NAME

got-worktree — Game of Trees work tree format

DESCRIPTION

A Got work tree stores a file hierarchy which corresponds to a versioned snapshot stored in a Git repository. The work tree's meta data is stored in the .got directory. A work tree is created with got checkout and is required to make changes to a Git repository with got(1).

A work tree stores the path to its Git repository, the name of a reference to the branch which files were checked out from, and the ID of a commit on this branch known as the base commit.

File meta-data is stored in a structured file called the file index which tracks the status of file modifications, additions, and deletions, relative to the base commit in the repository. The file index contains a series of records, and each such record contains the following status information for a particular file:

Copy of filesystem meta-data

Timestamp, file size, and file ownership information from stat(2). This is only used to detect file modifications and is never applied back to the filesystem. File permissions are not tracked, except for the executable bit. When versioned files are checked out into the work tree, the current umask(2) is heeded.

Blob object ID

The SHA1 hash of the blob object which corresponds to the contents of this file in the repository. The hash is stored as binary data.

Commit object ID

The SHA1 hash of the commit object the file was checked out from. The hash is stored as binary data. This data is used to detect past incomplete update operations. Entries which do not match the work tree's base commit may still need to be updated to match file content stored in the base commit.

Flags

This field contains the length, according to strlen(3), of path data which follows, and the following flags:

STAGE

Reflects the added, modified, or deleted staged state of a path staged with got stage.

NOT_FLUSHED

The entry was added to the file index in memory and does not exist in file index data read from disk. This happens to files which are added to the work tree while operations such as got checkout, got update, got cherrypick, got backout, got rebase, and got histedit are in progress. This flag is always cleared before the entry is written to disk.

NO_BLOB

The entry's on-disk file content in the work tree is not based on a blob in the repository. The blob object ID of this entry must be considered invalid. This happens when unversioned files are added with got add and when files are added to the work tree by operations such as got cherrypick, got backout, got rebase, and got histedit.

NO_COMMIT

The entry is not based on a commit in the repository. The commit object ID of this entry must be considered invalid. This happens when unversioned files are added with got add and when files are added to the work tree by operations such as got cherrypick, got backout, got rebase, and got histedit.

NO_FILE_ON_DISK

The entry has no corresponding on-disk file in the work tree. This happens when files are removed with got remove.

Path data

The path of the entry, relative to the work tree root. Path data is of variable length and NUL-padded to a multiple of 8 bytes.

Staged blob object ID

The SHA1 hash of a blob object containing file content which has been staged for commit. The hash is stored as binary data. Only present if a file addition or modification has been staged with got stage.

A corrupt or missing file index can be recreated on demand as follows:

When the file index is modified, it is read into memory in its entirety, modified in place, and written to a temporary file. This temporary file is then moved on top of the old file index with rename(2). This ensures that no other processes see an inconsistent file index which is in the process of being written.

Work tree meta data must only be modified while the work tree's lock file has been exclusively locked with lockf(3).

Each work tree has a universal unique identifier. When a work tree is checked out or updated, this identifier is used to create a reference to the current base commit in the Git repository. The presence of this reference prevents the Git garbage collector and gotadmin cleanup from discarding the base commit and any objects it refers to. When a work tree is no longer needed, its reference can be deleted from the Git repository with got ref -d.

FILES

.got

Meta-data directory where all files listed below reside.

base-commit

SHA1 hex-string representation of the current base commit.

file-index

File status information.

format

Work tree format number.

got.conf

Configuration file for got(1). See got.conf(5).

head-ref

Name of the reference to the current branch.

lock

Lock file to obtain exclusive write access to meta data.

path-prefix

Path inside repository the work tree was checked out from.

repository

Path to the repository the work tree was checked out from.

uuid

A universal unique identifier for the work tree.

SEE ALSO

got(1), rename(2), stat(2), umask(2), lockf(3), git-repository(5), got.conf(5)