From b273db3fec6f107aa5f640a5614681b6c293bd0e Mon Sep 17 00:00:00 2001
From: Zi Makki <zimakki@gmail.com>
Date: Sun, 12 Jul 2026 23:47:18 +0200
Subject: [PATCH] fix(bootstrap): derive preflight root before function entry

---
 scripts/bootstrap/preflight.zsh | 9 +++++++--
 tests/bootstrap/isolated.sh     | 8 ++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/scripts/bootstrap/preflight.zsh b/scripts/bootstrap/preflight.zsh
index ca98b02..70ddd35 100755
--- a/scripts/bootstrap/preflight.zsh
+++ b/scripts/bootstrap/preflight.zsh
@@ -3,8 +3,13 @@
 # bootstrap exception. Source this file to call
 # bootstrap_require_canonical_checkout; execute it for the full preflight.
 
+# Capture the source path before entering a function. With Zsh's default
+# FUNCTION_ARGZERO behavior, $0 becomes the function name inside a function
+# and cannot be used to locate this file reliably.
+typeset -g _DOTFILES_PREFLIGHT_REPO="${${(%):-%N}:A:h:h:h}"
+
 bootstrap_require_canonical_checkout() {
-  local repo="${1:-${0:A:h:h:h}}"
+  local repo="${1:-$_DOTFILES_PREFLIGHT_REPO}"
   local git_dir common_dir_raw common_dir
 
   repo="$(cd "$repo" && pwd -P)" || return 1
@@ -35,7 +40,7 @@ bootstrap_preflight_main() {
   set -u
   setopt pipe_fail
 
-  local repo="${0:A:h:h:h}"
+  local repo="$_DOTFILES_PREFLIGHT_REPO"
   if [[ "${1:-}" == "--guard-only" ]]; then
     (( $# <= 2 )) || {
       print -u2 -- "usage: $0 --guard-only [repo]"
diff --git a/tests/bootstrap/isolated.sh b/tests/bootstrap/isolated.sh
index 89b502a..ef531a9 100755
--- a/tests/bootstrap/isolated.sh
+++ b/tests/bootstrap/isolated.sh
@@ -114,7 +114,7 @@ text = re.sub(
 path.write_text(text)
 PY
 printf '# intentionally empty fixture\n' > "$guard_primary/BrewFile"
-ln -s "$repo/scripts/bootstrap/preflight.zsh" \
+cp "$repo/scripts/bootstrap/preflight.zsh" \
   "$guard_primary/scripts/bootstrap/preflight.zsh"
 git -C "$guard_primary" add fixture mise.toml BrewFile zshenv config/zsh/zshenv \
   scripts/bootstrap/preflight.zsh scripts/bootstrap/json-overlay.py \
@@ -123,12 +123,12 @@ git -C "$guard_primary" -c user.name=Bootstrap -c user.email=bootstrap@example.i
   commit --quiet -m fixture
 git -C "$guard_primary" worktree add --quiet -b linked-test "$guard_linked"
 guard_linked_real="$(cd "$guard_linked" && pwd -P)"
-zsh "$repo/scripts/bootstrap/preflight.zsh" --guard-only "$guard_primary"
-if zsh "$repo/scripts/bootstrap/preflight.zsh" --guard-only "$guard_linked" >/dev/null 2>&1; then
+zsh "$guard_primary/scripts/bootstrap/preflight.zsh" --guard-only
+if zsh "$guard_linked/scripts/bootstrap/preflight.zsh" --guard-only >/dev/null 2>&1; then
   fail "mutation guard accepted a linked worktree"
 fi
 DOTFILES_BOOTSTRAP_TEST_ALLOW_WORKTREE=1 \
-  zsh "$repo/scripts/bootstrap/preflight.zsh" --guard-only "$guard_linked" >/dev/null
+  zsh "$guard_linked/scripts/bootstrap/preflight.zsh" --guard-only >/dev/null
 pass "canonical checkout passes, linked worktree fails, explicit test override passes"
 
 guard_home="$root/guard-home"