[PATCH 0/4] Link worktrees with relative paths

Hello,

This patch series modifies Git's handling of worktree linking to use relative paths instead of absolute paths. The motivation behind this change is to enhance the robustness of worktree links when the main repository is moved, or when used in environments like containerized development where absolute paths differ across systems.

Currently, Git stores absolute paths to both the main repository and the linked worktrees. This causes issues when the repository is moved because the hardcoded paths become invalid, leading to broken worktree links. Developers are then required to manually repair the links by running `git worktree repair`, which can be cumbersome.

By switching to relative paths for worktrees, this patch improves the resilience of worktree links. For self-contained repositories (e.g., bare repositories with worktrees), the links will continue to function properly when the repository is moved or mapped inside a containerized environment. While relativ e paths do not completely eliminate the need for repairs (as links external to the repository can still break), the likelihood is reduced, and Git continues to provide mechanisms to repair broken links when needed.

I have included tests to verify that:
- worktree links are created with relative paths.
- moving the repository does not break worktree links.

Note that absolute paths are still supported, and the code handles both types of paths. There should be no breaking changes introduced with this patch. I considered adding a configuration option (e.g., `worktree.useRelativePaths`) to control path type, but decided to keep it simple. However, if there is interest, I can add this feature.

This series is based on top of 111e864d69.

Thanks!

Caleb

Caleb White (4):
  worktree: refactor infer_backlink() to use *strbuf
  worktree: link worktrees with relative paths
  worktree: sync worktree paths after gitdir move
  worktree: prevent null pointer dereference

 builtin/worktree.c           |  17 +--
 setup.c                      |   2 +-
 t/t2408-worktree-relative.sh |  39 ++++++
 worktree.c                   | 235 +++++++++++++++++++++++++++--------
 worktree.h                   |  10 ++
 5 files changed, 240 insertions(+), 63 deletions(-)
 create mode 100755 t/t2408-worktree-relative.sh