git worktree with relative path?

I have a master and a setup branch in my repo. I'm keeping the setup branch checked out as a worktree inside the main repo folder via

git worktree add ./local/setup
echo '/local' > .gitignore

So the main repo folder is on master, and the local/setup folder is on setup. Everything is fine and dandy, I can work on my setup files without having to switch branches, I can commit from within local/setup etc.

But if I try to move the entire repo, or access it from a different Linux boot (/home/myrepo becomes /mnt/ubu/home/myrepo), things break. The problem seems to be that git's worktree functionality records absolute paths, in

myrepo/.git/worktrees/setup/gitdir
myrepo/local/setup/.git

Can I convert these to relative paths to make the repo + embedded worktree relocatable? I'm not sure what the paths in those files should be relative to, but I can experiment. Is this setup dangerous?

I make a simple bash script for my personal use here:

https://github.com/Kristian-Tan/git-worktree-relative

Note that this answer is just a copy-paste from my README.md

...

My solution

• Bash script to replace the content of {worktree}/.git file and {repo}/.git/worktrees/{wtname}/gitdir
• Why bash: almost everyone who use git will use it in some kind of bash-shell-like environment (ex: bash shell in linux, git bash in windows)
• Requirements (should be available on every bash shell):
  • cat
  • echo
  • readlink
  • realpath (GNU utility since 2012, might not be preinstalled in very old linux system like debian wheezy)
  • sed
  • pwd
  • bash shell parameter expansion ${parameter/pattern/string} and ${parameter%%word} https://www.gnu.org/software/bash/manual/bash.html#Shell-Parameter-Expansion
• Another bash script to change it back to absolute path (since git worktree remove may refuse on relative path)

Usage

• Execute the script in your worktree (or supply the worktree directory path in -w options)
• It will read path to repository from {worktree}/.git file
• Options:
  • -v = verbose (not implemented yet)
  • -w worktree_target = directory of worktree to be made relative (will default to current directory if not supplied)
  • -r repository_target = directory of repository (including worktree directory inside .git, will be read from {worktree_target}/.git file if not supplied)
  • -h = show help
• This solution works for broken link (ex: worktree directory moved OR parent git directory moved): just supply the repository path in -r repositor_target flag
• This solution works for worktree inside parent repository
• example:
  • repository in /home/myuser/repo/myproject ; worktree in /home/myuser/www/myproject ; worktree is connected with repository (link is not broken)

    cd /home/myuser/www/myproject
    git-worktree-relative
    # OR
    git-worktree-relative -w /home/myuser/www/myproject
    

  • repository in /home/myuser/repo/myproject ; worktree in /home/myuser/www/myproject ; worktree is NOT connected with repository (link broken)

    cd /home/myuser/www/myproject
    git-worktree-relative -r /home/myuser/repo/myproject/.git/worktrees/myproject
    # OR
    git-worktree-relative -w /home/myuser/www/myproject -r /home/myuser/repo/myproject/.git/worktrees/myproject
    

  • to detect if link is broken, run command 'git status' in worktree directory
• Reversing relative worktree back to absolute: just change git-worktree-relative command with git-worktree-absolute (same command line argument)
  • command git worktree remove requires the path to be absolute: you can use this reverse script to revert it back to absolute path before removing

Installation

Automatic Installation

• copy paste below command into your terminal:

git clone https://github.com/Kristian-Tan/git-worktree-relative.git
cd git-worktree-relative
sudo bash install.sh

• or this one-line: git clone https://github.com/Kristian-Tan/git-worktree-relative.git ; cd git-worktree-relative ; sudo bash install.sh
• or another one-line: /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Kristian-Tan/git-worktree-relative/HEAD/get)"

Manual Installation

• installation for all users:
  • copy git-worktree-relative.sh and git-worktree-absolute.sh to /usr/bin or /bin (you can also remove the extension)
  • give other user permission to execute it
  • example:

    cp git-worktree-relative.sh /usr/bin/git-worktree-relative
    cp git-worktree-absolute.sh /usr/bin/git-worktree-absolute
    chown root:root /usr/bin/git-worktree-relative
    chown root:root /usr/bin/git-worktree-absolute
    chmod 0755 /usr/bin/git-worktree-relative
    chmod 0755 /usr/bin/git-worktree-absolute
  

• installation for one user:
  • copy it to any directory that is added to your PATH variable

Uninstallation

• just remove copied files (or just use uninstall.sh script: git clone https://github.com/Kristian-Tan/git-worktree-relative.git ; sudo bash git-worktree-relative/uninstall.sh)
• or another one-line: /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Kristian-Tan/git-worktree-relative/HEAD/remove)"

...

Credits

• [REMOVED] Bash implementation of strpos and substr by BR0kEN- (https://gist.github.com/BR0kEN-/a84b18717f8c67ece6f7)
• StackOverflow user usretc for advise in git worktree with relative path?