fix(session-start): scope summary lookup to repository identity (#3160)

scripts/hooks/session-start.js

@@ -14,6 +14,7 @@ const {
   getSessionSearchDirs,
   getLearnedSkillsDir,
   getProjectName,
+  getRepoIdentity,
   findFiles,
   ensureDir,
   readFile,
@@ -254,6 +255,7 @@ function pruneExpiredSessions(searchDirs, retentionDays) {
  * Session files written by session-end.js contain header fields like:
  *   **Project:** my-project
  *   **Worktree:** /path/to/project
+ *   **Repo:** /path/to/main-worktree/.git
  *
  * This function reads each session file once, caching its content, and
  * returns both the selected session object and its already-read content
@@ -261,11 +263,18 @@ function pruneExpiredSessions(searchDirs, retentionDays) {
  *
  * Priority (highest to lowest):
  *   1. Exact worktree (cwd) match — most recent
- *   2. Same project name match for legacy sessions without Worktree metadata
- *   3. No injection when sessions belong to a different worktree/project
+ *   2. Repository identity match: the session was recorded in another
+ *      worktree or subdirectory of the same repository. Identity is the
+ *      main worktree's common git dir (issue #3160), taken from the
+ *      recorded **Repo:** field or resolved from the recorded **Worktree:**
+ *      path for older session files. Unrelated repositories never match.
+ *   3. Same project name match for legacy sessions without Worktree/Repo
+ *      metadata
+ *   4. No injection when sessions belong to a different repository
  *
  * Sessions are already sorted newest-first, so the first match in each
- * category wins.
+ * category wins; the scan continues past repository and project matches so
+ * an exact worktree match always takes precedence.
  *
  * @param {Array<Object>} sessions - Deduplicated session list, sorted newest-first.
  * @param {string} cwd - Current working directory (process.cwd()).
@@ -279,7 +288,17 @@ function selectMatchingSession(sessions, cwd, currentProject) {
 
   // Normalize cwd once outside the loop to avoid repeated syscalls
   const normalizedCwd = normalizePath(cwd);
+  const currentRepoId = getRepoIdentity(cwd);
+  const repoIdByWorktree = new Map();
+  const repoIdOfRecordedWorktree = (recordedWorktree) => {
+    if (!repoIdByWorktree.has(recordedWorktree)) {
+      repoIdByWorktree.set(recordedWorktree, getRepoIdentity(recordedWorktree));
+    }
+    return repoIdByWorktree.get(recordedWorktree);
+  };
 
+  let repoMatch = null;
+  let repoMatchContent = null;
   let projectMatch = null;
   let projectMatchContent = null;
   let readableSessions = 0;
@@ -289,9 +308,11 @@ function selectMatchingSession(sessions, cwd, currentProject) {
     if (!content) continue;
     readableSessions++;
 
-    // Extract **Worktree:** field
+    // Extract **Worktree:** and **Repo:** fields
     const worktreeMatch = content.match(/\*\*Worktree:\*\*\s*(.+)$/m);
     const sessionWorktree = worktreeMatch ? worktreeMatch[1].trim() : '';
+    const repoFieldMatch = content.match(/\*\*Repo:\*\*\s*(.+)$/m);
+    const sessionRepo = repoFieldMatch ? repoFieldMatch[1].trim() : '';
 
     // Exact worktree match — best possible, return immediately
     // Normalize both paths to handle symlinks and case-insensitive filesystems
@@ -299,9 +320,24 @@ function selectMatchingSession(sessions, cwd, currentProject) {
       return { session, content, matchReason: 'worktree' };
     }
 
+    // Repository identity match (#3160): the summary lookup is scoped to the
+    // repository, not the cwd path, so a session recorded in worktree A is
+    // eligible in worktree B only when both resolve to the same common git
+    // dir. Unrelated repositories never share.
+    if (!repoMatch && currentRepoId && (sessionRepo || sessionWorktree)) {
+      const sessionRepoId = sessionRepo
+        ? normalizePath(sessionRepo)
+        : repoIdOfRecordedWorktree(sessionWorktree);
+      if (sessionRepoId && sessionRepoId === currentRepoId) {
+        repoMatch = session;
+        repoMatchContent = content;
+      }
+    }
+
     // Project name match is only safe for legacy session files written before
-    // Worktree metadata existed. A different explicit Worktree is not a match.
-    if (!projectMatch && currentProject && !sessionWorktree) {
+    // Worktree/Repo metadata existed. A different explicit Worktree or Repo
+    // is not a match.
+    if (!projectMatch && currentProject && !sessionWorktree && !sessionRepo) {
       const projectFieldMatch = content.match(/\*\*Project:\*\*\s*(.+)$/m);
       const sessionProject = projectFieldMatch ? projectFieldMatch[1].trim() : '';
       if (sessionProject && sessionProject === currentProject) {
@@ -311,6 +347,10 @@ function selectMatchingSession(sessions, cwd, currentProject) {
     }
   }
 
+  if (repoMatch) {
+    return { session: repoMatch, content: repoMatchContent, matchReason: 'repo' };
+  }
+
   if (projectMatch) {
     return { session: projectMatch, content: projectMatchContent, matchReason: 'project' };
   }