fix: guard reserved sessions and bounded response state

recognization/code/test_api.py

@@ -196,6 +196,31 @@ class RestContractTests(unittest.TestCase):
         self.assertEqual(sent[0]["status"], 413)
         self.assertIn(b"PAYLOAD_TOO_LARGE", sent[1]["body"])
 
+    def test_overflow_after_response_start_sends_no_second_start(self):
+        """A body that overflows after headers began must not start again."""
+        import anyio
+
+        from transport import BodyLimit
+
+        async def app(scope, receive, send):
+            await send({"type": "http.response.start", "status": 200, "headers": []})
+            await receive()
+            await send({"type": "http.response.body", "body": b"ok"})
+
+        sent = []
+
+        async def receive():
+            return {"type": "http.request", "body": b"x" * 40, "more_body": False}
+
+        async def send(message):
+            sent.append(message)
+
+        anyio.run(BodyLimit(app, 8), {"type": "http"}, receive, send)
+        starts = [message for message in sent if message.get("type") == "http.response.start"]
+        self.assertEqual(len(starts), 1)
+        self.assertEqual(starts[0]["status"], 200)
+        self.assertFalse(any(message.get("status") == 413 for message in sent))
+
     def test_classify_and_inspect_roundtrip(self):
         recognized = self.client.post(
             "/v1/recognize?classify=false", content=jpeg_bytes(),
@@ -360,6 +385,16 @@ class WebSocketProtocolTests(unittest.TestCase):
         finally:
             engine.shutdown()
 
+    def test_lifespan_shutdown_skips_a_reserved_slot(self):
+        """A reservation is None until setup finishes. Shutdown must not call it."""
+        client, engine = make_app()
+        client.app.state.sessions["reserved"] = None
+        try:
+            with client:
+                pass
+        finally:
+            engine.shutdown()
+
 
 class LegacyRouteTests(unittest.TestCase):
     def test_legacy_sessions_still_respond(self):