What did you do before the bug happened? (Steps to reproduce your issue)
    /tmp$ mkdir -p gb/a gb/b
    /tmp$ cd gb/a
    /tmp/gb/a$ git init r
    Initialized empty Git repository in /tmp/gb/a/r/.git/
    /tmp/gb/a$ cd r
    /tmp/gb/a/r$ touch x
    /tmp/gb/a/r$ git add x
    /tmp/gb/a/r$ git commit -am .
    [main (root-commit) 6323b04] .
    1 file changed, 0 insertions(+), 0 deletions(-)
    create mode 100644 x
    /tmp/gb/a/r$ git branch foo
    /tmp/gb/a/r$ git worktree add ../r.foo
    Preparing worktree (new branch 'r.foo')
    HEAD is now at 6323b04 .
    /tmp/gb/a/r$ -r cp ../* ../../b/.
    -bash: -r: command not found
    /tmp/gb/a/r$ cp -a ../* ../../b/.
    /tmp/gb/a/r$ cd ../../b/r
    /tmp/gb/b/r$ git worktree repair ../r.foo
    repair: gitdir incorrect: /tmp/gb/a/r/.git/worktrees/r.foo/gitdir
    repair: .git file incorrect: /tmp/gb/a/r.foo
    /tmp/gb/b/r$ cat .git/worktrees/r.foo/gitdir 
    /tmp/gb/a/r.foo/.git
    /tmp/gb/b/r$ cat ../r.foo/.git
    gitdir: /tmp/gb/a/r/.git/worktrees/r.foo
    /tmp/gb/b/r$ cat ../../a/.git/worktrees/r.foo/gitdir 
    cat: ../../a/.git/worktrees/r.foo/gitdir: No such file or directory
    /tmp/gb/b/r$ cat ../../a/r/.git/worktrees/r.foo/gitdir 
    /tmp/gb/b/r.foo/.git
    /tmp/gb/b/r$ cat ../../a/r.foo/.git
    gitdir: /tmp/gb/b/r/.git/worktrees/r.foo
    /tmp/gb/b/r$ 

What did you expect to happen? (Expected behavior)
    I expected "/tmp/gb/b/r$ git worktree repair ../r.foo" to alter the
    repositories it was run from, ie those under the directory "/tmp/gb/b".

What happened instead? (Actual behavior)
    "/tmp/gb/b/r$ git worktree repair ../r.foo" modified the repositories
    under the directory "/tmp/gb/a".

[System Info]
git version:
git version 2.39.3 (Apple Git-146)
cpu: arm64
no commit associated with this build
sizeof-long: 8
sizeof-size_t: 8
shell-path: /bin/sh
feature: fsmonitor--daemon
uname: Darwin 23.6.0 Darwin Kernel Version 23.6.0: Mon Jul 29 21:14:21 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T8103 arm64
compiler info: clang: 15.0.0 (clang-1500.3.9.4)
libc info: no libc information available
$SHELL (typically, interactive shell): /opt/homebrew/bin/bash


--
Regards,
Russell Stuart