NAME

       gitformat-bundle - The bundle file format

SYNOPSIS

       *.bundle
       *.bdl

DESCRIPTION

       The Git bundle format is a format that represents both refs and Git objects. A bundle is a
       header in a format similar to git-show-ref(1) followed by a pack in *.pack format.

       The format is created and read by the git-bundle(1) command, and supported by e.g. git-
       fetch(1) and git-clone(1).

FORMAT

       We will use ABNF notation to define the Git bundle format. See gitprotocol-common(5) for
       the details.

       A v2 bundle looks like this:

           bundle    = signature *prerequisite *reference LF pack
           signature = "# v2 git bundle" LF

           prerequisite = "-" obj-id SP comment LF
           comment      = *CHAR
           reference    = obj-id SP refname LF

           pack         = ... ; packfile

       A v3 bundle looks like this:

           bundle    = signature *capability *prerequisite *reference LF pack
           signature = "# v3 git bundle" LF

           capability   = "@" key ["=" value] LF
           prerequisite = "-" obj-id SP comment LF
           comment      = *CHAR
           reference    = obj-id SP refname LF
           key          = 1*(ALPHA / DIGIT / "-")
           value        = *(%01-09 / %0b-FF)

           pack         = ... ; packfile

SEMANTICS

       A Git bundle consists of several parts.

       •   "Capabilities", which are only in the v3 format, indicate functionality that the
           bundle requires to be read properly.

       •   "Prerequisites" lists the objects that are NOT included in the bundle and the reader
           of the bundle MUST already have, in order to use the data in the bundle. The objects
           stored in the bundle may refer to prerequisite objects and anything reachable from
           them (e.g. a tree object in the bundle can reference a blob that is reachable from a
           prerequisite) and/or expressed as a delta against prerequisite objects.

       •   "References" record the tips of the history graph, iow, what the reader of the bundle
           CAN "git fetch" from it.

       •   "Pack" is the pack data stream "git fetch" would send, if you fetch from a repository
           that has the references recorded in the "References" above into a repository that has
           references pointing at the objects listed in "Prerequisites" above.

       In the bundle format, there can be a comment following a prerequisite obj-id. This is a
       comment and it has no specific meaning. The writer of the bundle MAY put any string here.
       The reader of the bundle MUST ignore the comment.

   Note on the shallow clone and a Git bundle
       Note that the prerequisites does not represent a shallow-clone boundary. The semantics of
       the prerequisites and the shallow-clone boundaries are different, and the Git bundle v2
       format cannot represent a shallow clone repository.

CAPABILITIES

       Because there is no opportunity for negotiation, unknown capabilities cause git bundle to
       abort.

       •   object-format specifies the hash algorithm in use, and can take the same values as the
           extensions.objectFormat configuration value.

       •   filter specifies an object filter as in the --filter option in git-rev-list(1). The
           resulting pack-file must be marked as a .promisor pack-file after it is unbundled.

GIT

       Part of the git(1) suite