle or bundles.

GIT         top

       Part of the git(1) suite

NOTES         top

        1. api-trace2
           file:///home/mtk/share/doc/git-doc/technical/api-trace2.html

COLOPHON         top

       This page is part of the git (Git distributed version control
       system) project.  Information about the project can be found at
       ⟨http://git-scm.com/⟩.  If you have a bug report for this manual
       page, see ⟨http://git-scm.com/community⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨https://github.com/git/git.git⟩ on 2024-06-14.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2024-06-12.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       [email protected]

Git 2.45.2.492.gd63586         2024-06-12              GITPROTOCOL-V2(5)

Pages that refer to this page: git(1)git-config(1)git-upload-pack(1)gitformat-pack(5)gitprotocol-capabilities(5)gitprotocol-pack(5)