fix(sessions): archive compressed conversation lineages

apps/desktop/src/app/session/hooks/use-session-actions.ts

@@ -866,6 +866,12 @@ export function useSessionActions({
 
       try {
         await setSessionArchived(storedSessionId, true, archived?.profile)
+        // A sidebar refresh can race the optimistic removal while the PATCH is
+        // in flight and briefly reinsert the still-unarchived backend row. Win
+        // that race after the mutation succeeds so right-click → Archive does
+        // not appear to do nothing until the next full refresh.
+        setSessions(prev => prev.filter(s => s.id !== storedSessionId))
+        $pinnedSessionIds.set($pinnedSessionIds.get().filter(id => id !== storedSessionId && id !== archivedPinId))
         notify({ durationMs: 2_000, kind: 'success', message: copy.archived })
       } catch (err) {
         if (archived) {

hermes_state.py

@@ -1715,15 +1715,51 @@ class SessionDB:
         """Archive or unarchive a session.
 
         Archived sessions are hidden from the default session list but keep all
-        their messages — this is a soft hide, not a delete. Returns True when a
-        row was updated.
+        their messages — this is a soft hide, not a delete. For compression
+        chains, archive the whole logical conversation. Desktop lists compression
+        roots projected forward to their latest continuation; updating only the
+        displayed tip lets the still-unarchived root resurrect it on refresh.
+        Returns True when at least one row was updated.
         """
         def _do(conn):
             cursor = conn.execute(
-                "UPDATE sessions SET archived = ? WHERE id = ?",
-                (1 if archived else 0, session_id),
+                """
+                WITH RECURSIVE
+                  ancestors(id) AS (
+                    SELECT ?
+                    UNION
+                    SELECT parent.id
+                    FROM ancestors a
+                    JOIN sessions child ON child.id = a.id
+                    JOIN sessions parent ON parent.id = child.parent_session_id
+                    WHERE parent.end_reason = 'compression'
+                      AND child.started_at >= parent.ended_at
+                  ),
+                  descendants(id) AS (
+                    SELECT ?
+                    UNION
+                    SELECT child.id
+                    FROM descendants d
+                    JOIN sessions parent ON parent.id = d.id
+                    JOIN sessions child ON child.parent_session_id = parent.id
+                    WHERE parent.end_reason = 'compression'
+                      AND child.started_at >= parent.ended_at
+                  ),
+                  lineage(id) AS (
+                    SELECT id FROM ancestors
+                    UNION
+                    SELECT id FROM descendants
+                  )
+                UPDATE sessions
+                SET archived = ?
+                WHERE id IN (SELECT id FROM lineage)
+                """,
+                (session_id, session_id, 1 if archived else 0),
             )
-            return cursor.rowcount
+            rowcount = cursor.rowcount
+            if rowcount is None or rowcount < 0:
+                rowcount = conn.execute("SELECT changes()").fetchone()[0]
+            return rowcount
         rowcount = self._execute_write(_do)
         return rowcount > 0
 

tests/hermes_state/test_session_archiving.py

@@ -0,0 +1,51 @@
+import time
+
+import pytest
+
+from hermes_state import SessionDB
+
+
+@pytest.fixture
+def db(tmp_path):
+    database = SessionDB(tmp_path / "state.db")
+    try:
+        yield database
+    finally:
+        database.close()
+
+
+def _compression_pair(db: SessionDB):
+    base = time.time() - 100
+    db.create_session("root", source="cli")
+    db.create_session("tip", source="cli", parent_session_id="root")
+    db._conn.execute(
+        "UPDATE sessions SET started_at = ?, ended_at = ?, end_reason = 'compression', message_count = 1 WHERE id = 'root'",
+        (base, base + 10),
+    )
+    db._conn.execute(
+        "UPDATE sessions SET started_at = ?, message_count = 1 WHERE id = 'tip'",
+        (base + 20,),
+    )
+    db._conn.commit()
+
+
+def test_archiving_compression_tip_archives_projected_root(db):
+    _compression_pair(db)
+
+    assert db.set_session_archived("tip", True) is True
+
+    assert db.get_session("root")["archived"] == 1
+    assert db.get_session("tip")["archived"] == 1
+    assert [s["id"] for s in db.list_sessions_rich(order_by_last_active=True)] == []
+    assert [s["id"] for s in db.list_sessions_rich(order_by_last_active=True, archived_only=True)] == ["tip"]
+
+
+def test_unarchiving_compression_tip_unarchives_projected_root(db):
+    _compression_pair(db)
+    db.set_session_archived("tip", True)
+
+    assert db.set_session_archived("tip", False) is True
+
+    assert db.get_session("root")["archived"] == 0
+    assert db.get_session("tip")["archived"] == 0
+    assert [s["id"] for s in db.list_sessions_rich(order_by_last_active=True)] == ["tip"]