The bundle format was not documented. Describe the format with ABNF and explain the meaning of each part. Signed-off-by: Masaya Suzuki <masayasuzuki@xxxxxxxxxx> --- Changes from v2: * Change "sender" and "receiver" to "writer" and "reader". * Add an example of a case that a bundle can reference an object outside of the bundle. * Mention that the prerequisites are different from the shallow boundary, and the bundle format cannot represent a shallow clone repository. Documentation/technical/bundle-format.txt | 48 +++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 Documentation/technical/bundle-format.txt diff --git a/Documentation/technical/bundle-format.txt b/Documentation/technical/bundle-format.txt new file mode 100644 index 0000000000..0e828151a5 --- /dev/null +++ b/Documentation/technical/bundle-format.txt @@ -0,0 +1,48 @@ += Git bundle v2 format + +The Git bundle format is a format that represents both refs and Git objects. + +== Format + +We will use ABNF notation to define the Git bundle format. See +protocol-common.txt for the details. + +---- +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 +---- + +== Semantics + +A Git bundle consists of three parts. + +* "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. -- 2.25.0.341.g760bfbb309-goog
