fix(delegation): expose state durability barriers

hermes_state.py

@@ -2877,6 +2877,16 @@ def _reapply_durability_barriers(conn: sqlite3.Connection) -> bool:
         return False
 
 
+def apply_durability_barriers(conn: sqlite3.Connection) -> bool:
+    """Apply state-store durability barriers without changing journal mode.
+
+    This is the public entry point for secondary users of ``state.db`` that
+    must inherit its owner's journal mode while retaining per-connection
+    durability settings.
+    """
+    return _reapply_durability_barriers(conn)
+
+
 @contextmanager
 def _exclusive_repair_db_guard(db_path: Path):
     """Yield one live connection that excludes writers for repair surgery.

tests/tools/test_async_delegation.py

@@ -66,11 +66,8 @@ def _drain_for(delegation_id, timeout=5.0):
     return None
 
 
-def test_schema_init_preserves_shared_state_db_journal_mode(tmp_path, monkeypatch):
+def test_schema_init_preserves_shared_state_db_journal_mode(tmp_path):
     """The delegation ledger is a guest in state.db, not its mode owner."""
-    import hermes_state
-
-    monkeypatch.setattr(hermes_state, "is_sqlite_wal_reset_vulnerable", lambda: False)
     conn = sqlite3.connect(tmp_path / "state.db")
     try:
         assert conn.execute("PRAGMA journal_mode=DELETE").fetchone()[0] == "delete"
@@ -86,6 +83,23 @@ def test_schema_init_preserves_shared_state_db_journal_mode(tmp_path, monkeypatc
         conn.close()
 
 
+def test_schema_init_preserves_shared_state_db_wal_mode(tmp_path):
+    """Schema initialization must not replace an existing WAL mode."""
+    conn = sqlite3.connect(tmp_path / "state.db")
+    try:
+        assert conn.execute("PRAGMA journal_mode=WAL").fetchone()[0] == "wal"
+
+        ad._initialize_schema(conn)
+
+        assert conn.execute("PRAGMA journal_mode").fetchone()[0] == "wal"
+        assert conn.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' "
+            "AND name='async_delegations'"
+        ).fetchone() == ("async_delegations",)
+    finally:
+        conn.close()
+
+
 @pytest.mark.macos_only
 def test_connect_preserves_wal_and_applies_macos_durability_barriers(
     tmp_path, monkeypatch

tools/async_delegation.py

@@ -140,14 +140,17 @@ def _connect() -> sqlite3.Connection:
 
 
 def _initialize_schema(conn: sqlite3.Connection) -> None:
-    from hermes_state import _reapply_durability_barriers
+    from hermes_state import apply_durability_barriers
 
     # state.db's owning SessionDB connection establishes the configured journal
     # mode. This secondary durability ledger must preserve that mode: applying
     # WAL here on every short-lived connection requires an exclusive lock when
     # the file is not already WAL and can collide with live transcript/FTS
-    # writers. The ledger works in either WAL or DELETE mode.
-    _reapply_durability_barriers(conn)
+    # writers. The ledger works in either WAL or DELETE mode; if it opens a new
+    # file first, the default rollback journal remains valid until SessionDB
+    # establishes the configured mode. sqlite3.connect(timeout=10) above also
+    # gives its small transactions a busy handler for ordinary contention.
+    apply_durability_barriers(conn)
     conn.execute(
         """CREATE TABLE IF NOT EXISTS async_delegations (
             delegation_id TEXT PRIMARY KEY,