gco: git checkout wrapper that auto-cds into an existing worktree when a branch is already checked out there

gco.sh

# gco - git checkout wrapper that automatically cds into an existing worktree
# when the branch is already checked out there.
#
# Usage: gco <branch>  (drop-in replacement for git checkout)
#
# Instead of:
#   fatal: 'fix/my-branch' is already used by worktree at '/path/to/worktree'
#
# gco will cd directly into the worktree.
gco() {
    local output exit_code worktree_path
    output=$(git checkout "$@" 2>&1)
    exit_code=$?

    if [ $exit_code -eq 0 ]; then
        echo "$output"
        return 0
    fi

    # Extract path from: fatal: 'branch' is already used by worktree at '/path'
    worktree_path=$(echo "$output" | sed -n "s/.*worktree at '\\([^']*\\)'.*/\\1/p")

    if [ -n "$worktree_path" ]; then
        echo "Branch is checked out in worktree. Switching to: $worktree_path"
        cd "$worktree_path" || return 1
        return 0
    fi

    echo "$output" >&2
    return $exit_code
}