When opening a worktree via the gitdir of its parent repository
we fail to correctly set up the worktree's working directory. The
problem here is two-fold: we first fail to see that the gitdir
actually is a gitdir of a working tree and then subsequently
fail to determine the working tree location from the gitdir.
The first problem of not noticing a gitdir belongs to a worktree
can be solved by checking for the existence of a `gitdir` file in
the gitdir. This file points back to the gitlink file located in
the working tree's working directory. As this file only exists
for worktrees, it should be sufficient indication of the gitdir
belonging to a worktree.
The second problem, that is determining the location of the
worktree's working directory, can then be solved by reading the
`gitdir` file in the working directory's gitdir. When we now
resolve relative paths and strip the final `.git` component, we
have the actual worktree's working directory location.
The `path_repository` variable is actually confusing to think
about, as it is not always clear what the repository actually is.
It may either be the path to the folder containing worktree and
.git directory, the path to .git itself, a worktree or something
entirely different. Actually, the intent of the variable is to
hold the path to the gitdir, which is either the .git directory
or the bare repository.
Rename the variable to `gitdir` to avoid confusion. While at it,
also rename `path_gitlink` to `gitlink` to improve consistency.
If a branch is already checked out in a working tree we are not
allowed to check out that branch in another repository. Introduce
this restriction when setting a repository's HEAD.
Implement a new function that is able to determine if a branch is
checked out in any repository connected to the current
repository. In particular, this is required to check if for a
given repository and branch, there exists any working tree
connected to that repository that is referencing this branch.
Implement `git_repository_head_for_worktree` and
`git_repository_head_detached_for_worktree` for directly accessing a
worktree's HEAD without opening it as a `git_repository` first.
Implement the `git_worktree_prune` function. This function can be
used to delete working trees from a repository. According to the
flags passed to it, it can either delete the working tree's
gitdir only or both gitdir and the working directory.
Working trees support locking by creating a file `locked` inside
the tree's gitdir with an optional reason inside. Support this
feature by adding functions to get and set the locking status.
Add a new function that checks wether a given `struct
git_worktree` is valid. The validation includes checking if the
gitdir, parent directory and common directory are present.
Introduce a new `struct git_worktree`, which holds information
about a possible working tree connected to a repository.
Introduce functions to allow opening working trees for a
repository.
A repository's configuartion file can always be found in the
GIT_COMMON_DIR, which has been newly introduced. For normal
repositories this does change nothing, but for working trees this
change allows to access the shared configuration file.
The refdb_fs_backend is not aware of the git commondir, which
stores common objects like the o bject database and packed/loose
refereensces when worktrees are used.
Make refdb_fs_backend aware of the common directory by
introducing a new commonpath variable that points to the actual
common path of the database and using it instead of the gitdir
for the mentioned objects.
The variable '.path' of the refdb_fs_backend struct becomes
confusing regarding the introduction of the git commondir. It
does not immediatly become obvious what it should point to.
Fix this problem by renaming the variable to `gitpath`,
clarifying that it acutally points to the `.git` directory of the
repository, in contrast to the commonpath directory, which points
to the directory containing shared objects like references and
the object store.
The recent introduction of the commondir variable of a repository
requires callers to distinguish whether their files are part of
the dot-git directory or the common directory shared between
multpile worktrees. In order to take the burden from callers and
unify knowledge on which files reside where, the
`git_repository_item_path` function has been introduced which
encapsulate this knowledge.
Modify most existing callers of `git_repository_path` to use
`git_repository_item_path` instead, thus making them implicitly
aware of the common directory.
The commondir variable stores the path to the common directory.
The common directory is used to store objects and references
shared across multiple repositories. A current use case is the
newly introduced `git worktree` feature, which sets up a separate
working copy, where the backing git object store and references
are pointed to by the common directory.
Create worktrees for submodule repositories. The worktrees are
created for the parent repository (e.g. the one containing
submodules) and for the contained child repository.
As of recently, we failed to correctly discover repositories at a
Win32 system root. Instead of aborting the upwards-traversal of
the file system, we were looping infinitely when traversal
started at either a Win32 drive prefix ("C:/") or a network path
("//somehost").
The issue has been fixed, so add a test to catch regressions.
When calling `git_path_dirname_r` on a Win32 prefix, e.g. a drive
or network share prefix, we always want to return the trailing
'/'. This does not work currently when passing in a path like
'C:', where the '/' would not be appended correctly.
Fix this by appending a '/' if we try to normalize a Win32 prefix
and there is no trailing '/'.
Getting the dirname of a filesystem root should return the filesystem
root itself. E.g. the dirname of "/" is always "/". On Windows, we
emulate this behavior and as such, we should return e.g. "C:/" if
calling dirname on "C:/". But we currently fail to do so and instead
return ".", as we do not check if we actually have a Windows prefix
before stripping off the last directory component.
Fix this by calling out to `win32_prefix_length` immediately after
stripping trailing slashes, returning early if we have a prefix.
Extract code which determines if a path is at a Windows system's root.
This incluses drive prefixes (e.g. "C:\") as well as network computer
names (e.g. "//computername/").
