[PATCH] worktree: stop supporting moving worktrees manually

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

The current update_linked_gitdir() has a bug that can create "gitdir"
file in non-multi-worktree setup. Instead of fixing this, we step back a
bit. The original design was probably not well thought out. For now, if
the user manually moves a worktree, they have to fix up "gitdir" file
manually or the worktree will get pruned. In future, we probably will
add "git worktree mv" to support this use case.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/git-worktree.txt |  6 ++----
 setup.c                        | 12 ------------
 2 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 5b9ad04..4814f48 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -33,10 +33,8 @@ The working tree's administrative files in the repository (see
 clean up any stale administrative files.
 
 If you move a linked working tree to another file system, or
-within a file system that does not support hard links, you need to run
-at least one git command inside the linked working tree
-(e.g. `git status`) in order to update its administrative files in the
-repository so that they do not get automatically pruned.
+within a file system that does not support hard links, you need to update
+$GIT_DIR/worktrees/<id>/gitdir so that they do not get automatically pruned.
 
 If a linked working tree is stored on a portable device or network share
 which is not always mounted, you can prevent its administrative files from
diff --git a/setup.c b/setup.c
index d343725..6ee2b23 100644
--- a/setup.c
+++ b/setup.c
@@ -434,17 +434,6 @@ static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 	return ret;
 }
 
-static void update_linked_gitdir(const char *gitfile, const char *gitdir)
-{
-	struct strbuf path = STRBUF_INIT;
-	struct stat st;
-
-	strbuf_addf(&path, "%s/gitdir", gitdir);
-	if (stat(path.buf, &st) || st.st_mtime + 24 * 3600 < time(NULL))
-		write_file(path.buf, "%s", gitfile);
-	strbuf_release(&path);
-}
-
 /*
  * Try to read the location of the git directory from the .git file,
  * return path to git directory if found.
@@ -514,7 +503,6 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)
 		error_code = READ_GITFILE_ERR_NOT_A_REPO;
 		goto cleanup_return;
 	}
-	update_linked_gitdir(path, dir);
 	path = real_path(dir);
 
 cleanup_return:
-- 
2.3.0.rc1.137.g477eb31