diff mbox series

[v3,3/5] worktree: optionally link worktrees with relative paths

Message ID 20241025-wt_relative_paths-v3-3-8860a5321c01@pm.me (mailing list archive)
State New
Headers show
Series Optionally link worktrees with relative paths | expand

Commit Message

Caleb White Oct. 25, 2024, 8:57 p.m. UTC
Git stores absolute paths when linking worktrees to the main repository.
However, this can cause problems when moving repositories and worktrees,
or when working in containerized environments where absolute paths
differ between systems. The worktree links break, and users are required
to manually execute `worktree repair` to repair them, leading to workflow
disruptions. Additionally, when repositories are mapped inside containers
with different absolute paths, they may become unusable. Repairing
worktrees in the container can then break them outside the container.

In some cases, relative paths can eliminate the need for `worktree repair`.
If both the repository and worktrees are moved together while preserving
their relative locations, the links remain intact. Common examples include
moving repositories and worktrees or mapping both inside containers that
use different absolute paths.

This patch adds support for optionally _writing_ relative paths to the
linking files. If desired, relative paths can be created through the
`--relative-paths` CLI option for `worktree {add,move,repair}` as well
as the `worktree.useRelativePaths` config option. If an existing
worktree uses absolute paths, executing `worktree {move,repair}` with
the relative option will create relative paths (and visa versa).

A new function, `write_worktree_linking_files()` is introduced to clean
the actual relative path computation in different locations. The
function accepts a strbuf to the worktree `.git` file and a strbuf to
the repository `gitdir` file and then writes the appropriate path to
each as configured by the user.

Additionally, `repair_worktrees_after_gitdir_move()` has been introduced
to address the case where both the `<worktree>/.git` and
`<repo>/worktrees/<id>/gitdir` links are broken after the gitdir is
moved (such as during a re-initialization). This function repairs both
sides of the worktree link using the old gitdir path to reestablish the
correct paths after a move.

Signed-off-by: Caleb White <cdwhite3@pm.me>
---
 Documentation/config/worktree.txt |   5 ++
 Documentation/git-worktree.txt    |   9 +++
 builtin/worktree.c                |  18 +++---
 setup.c                           |   2 +-
 t/t0001-init.sh                   |  20 +++++--
 t/t2400-worktree-add.sh           |  41 ++++++++++++++
 t/t2402-worktree-list.sh          |  22 ++++++++
 t/t2403-worktree-move.sh          |  22 ++++++++
 t/t2406-worktree-repair.sh        |  26 +++++++++
 worktree.c                        | 116 +++++++++++++++++++++++++++++++-------
 worktree.h                        |  24 ++++++++
 11 files changed, 270 insertions(+), 35 deletions(-)
diff mbox series

Patch

diff --git a/Documentation/config/worktree.txt b/Documentation/config/worktree.txt
index 048e349482df6c892055720eb53cdcd6c327b6ed..d0589c21d034f07f70ca172947520d7d78720cca 100644
--- a/Documentation/config/worktree.txt
+++ b/Documentation/config/worktree.txt
@@ -7,3 +7,8 @@  worktree.guessRemote::
 	such a branch exists, it is checked out and set as "upstream"
 	for the new branch.  If no such match can be found, it falls
 	back to creating a new branch from the current HEAD.
+worktree.useRelativePaths::
+	If set to `true`, the worktree paths will be stored relative to the
+	repository’s top-level directory, rather than using absolute paths.
+	This is particularly useful for setups where the repository may be moved
+	between different locations or environments.
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 70437c815f13852bd2eb862176b8b933e6de0acf..4a6ad481ee1d44b43683bd67881a2771e2b090c7 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -216,6 +216,15 @@  To remove a locked worktree, specify `--force` twice.
 This can also be set up as the default behaviour by using the
 `worktree.guessRemote` config option.
 
+--[no-]relative-paths::
+	The worktree paths will be stored relative to the repository’s
+	top-level directory, rather than using absolute paths.
+	This is particularly useful for setups where the repository may be moved
+	between different locations or environments.
++
+This can also be set up as the default behaviour by using the
+`worktree.useRelativePaths` config option.
+
 --[no-]track::
 	When creating a new branch, if `<commit-ish>` is a branch,
 	mark it as "upstream" from the new branch.  This is the
diff --git a/builtin/worktree.c b/builtin/worktree.c
index fc31d072a620d7b455d7f150bd3a9e773ee9d4ed..bb06830d6fe82aa97833c6e87f034115dfaa23bd 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -134,6 +134,9 @@  static int git_worktree_config(const char *var, const char *value,
 	if (!strcmp(var, "worktree.guessremote")) {
 		guess_remote = git_config_bool(var, value);
 		return 0;
+	} else if (!strcmp(var, "worktree.userelativepaths")) {
+		use_relative_paths = git_config_bool(var, value);
+		return 0;
 	}
 
 	return git_default_config(var, value, ctx, cb);
@@ -414,7 +417,7 @@  static int add_worktree(const char *path, const char *refname,
 			const struct add_opts *opts)
 {
 	struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
-	struct strbuf sb = STRBUF_INIT, realpath = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 	const char *name;
 	struct strvec child_env = STRVEC_INIT;
 	unsigned int counter = 0;
@@ -490,11 +493,7 @@  static int add_worktree(const char *path, const char *refname,
 
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
-	strbuf_realpath(&realpath, sb_git.buf, 1);
-	write_file(sb.buf, "%s", realpath.buf);
-	strbuf_realpath(&realpath, repo_get_common_dir(the_repository), 1);
-	write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
-		   realpath.buf, name);
+	write_worktree_linking_files(sb_git, sb);
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
@@ -582,7 +581,6 @@  static int add_worktree(const char *path, const char *refname,
 	strbuf_release(&sb_repo);
 	strbuf_release(&sb_git);
 	strbuf_release(&sb_name);
-	strbuf_release(&realpath);
 	free_worktree(wt);
 	return ret;
 }
@@ -794,6 +792,8 @@  static int add(int ac, const char **av, const char *prefix)
 			     PARSE_OPT_NOARG | PARSE_OPT_OPTARG),
 		OPT_BOOL(0, "guess-remote", &guess_remote,
 			 N_("try to match the new branch name with a remote-tracking branch")),
+		OPT_BOOL(0, "relative-paths", &use_relative_paths,
+			 N_("use relative paths for worktrees")),
 		OPT_END()
 	};
 	int ret;
@@ -1187,6 +1187,8 @@  static int move_worktree(int ac, const char **av, const char *prefix)
 		OPT__FORCE(&force,
 			 N_("force move even if worktree is dirty or locked"),
 			 PARSE_OPT_NOCOMPLETE),
+		OPT_BOOL(0, "relative-paths", &use_relative_paths,
+			 N_("use relative paths for worktrees")),
 		OPT_END()
 	};
 	struct worktree **worktrees, *wt;
@@ -1380,6 +1382,8 @@  static int repair(int ac, const char **av, const char *prefix)
 	const char **p;
 	const char *self[] = { ".", NULL };
 	struct option options[] = {
+		OPT_BOOL(0, "relative-paths", &use_relative_paths,
+			 N_("use relative paths for worktrees")),
 		OPT_END()
 	};
 	int rc = 0;
diff --git a/setup.c b/setup.c
index 94e79b2e487f3faa537547e190acf9b7ea0be3b5..7b648de0279116b381eea46800ad130606926103 100644
--- a/setup.c
+++ b/setup.c
@@ -2420,7 +2420,7 @@  static void separate_git_dir(const char *git_dir, const char *git_link)
 
 		if (rename(src, git_dir))
 			die_errno(_("unable to move %s to %s"), src, git_dir);
-		repair_worktrees(NULL, NULL);
+		repair_worktrees_after_gitdir_move(src);
 	}
 
 	write_file(git_link, "gitdir: %s", git_dir);
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 0178aa62a41f1606f2382a4a10ab593ccf11e0e8..03ac9624cb418d05adb8dfb786c31b809c73efec 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -435,19 +435,27 @@  sep_git_dir_worktree ()  {
 	test_when_finished "rm -rf mainwt linkwt seprepo" &&
 	git init mainwt &&
 	test_commit -C mainwt gumby &&
-	git -C mainwt worktree add --detach ../linkwt &&
-	git -C "$1" init --separate-git-dir ../seprepo &&
+	git -C mainwt worktree add $1 --detach ../linkwt &&
+	git -C "$2" init --separate-git-dir ../seprepo &&
 	git -C mainwt rev-parse --git-common-dir >expect &&
 	git -C linkwt rev-parse --git-common-dir >actual &&
 	test_cmp expect actual
 }
 
-test_expect_success 're-init to move gitdir with linked worktrees' '
-	sep_git_dir_worktree mainwt
+test_expect_success 're-init to move gitdir with linked worktrees (absolute)' '
+	sep_git_dir_worktree --no-relative-paths mainwt
 '
 
-test_expect_success 're-init to move gitdir within linked worktree' '
-	sep_git_dir_worktree linkwt
+test_expect_success 're-init to move gitdir within linked worktree (absolute)' '
+	sep_git_dir_worktree --no-relative-paths linkwt
+'
+
+test_expect_success 're-init to move gitdir with linked worktrees (relative)' '
+	sep_git_dir_worktree --relative-paths mainwt
+'
+
+test_expect_success 're-init to move gitdir within linked worktree (relative)' '
+	sep_git_dir_worktree --relative-paths linkwt
 '
 
 test_expect_success MINGW '.git hidden' '
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index cfc4aeb1798c6d023909cec771e5b74e983af5ea..630c13230b3cc762ce8d943e22be8891aa2b1871 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -1207,4 +1207,45 @@  test_expect_success '"add" with initialized submodule, with submodule.recurse se
 	git -C project-clone -c submodule.recurse worktree add ../project-5
 '
 
+test_expect_success 'can create worktrees with relative paths' '
+	test_when_finished "git worktree remove relative" &&
+	git config worktree.useRelativePaths false &&
+	git worktree add --relative-paths ./relative &&
+	cat relative/.git >actual &&
+	echo "gitdir: ../.git/worktrees/relative" >expect &&
+	test_cmp expect actual &&
+	cat .git/worktrees/relative/gitdir >actual &&
+	echo "../../../relative/.git" >expect &&
+	test_cmp expect actual
+
+'
+
+test_expect_success 'can create worktrees with absolute paths' '
+	git config worktree.useRelativePaths true &&
+	git worktree add ./relative &&
+	cat relative/.git >actual &&
+	echo "gitdir: ../.git/worktrees/relative" >expect &&
+	test_cmp expect actual &&
+	git worktree add --no-relative-paths ./absolute &&
+	cat absolute/.git >actual &&
+	echo "gitdir: $(pwd)/.git/worktrees/absolute" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'move repo without breaking relative internal links' '
+	test_when_finished rm -rf repo moved &&
+	git init repo &&
+	(
+		cd repo &&
+		git config worktree.useRelativePaths true &&
+		test_commit initial &&
+		git worktree add wt1 &&
+		cd .. &&
+		mv repo moved &&
+		cd moved/wt1 &&
+		git status >out 2>err &&
+		test_must_be_empty err
+	)
+'
+
 test_done
diff --git a/t/t2402-worktree-list.sh b/t/t2402-worktree-list.sh
index 33ea9cb21ba07c9563530b54da06753eaa993fe2..780daa6cd6351f8fa9434619cc212aade8f01420 100755
--- a/t/t2402-worktree-list.sh
+++ b/t/t2402-worktree-list.sh
@@ -261,6 +261,7 @@  test_expect_success 'broken main worktree still at the top' '
 '
 
 test_expect_success 'linked worktrees are sorted' '
+	test_when_finished "rm -rf sorted" &&
 	mkdir sorted &&
 	git init sorted/main &&
 	(
@@ -280,6 +281,27 @@  test_expect_success 'linked worktrees are sorted' '
 	test_cmp expected sorted/main/actual
 '
 
+test_expect_success 'linked worktrees with relative paths are shown with absolute paths' '
+	test_when_finished "rm -rf sorted" &&
+	mkdir sorted &&
+	git init sorted/main &&
+	(
+		cd sorted/main &&
+		test_tick &&
+		test_commit new &&
+		git worktree add --relative-paths ../first &&
+		git worktree add ../second &&
+		git worktree list --porcelain >out &&
+		grep ^worktree out >actual
+	) &&
+	cat >expected <<-EOF &&
+	worktree $(pwd)/sorted/main
+	worktree $(pwd)/sorted/first
+	worktree $(pwd)/sorted/second
+	EOF
+	test_cmp expected sorted/main/actual
+'
+
 test_expect_success 'worktree path when called in .git directory' '
 	git worktree list >list1 &&
 	git -C .git worktree list >list2 &&
diff --git a/t/t2403-worktree-move.sh b/t/t2403-worktree-move.sh
index 901342ea09b51a8e832f1109fbb737df84283aa2..6ce9ed3f1e6b3f73d2a290e770233eec30221fe5 100755
--- a/t/t2403-worktree-move.sh
+++ b/t/t2403-worktree-move.sh
@@ -247,4 +247,26 @@  test_expect_success 'not remove a repo with initialized submodule' '
 	)
 '
 
+test_expect_success 'move worktree with absolute path to relative path' '
+	git config worktree.useRelativePaths false &&
+	git worktree add ./absolute &&
+	git worktree move --relative-paths absolute relative &&
+	cat relative/.git >actual &&
+	echo "gitdir: ../.git/worktrees/absolute" >expect &&
+	test_cmp expect actual &&
+	git config worktree.useRelativePaths true &&
+	git worktree move relative relative2 &&
+	cat relative2/.git >actual &&
+	echo "gitdir: ../.git/worktrees/absolute" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'move worktree with relative path to absolute path' '
+	git config worktree.useRelativePaths true &&
+	git worktree move --no-relative-paths relative2 absolute &&
+	cat absolute/.git >actual &&
+	echo "gitdir: $(pwd)/.git/worktrees/absolute" >expect &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t2406-worktree-repair.sh b/t/t2406-worktree-repair.sh
index 7686e60f6ad186519b275f11a5e14064c905b207..84451e903b2ef3c645c0311faf055c846588baf6 100755
--- a/t/t2406-worktree-repair.sh
+++ b/t/t2406-worktree-repair.sh
@@ -216,4 +216,30 @@  test_expect_success 'repair copied main and linked worktrees' '
 	test_cmp dup/linked.expect dup/linked/.git
 '
 
+test_expect_success 'repair absolute worktree to use relative paths' '
+	test_when_finished "rm -rf main side sidemoved" &&
+	test_create_repo main &&
+	test_commit -C main init &&
+	git -C main worktree add --detach ../side &&
+	echo "../../../../sidemoved/.git" >expect-gitdir &&
+	echo "gitdir: ../main/.git/worktrees/side" >expect-gitfile &&
+	mv side sidemoved &&
+	git -C main worktree repair --relative-paths ../sidemoved &&
+	test_cmp expect-gitdir main/.git/worktrees/side/gitdir &&
+	test_cmp expect-gitfile sidemoved/.git
+'
+
+test_expect_success 'repair relative worktree to use absolute paths' '
+	test_when_finished "rm -rf main side sidemoved" &&
+	test_create_repo main &&
+	test_commit -C main init &&
+	git -C main worktree add --relative-paths --detach ../side &&
+	echo "$(pwd)/sidemoved/.git" >expect-gitdir &&
+	echo "gitdir: $(pwd)/main/.git/worktrees/side" >expect-gitfile &&
+	mv side sidemoved &&
+	git -C main worktree repair ../sidemoved &&
+	test_cmp expect-gitdir main/.git/worktrees/side/gitdir &&
+	test_cmp expect-gitfile sidemoved/.git
+'
+
 test_done
diff --git a/worktree.c b/worktree.c
index cf578c447589425d642fc8aa7a7fa07600e60a70..0d1685b892fcddf74a91304424a94e5ee847388b 100644
--- a/worktree.c
+++ b/worktree.c
@@ -14,6 +14,8 @@ 
 #include "wt-status.h"
 #include "config.h"
 
+int use_relative_paths = 0;
+
 void free_worktree(struct worktree *worktree)
 {
 	if (!worktree)
@@ -379,18 +381,24 @@  int validate_worktree(const struct worktree *wt, struct strbuf *errmsg,
 void update_worktree_location(struct worktree *wt, const char *path_)
 {
 	struct strbuf path = STRBUF_INIT;
+	struct strbuf dotgit = STRBUF_INIT;
+	struct strbuf gitdir = STRBUF_INIT;
 
 	if (is_main_worktree(wt))
 		BUG("can't relocate main worktree");
 
+	strbuf_realpath(&gitdir, git_common_path("worktrees/%s/gitdir", wt->id), 1);
 	strbuf_realpath(&path, path_, 1);
+	strbuf_addf(&dotgit, "%s/.git", path.buf);
 	if (fspathcmp(wt->path, path.buf)) {
-		write_file(git_common_path("worktrees/%s/gitdir", wt->id),
-			   "%s/.git", path.buf);
+		write_worktree_linking_files(dotgit, gitdir);
+
 		free(wt->path);
 		wt->path = strbuf_detach(&path, NULL);
 	}
 	strbuf_release(&path);
+	strbuf_release(&dotgit);
+	strbuf_release(&gitdir);
 }
 
 int is_worktree_being_rebased(const struct worktree *wt,
@@ -569,6 +577,7 @@  static void repair_gitfile(struct worktree *wt,
 			   worktree_repair_fn fn, void *cb_data)
 {
 	struct strbuf dotgit = STRBUF_INIT;
+	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf repo = STRBUF_INIT;
 	struct strbuf backlink = STRBUF_INIT;
 	char *dotgit_contents = NULL;
@@ -586,6 +595,7 @@  static void repair_gitfile(struct worktree *wt,
 
 	strbuf_realpath(&repo, git_common_path("worktrees/%s", wt->id), 1);
 	strbuf_addf(&dotgit, "%s/.git", wt->path);
+	strbuf_addf(&gitdir, "%s/gitdir", repo.buf);
 	dotgit_contents = xstrdup_or_null(read_gitfile_gently(dotgit.buf, &err));
 
 	if (dotgit_contents) {
@@ -603,16 +613,19 @@  static void repair_gitfile(struct worktree *wt,
 		repair = _(".git file broken");
 	else if (fspathcmp(backlink.buf, repo.buf))
 		repair = _(".git file incorrect");
+	else if (use_relative_paths == is_absolute_path(dotgit_contents))
+		repair = _(".git file absolute/relative path mismatch");
 
 	if (repair) {
 		fn(0, wt->path, repair, cb_data);
-		write_file(dotgit.buf, "gitdir: %s", repo.buf);
+		write_worktree_linking_files(dotgit, gitdir);
 	}
 
 done:
 	free(dotgit_contents);
 	strbuf_release(&repo);
 	strbuf_release(&dotgit);
+	strbuf_release(&gitdir);
 	strbuf_release(&backlink);
 }
 
@@ -636,6 +649,45 @@  void repair_worktrees(worktree_repair_fn fn, void *cb_data)
 	free_worktrees(worktrees);
 }
 
+void repair_worktree_after_gitdir_move(struct worktree *wt,
+				       const char *old_path)
+{
+	struct strbuf gitdir = STRBUF_INIT;
+	struct strbuf dotgit = STRBUF_INIT;
+
+	if (is_main_worktree(wt))
+		goto done;
+
+	strbuf_realpath(&gitdir, git_common_path("worktrees/%s/gitdir", wt->id), 1);
+
+	if (strbuf_read_file(&dotgit, gitdir.buf, 0) < 0)
+		goto done;
+
+	strbuf_rtrim(&dotgit);
+	if (!is_absolute_path(dotgit.buf)) {
+		strbuf_insertf(&dotgit, 0, "%s/worktrees/%s/", old_path, wt->id);
+		strbuf_realpath_forgiving(&dotgit, dotgit.buf, 0);
+	}
+
+	if (!file_exists(dotgit.buf))
+		goto done;
+
+	write_worktree_linking_files(dotgit, gitdir);
+done:
+	strbuf_release(&gitdir);
+	strbuf_release(&dotgit);
+}
+
+void repair_worktrees_after_gitdir_move(const char *old_path)
+{
+	struct worktree **worktrees = get_worktrees_internal(1);
+	struct worktree **wt = worktrees + 1; /* +1 skips main worktree */
+
+	for (; *wt; wt++)
+		repair_worktree_after_gitdir_move(*wt, old_path);
+	free_worktrees(worktrees);
+}
+
 static int is_main_worktree_path(const char *path)
 {
 	struct strbuf target = STRBUF_INIT;
@@ -698,12 +750,10 @@  void repair_worktree_at_path(const char *path,
 			     worktree_repair_fn fn, void *cb_data)
 {
 	struct strbuf dotgit = STRBUF_INIT;
-	struct strbuf realdotgit = STRBUF_INIT;
 	struct strbuf backlink = STRBUF_INIT;
 	struct strbuf inferred_backlink = STRBUF_INIT;
 	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf olddotgit = STRBUF_INIT;
-	struct strbuf realolddotgit = STRBUF_INIT;
 	char *dotgit_contents = NULL;
 	const char *repair = NULL;
 	int err;
@@ -715,25 +765,25 @@  void repair_worktree_at_path(const char *path,
 		goto done;
 
 	strbuf_addf(&dotgit, "%s/.git", path);
-	if (!strbuf_realpath(&realdotgit, dotgit.buf, 0)) {
+	if (!strbuf_realpath(&dotgit, dotgit.buf, 0)) {
 		fn(1, path, _("not a valid path"), cb_data);
 		goto done;
 	}
 
-	infer_backlink(realdotgit.buf, &inferred_backlink);
+	infer_backlink(dotgit.buf, &inferred_backlink);
 	strbuf_realpath_forgiving(&inferred_backlink, inferred_backlink.buf, 0);
-	dotgit_contents = xstrdup_or_null(read_gitfile_gently(realdotgit.buf, &err));
+	dotgit_contents = xstrdup_or_null(read_gitfile_gently(dotgit.buf, &err));
 	if (dotgit_contents) {
 		if (is_absolute_path(dotgit_contents)) {
 			strbuf_addstr(&backlink, dotgit_contents);
 		} else {
-			strbuf_addbuf(&backlink, &realdotgit);
+			strbuf_addbuf(&backlink, &dotgit);
 			strbuf_strip_suffix(&backlink, ".git");
 			strbuf_addstr(&backlink, dotgit_contents);
 			strbuf_realpath_forgiving(&backlink, backlink.buf, 0);
 		}
 	} else if (err == READ_GITFILE_ERR_NOT_A_FILE) {
-		fn(1, realdotgit.buf, _("unable to locate repository; .git is not a file"), cb_data);
+		fn(1, dotgit.buf, _("unable to locate repository; .git is not a file"), cb_data);
 		goto done;
 	} else if (err == READ_GITFILE_ERR_NOT_A_REPO) {
 		if (inferred_backlink.len) {
@@ -746,11 +796,11 @@  void repair_worktree_at_path(const char *path,
 			 */
 			strbuf_swap(&backlink, &inferred_backlink);
 		} else {
-			fn(1, realdotgit.buf, _("unable to locate repository; .git file does not reference a repository"), cb_data);
+			fn(1, dotgit.buf, _("unable to locate repository; .git file does not reference a repository"), cb_data);
 			goto done;
 		}
 	} else {
-		fn(1, realdotgit.buf, _("unable to locate repository; .git file broken"), cb_data);
+		fn(1, dotgit.buf, _("unable to locate repository; .git file broken"), cb_data);
 		goto done;
 	}
 
@@ -778,30 +828,28 @@  void repair_worktree_at_path(const char *path,
 	strbuf_addf(&gitdir, "%s/gitdir", backlink.buf);
 	if (strbuf_read_file(&olddotgit, gitdir.buf, 0) < 0)
 		repair = _("gitdir unreadable");
+	else if (use_relative_paths == is_absolute_path(olddotgit.buf))
+		repair = _("gitdir absolute/relative path mismatch");
 	else {
 		strbuf_rtrim(&olddotgit);
-		if (is_absolute_path(olddotgit.buf)) {
-			strbuf_addbuf(&realolddotgit, &olddotgit);
-		} else {
-			strbuf_addf(&realolddotgit, "%s/%s", backlink.buf, olddotgit.buf);
-			strbuf_realpath_forgiving(&realolddotgit, realolddotgit.buf, 0);
+		if (!is_absolute_path(olddotgit.buf)) {
+			strbuf_insertf(&olddotgit, 0, "%s/", backlink.buf);
+			strbuf_realpath_forgiving(&olddotgit, olddotgit.buf, 0);
 		}
-		if (fspathcmp(realolddotgit.buf, realdotgit.buf))
+		if (fspathcmp(olddotgit.buf, dotgit.buf))
 			repair = _("gitdir incorrect");
 	}
 
 	if (repair) {
 		fn(0, gitdir.buf, repair, cb_data);
-		write_file(gitdir.buf, "%s", realdotgit.buf);
+		write_worktree_linking_files(dotgit, gitdir);
 	}
 done:
 	free(dotgit_contents);
 	strbuf_release(&olddotgit);
-	strbuf_release(&realolddotgit);
 	strbuf_release(&backlink);
 	strbuf_release(&inferred_backlink);
 	strbuf_release(&gitdir);
-	strbuf_release(&realdotgit);
 	strbuf_release(&dotgit);
 }
 
@@ -963,3 +1011,29 @@  int init_worktree_config(struct repository *r)
 	free(main_worktree_file);
 	return res;
 }
+
+void write_worktree_linking_files(struct strbuf dotgit, struct strbuf gitdir)
+{
+	struct strbuf path = STRBUF_INIT;
+	struct strbuf repo = STRBUF_INIT;
+	struct strbuf tmp = STRBUF_INIT;
+
+	strbuf_addbuf(&path, &dotgit);
+	strbuf_strip_suffix(&path, "/.git");
+	strbuf_realpath(&path, path.buf, 1);
+	strbuf_addbuf(&repo, &gitdir);
+	strbuf_strip_suffix(&repo, "/gitdir");
+	strbuf_realpath(&repo, repo.buf, 1);
+
+	if (use_relative_paths) {
+		write_file(gitdir.buf, "%s/.git", relative_path(path.buf, repo.buf, &tmp));
+		write_file(dotgit.buf, "gitdir: %s", relative_path(repo.buf, path.buf, &tmp));
+	} else {
+		write_file(gitdir.buf, "%s/.git", path.buf);
+		write_file(dotgit.buf, "gitdir: %s", repo.buf);
+	}
+
+	strbuf_release(&path);
+	strbuf_release(&repo);
+	strbuf_release(&tmp);
+}
diff --git a/worktree.h b/worktree.h
index 11279d0c8fe249bb30642563bf221a8de7f3b0a3..5929089891c97318a8f5329f7938264c717050d5 100644
--- a/worktree.h
+++ b/worktree.h
@@ -5,6 +5,8 @@ 
 
 struct strbuf;
 
+extern int use_relative_paths;
+
 struct worktree {
 	/* The repository this worktree belongs to. */
 	struct repository *repo;
@@ -131,6 +133,16 @@  typedef void (* worktree_repair_fn)(int iserr, const char *path,
  */
 void repair_worktrees(worktree_repair_fn, void *cb_data);
 
+/*
+ * Repair the linked worktrees after the gitdir has been moved.
+ */
+void repair_worktrees_after_gitdir_move(const char *old_path);
+
+/*
+ * Repair the linked worktree after the gitdir has been moved.
+ */
+void repair_worktree_after_gitdir_move(struct worktree *wt, const char *old_path);
+
 /*
  * Repair administrative files corresponding to the worktree at the given path.
  * The worktree's .git file pointing at the repository must be intact for the
@@ -205,4 +217,16 @@  void strbuf_worktree_ref(const struct worktree *wt,
  */
 int init_worktree_config(struct repository *r);
 
+/**
+ * Write the .git file and gitdir file that links the worktree to the repository.
+ *
+ * The `dotgit` parameter is the path to the worktree's .git file, and `gitdir`
+ * is the path to the repository's `gitdir` file.
+ *
+ * Example
+ *  dotgit: "/path/to/foo/.git"
+ *  gitdir: "/path/to/repo/worktrees/foo/gitdir"
+ */
+void write_worktree_linking_files(struct strbuf dotgit, struct strbuf gitdir);
+
 #endif