GITFORMAT-BUNDLE(5) Git Manual GITFORMAT-BUNDLE(5)

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.

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

+o "Prerequisites" list 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.

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

+o "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 shallow clones and Git bundles

Note that the prerequisites do 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.

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

+o 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

Git 2.48.1 2025-01-13 GITFORMAT-BUNDLE(5)