From f2286b7c6af94da457f31ee021b76934245b21c0 Mon Sep 17 00:00:00 2001
From: Charlie <charlie.wh345@gmail.com>
Date: Fri, 17 Apr 2026 10:18:07 +1000
Subject: [PATCH] fix: gstack-upgrade uses ff-only merge before the hard reset

The upgrade flow uses `git reset --hard origin/main` to advance HEAD.
This trips destructive-command blockers (Claude Code PreToolUse hooks,
pre-commit wrappers, /careful, /guard) and can abort auto-upgrades
mid-flow.

Switch to `git merge --ff-only origin/main` as the primary path. Falls
back to the old behavior if fast-forward fails (divergent history,
local commits). Clean global installs never hit the destructive flag.

Also switches `git stash` to `git stash push --include-untracked -m
"pre-upgrade-<date>"` so untracked build artifacts (.bak/, compiled
binaries) don't block the merge, and the stash is self-describing.

Tested on Windows 11 with a Claude Code PreToolUse guard that blocks
destructive git operations. Upgraded from v0.16.2.0 to v0.18.1.0
cleanly via the ff-only path, setup regenerated customizations as
expected.
---
 gstack-upgrade/SKILL.md.tmpl | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/gstack-upgrade/SKILL.md.tmpl b/gstack-upgrade/SKILL.md.tmpl
index 5402a1da3..531d5b44a 100644
--- a/gstack-upgrade/SKILL.md.tmpl
+++ b/gstack-upgrade/SKILL.md.tmpl
@@ -125,9 +125,16 @@ Use the install type and directory detected in Step 2:
 **For git installs** (global-git, local-git):
 ```bash
 cd "$INSTALL_DIR"
-STASH_OUTPUT=$(git stash 2>&1)
+STASH_OUTPUT=$(git stash push --include-untracked -m "pre-upgrade-$(date +%Y-%m-%d)" 2>&1)
 git fetch origin
-git reset --hard origin/main
+# Try fast-forward first. Safer than reset --hard and passes through guard
+# hooks (Claude Code PreToolUse, pre-commit wrappers) that block destructive
+# ops. Falls back to reset for divergent history — no-op when the working
+# tree is clean and there are no local commits, which is the expected state
+# for a global install.
+if ! git merge --ff-only origin/main 2>/dev/null; then
+  git reset --hard origin/main
+fi
 ./setup
 ```
 If `$STASH_OUTPUT` contains "Saved working directory", warn the user: "Note: local changes were stashed. Run `git stash pop` in the skill directory to restore them."