Commit c7b3a3d2 authored by Duy Nguyen's avatar Duy Nguyen Committed by Junio C Hamano

$GIT_COMMON_DIR: a new environment variable

This variable is intended to support multiple working directories
attached to a repository. Such a repository may have a main working
directory, created by either "git init" or "git clone" and one or more
linked working directories. These working directories and the main
repository share the same repository directory.

In linked working directories, $GIT_COMMON_DIR must be defined to point
to the real repository directory and $GIT_DIR points to an unused
subdirectory inside $GIT_COMMON_DIR. File locations inside the
repository are reorganized from the linked worktree view point:

 - worktree-specific such as HEAD, logs/HEAD, index, other top-level
   refs and unrecognized files are from $GIT_DIR.

 - the rest like objects, refs, info, hooks, packed-refs, shallow...
   are from $GIT_COMMON_DIR (except info/sparse-checkout, but that's
   a separate patch)

Scripts are supposed to retrieve paths in $GIT_DIR with "git rev-parse
--git-path", which will take care of "$GIT_DIR vs $GIT_COMMON_DIR"
business.

The redirection is done by git_path(), git_pathdup() and
strbuf_git_path(). The selected list of paths goes to $GIT_COMMON_DIR,
not the other way around in case a developer adds a new
worktree-specific file and it's accidentally promoted to be shared
across repositories (this includes unknown files added by third party
commands)

The list of known files that belong to $GIT_DIR are:

ADD_EDIT.patch BISECT_ANCESTORS_OK BISECT_EXPECTED_REV BISECT_LOG
BISECT_NAMES CHERRY_PICK_HEAD COMMIT_MSG FETCH_HEAD HEAD MERGE_HEAD
MERGE_MODE MERGE_RR NOTES_EDITMSG NOTES_MERGE_WORKTREE ORIG_HEAD
REVERT_HEAD SQUASH_MSG TAG_EDITMSG fast_import_crash_* logs/HEAD
next-index-* rebase-apply rebase-merge rsync-refs-* sequencer/*
shallow_*

Path mapping is NOT done for git_path_submodule(). Multi-checkouts are
not supported as submodules.
Helped-by: default avatarJens Lehmann <[email protected]>
Signed-off-by: Duy Nguyen's avatarNguyễn Thái Ngọc Duy <[email protected]>
Signed-off-by: default avatarJunio C Hamano <[email protected]>
parent af07b20d
......@@ -809,6 +809,14 @@ Git so take care if using Cogito etc.
an explicit repository directory set via 'GIT_DIR' or on the
command line.
'GIT_COMMON_DIR'::
If this variable is set to a path, non-worktree files that are
normally in $GIT_DIR will be taken from this path
instead. Worktree-specific files such as HEAD or index are
taken from $GIT_DIR. See linkgit:gitrepository-layout[5] for
details. This variable has lower precedence than other path
variables such as GIT_INDEX_FILE, GIT_OBJECT_DIRECTORY...
Git Commits
~~~~~~~~~~~
'GIT_AUTHOR_NAME'::
......
......@@ -46,6 +46,9 @@ of incomplete object store is not suitable to be published for
use with dumb transports but otherwise is OK as long as
`objects/info/alternates` points at the object stores it
borrows from.
+
This directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/objects" will be used instead.
objects/[0-9a-f][0-9a-f]::
A newly created object is stored in its own file.
......@@ -92,7 +95,8 @@ refs::
References are stored in subdirectories of this
directory. The 'git prune' command knows to preserve
objects reachable from refs found in this directory and
its subdirectories.
its subdirectories. This directory is ignored if $GIT_COMMON_DIR
is set and "$GIT_COMMON_DIR/refs" will be used instead.
refs/heads/`name`::
records tip-of-the-tree commit objects of branch `name`
......@@ -114,7 +118,8 @@ refs/replace/`<obj-sha1>`::
packed-refs::
records the same information as refs/heads/, refs/tags/,
and friends record in a more efficient way. See
linkgit:git-pack-refs[1].
linkgit:git-pack-refs[1]. This file is ignored if $GIT_COMMON_DIR
is set and "$GIT_COMMON_DIR/packed-refs" will be used instead.
HEAD::
A symref (see glossary) to the `refs/heads/` namespace
......@@ -133,6 +138,11 @@ being a symref to point at the current branch. Such a state
is often called 'detached HEAD.' See linkgit:git-checkout[1]
for details.
config::
Repository specific configuration file. This file is ignored
if $GIT_COMMON_DIR is set and "$GIT_COMMON_DIR/config" will be
used instead.
branches::
A slightly deprecated way to store shorthands to be used
to specify a URL to 'git fetch', 'git pull' and 'git push'.
......@@ -140,7 +150,10 @@ branches::
'name' can be given to these commands in place of
'repository' argument. See the REMOTES section in
linkgit:git-fetch[1] for details. This mechanism is legacy
and not likely to be found in modern repositories.
and not likely to be found in modern repositories. This
directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/branches" will be used instead.
hooks::
Hooks are customization scripts used by various Git
......@@ -149,7 +162,9 @@ hooks::
default. To enable, the `.sample` suffix has to be
removed from the filename by renaming.
Read linkgit:githooks[5] for more details about
each hook.
each hook. This directory is ignored if $GIT_COMMON_DIR is set
and "$GIT_COMMON_DIR/hooks" will be used instead.
index::
The current index file for the repository. It is
......@@ -161,7 +176,8 @@ sharedindex.<SHA-1>::
info::
Additional information about the repository is recorded
in this directory.
in this directory. This directory is ignored if $GIT_COMMON_DIR
is set and "$GIT_COMMON_DIR/index" will be used instead.
info/refs::
This file helps dumb transports discover what refs are
......@@ -201,12 +217,15 @@ remotes::
when interacting with remote repositories via 'git fetch',
'git pull' and 'git push' commands. See the REMOTES section
in linkgit:git-fetch[1] for details. This mechanism is legacy
and not likely to be found in modern repositories.
and not likely to be found in modern repositories. This
directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/remotes" will be used instead.
logs::
Records of changes made to refs are stored in this
directory. See linkgit:git-update-ref[1]
for more information.
Records of changes made to refs are stored in this directory.
See linkgit:git-update-ref[1] for more information. This
directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/logs" will be used instead.
logs/refs/heads/`name`::
Records all changes made to the branch tip named `name`.
......@@ -217,10 +236,14 @@ logs/refs/tags/`name`::
shallow::
This is similar to `info/grafts` but is internally used
and maintained by shallow clone mechanism. See `--depth`
option to linkgit:git-clone[1] and linkgit:git-fetch[1].
option to linkgit:git-clone[1] and linkgit:git-fetch[1]. This
file is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/shallow" will be used instead.
modules::
Contains the git-repositories of the submodules.
Contains the git-repositories of the submodules. This
directory is ignored if $GIT_COMMON_DIR is set and
"$GIT_COMMON_DIR/modules" will be used instead.
SEE ALSO
--------
......
......@@ -377,6 +377,7 @@ static inline enum object_type object_type(unsigned int mode)
/* Double-check local_repo_env below if you add to this list. */
#define GIT_DIR_ENVIRONMENT "GIT_DIR"
#define GIT_COMMON_DIR_ENVIRONMENT "GIT_COMMON_DIR"
#define GIT_NAMESPACE_ENVIRONMENT "GIT_NAMESPACE"
#define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"
#define GIT_PREFIX_ENVIRONMENT "GIT_PREFIX"
......@@ -430,6 +431,7 @@ extern int is_inside_git_dir(void);
extern char *git_work_tree_cfg;
extern int is_inside_work_tree(void);
extern const char *get_git_dir(void);
extern const char *get_git_common_dir(void);
extern int is_git_directory(const char *path);
extern char *get_object_directory(void);
extern char *get_index_file(void);
......@@ -617,7 +619,7 @@ extern int fsync_object_files;
extern int core_preload_index;
extern int core_apply_sparse_checkout;
extern int precomposed_unicode;
extern int git_db_env, git_index_env, git_graft_env;
extern int git_db_env, git_index_env, git_graft_env, git_common_dir_env;
/*
* The character that begins a commented line in user-editable file
......
......@@ -81,9 +81,9 @@ static char *work_tree;
static const char *namespace;
static size_t namespace_len;
static const char *git_dir;
static const char *git_dir, *git_common_dir;
static char *git_object_dir, *git_index_file, *git_graft_file;
int git_db_env, git_index_env, git_graft_env;
int git_db_env, git_index_env, git_graft_env, git_common_dir_env;
/*
* Repository-local GIT_* environment variables; see cache.h for details.
......@@ -101,6 +101,7 @@ const char * const local_repo_env[] = {
NO_REPLACE_OBJECTS_ENVIRONMENT,
GIT_PREFIX_ENVIRONMENT,
GIT_SHALLOW_FILE_ENVIRONMENT,
GIT_COMMON_DIR_ENVIRONMENT,
NULL
};
......@@ -125,8 +126,8 @@ static char *expand_namespace(const char *raw_namespace)
return strbuf_detach(&buf, NULL);
}
static char *git_path_from_env(const char *envvar, const char *path,
int *fromenv)
static char *git_path_from_env(const char *envvar, const char *git_dir,
const char *path, int *fromenv)
{
const char *value = getenv(envvar);
if (!value) {
......@@ -149,9 +150,18 @@ static void setup_git_env(void)
git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
gitfile = read_gitfile(git_dir);
git_dir = xstrdup(gitfile ? gitfile : git_dir);
git_object_dir = git_path_from_env(DB_ENVIRONMENT, "objects", &git_db_env);
git_index_file = git_path_from_env(INDEX_ENVIRONMENT, "index", &git_index_env);
git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, "info/grafts", &git_graft_env);
git_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
if (git_common_dir) {
git_common_dir_env = 1;
git_common_dir = xstrdup(git_common_dir);
} else
git_common_dir = git_dir;
git_object_dir = git_path_from_env(DB_ENVIRONMENT, git_common_dir,
"objects", &git_db_env);
git_index_file = git_path_from_env(INDEX_ENVIRONMENT, git_dir,
"index", &git_index_env);
git_graft_file = git_path_from_env(GRAFT_ENVIRONMENT, git_common_dir,
"info/grafts", &git_graft_env);
if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
check_replace_refs = 0;
namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
......@@ -174,6 +184,11 @@ const char *get_git_dir(void)
return git_dir;
}
const char *get_git_common_dir(void)
{
return git_common_dir;
}
const char *get_git_namespace(void)
{
if (!namespace)
......
......@@ -90,6 +90,38 @@ static void replace_dir(struct strbuf *buf, int len, const char *newdir)
buf->buf[newlen] = '/';
}
static const char *common_list[] = {
"/branches", "/hooks", "/info", "/logs", "/lost-found", "/modules",
"/objects", "/refs", "/remotes", "/rr-cache", "/svn",
"config", "gc.pid", "packed-refs", "shallow",
NULL
};
static void update_common_dir(struct strbuf *buf, int git_dir_len)
{
char *base = buf->buf + git_dir_len;
const char **p;
if (is_dir_file(base, "logs", "HEAD"))
return; /* keep this in $GIT_DIR */
for (p = common_list; *p; p++) {
const char *path = *p;
int is_dir = 0;
if (*path == '/') {
path++;
is_dir = 1;
}
if (is_dir && dir_prefix(base, path)) {
replace_dir(buf, git_dir_len, get_git_common_dir());
return;
}
if (!is_dir && !strcmp(base, path)) {
replace_dir(buf, git_dir_len, get_git_common_dir());
return;
}
}
}
static void adjust_git_path(struct strbuf *buf, int git_dir_len)
{
const char *base = buf->buf + git_dir_len;
......@@ -101,6 +133,8 @@ static void adjust_git_path(struct strbuf *buf, int git_dir_len)
get_index_file(), strlen(get_index_file()));
else if (git_db_env && dir_prefix(base, "objects"))
replace_dir(buf, git_dir_len + 7, get_object_directory());
else if (git_common_dir_env)
update_common_dir(buf, git_dir_len);
}
static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
......
......@@ -262,5 +262,21 @@ test_expect_success 'setup fake objects directory foo' 'mkdir foo'
test_git_path GIT_OBJECT_DIRECTORY=foo objects foo
test_git_path GIT_OBJECT_DIRECTORY=foo objects/foo foo/foo
test_git_path GIT_OBJECT_DIRECTORY=foo objects2 .git/objects2
test_expect_success 'setup common repository' 'git --git-dir=bar init'
test_git_path GIT_COMMON_DIR=bar index .git/index
test_git_path GIT_COMMON_DIR=bar HEAD .git/HEAD
test_git_path GIT_COMMON_DIR=bar logs/HEAD .git/logs/HEAD
test_git_path GIT_COMMON_DIR=bar objects bar/objects
test_git_path GIT_COMMON_DIR=bar objects/bar bar/objects/bar
test_git_path GIT_COMMON_DIR=bar info/exclude bar/info/exclude
test_git_path GIT_COMMON_DIR=bar info/grafts bar/info/grafts
test_git_path GIT_COMMON_DIR=bar remotes/bar bar/remotes/bar
test_git_path GIT_COMMON_DIR=bar branches/bar bar/branches/bar
test_git_path GIT_COMMON_DIR=bar logs/refs/heads/master bar/logs/refs/heads/master
test_git_path GIT_COMMON_DIR=bar refs/heads/master bar/refs/heads/master
test_git_path GIT_COMMON_DIR=bar hooks/me bar/hooks/me
test_git_path GIT_COMMON_DIR=bar config bar/config
test_git_path GIT_COMMON_DIR=bar packed-refs bar/packed-refs
test_git_path GIT_COMMON_DIR=bar shallow bar/shallow
test_done
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