Git attributes support
Implement git attributes support for
- text attributes
- eol attributes
- macros
- binary macro
Large File Storage (LFS) Extension
Git Large File Storage (LFS) is a Git extension for versioning large files
LFS replaces large files such as audio samples, videos, datasets, and graphics with text pointers inside Git, while storing the file contents on a remote LFS server.
In 4.3 the following features to support LFS in JGit were implemented
- SHA-256 abstraction
- command line command debug-lfs-store to run LFS test server
- LFS server: support LFS protocol and a file system based LFS storage (used in Gerrit lfs-storage-fs plugin)
- LFS server: support Amazon S3 based storage for LFS (used in Gerrit lfs-storage-s3 plugin)
- fix FileLfsRepository to make it thread safe
RefTree
RefTree enables JGit to version refs (branches, tags and symbolic refs) in a Git tree and enables atomic push which is a precondition to implement Git Ketch.
A group of updates can be applied by updating the tree in one step, writing out a new root tree, and storing its SHA-1. If references are stored in RefTrees, comparing two repositories is a matter of checking if two SHA-1s are identical. Without RefTrees comparing two repositories requires listing all references and comparing the sets.
Track the "refs/" directory as a root tree by storing references that point directly at an object as a GITLINK entry in the tree. For example "refs/heads/master" is written as "heads/master".
Annotated tags also store their peeled value with ^{} suffix, using "tags/v1.0" and "tags/v1.0^{}" GITLINK entries.
Symbolic references are written as SYMLINK entries with the blob of the symlink carrying the name of the symbolic reference target.
HEAD is outside of "refs/" namespace so it is stored as a special "..HEAD" entry.
- debug-rebuild-ref-tree command line command to migrate refs to RefTreeDatabase
- copy HEAD into RefTree
- RefTreeDatabase: Allow ORIG_HEAD, etc. on non-bare repositories
- RefTreeDatabase: Expose bootstrap refs in getAdditionalRefs
Git Ketch
Git Ketch is a multi-master Git repository management system. Writes are successful only if a majority of participant servers agree. Acknowledged writes are durable against server failures as a majority of the participants store all required objects.
Git Ketch is modeled on the Raft Consensus Algorithm. A ketch sailing vessel is faster and more nimble than a raft. It can also carry more source codes. Git Ketch front-loads replication costs, which vaguely resembles a ketch sailing vessel's distinguishing feature of the main mast on the front of the ship.
In 4.3 the following Ketch features were implemented
- basic replication system
- simple map of running leader instances
- intercept push and route it through Ketch
- daemon: Add --ketch=LEADER flag
Repo command
- add ignoreRemoteFailures option to RepoCommand
- support revision in remote tag
Miscellaneous
- implement configuration option DIR_NO_GITLINKS
Build and Release Engineering
- Enable building JGit and Gerrit in the same Buck build to speed up build for features spanning JGit and Gerrit