From 4fe1e17038d492be70ca2b4d04406f3b9f7de328 Mon Sep 17 00:00:00 2001
From: Garry Tan <garrytan@gmail.com>
Date: Fri, 14 Aug 2026 20:19:39 -0700
Subject: [PATCH] =?UTF-8?q?fix(slug):=20cached=20identity=20is=20sticky=20?=
 =?UTF-8?q?=E2=80=94=20heal=20ONLY=20the=20provable=20subdir-cache=20bug?=
 =?UTF-8?q?=20shape?=
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The walk-up rewrite recomputed the slug on every run and "healed" the cache
toward the fresh value, which broke the #2212 continuity contract: a project
that used gstack before adopting a git remote would be silently renamed to
the remote-derived slug, orphaning everything under ~/.gstack/projects/.
Cached identity now wins, with one precise exception: when the cached value
equals THIS pwd's basename while the walk-up proves pwd is not the project
root, the entry came from the pre-walk-up subdirectory bug (#1125) and is
recomputed. All four slug contracts pass together (repo-mode #2212,
walk-up #1125, sanitize, user-slug).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 bin/gstack-slug | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/bin/gstack-slug b/bin/gstack-slug
index 0386188d4..12c5b4643 100755
--- a/bin/gstack-slug
+++ b/bin/gstack-slug
@@ -101,6 +101,27 @@ if [[ -z "$SLUG" ]]; then
   PROJECT_ROOT=$(_outermost_project_root "$PROJECT_DIR")
 fi
 
+# 1b. Cached identity is STICKY (#2212): a project that used gstack before it
+#     adopted a git remote keeps its pre-origin slug — recomputing from the
+#     remote here would rename the project mid-life and orphan everything
+#     under ~/.gstack/projects/<slug>/. The ONE exception is the provable
+#     old-bug shape (#1125): the pre-walk-up resolver cached basename(pwd)
+#     for a SUBDIRECTORY of the real project — if the cached value equals this
+#     pwd's basename while the walk-up says pwd is NOT the project root, the
+#     cache came from that bug, not from legitimate identity; fall through and
+#     recompute so it heals.
+if [[ -z "$SLUG" && -f "$CACHE_FILE" ]]; then
+  _CACHED=$(cat "$CACHE_FILE" 2>/dev/null | tr -cd 'a-zA-Z0-9._-')
+  if [[ -n "$_CACHED" ]]; then
+    _PWD_BASE=$(basename "$PROJECT_DIR" | tr -cd 'a-zA-Z0-9._-')
+    if [[ "$_CACHED" == "$_PWD_BASE" && -n "$PROJECT_ROOT" && "$PROJECT_ROOT" != "$PROJECT_DIR" ]]; then
+      : # old-bug shape — recompute below and self-heal the cache
+    else
+      SLUG="$_CACHED"
+    fi
+  fi
+fi
+
 # 2. If we found a project root and it has a git remote, derive slug from the
 #    remote URL (existing logic — kept verbatim, just rooted at PROJECT_ROOT
 #    instead of $PWD so a subdir without its own remote inherits the parent's).