From 2a06f941abb1f2c1f6ec98c123a615ec24cde27c Mon Sep 17 00:00:00 2001
From: Nilesh Patil <128893479+nileshpatil6@users.noreply.github.com>
Date: Thu, 30 Apr 2026 00:45:38 +0530
Subject: [PATCH 1/2] fix(firestore): serialize session state as JSON to avoid
 Firestore reserved field name restrictions

---
 .../firestore/firestore_session_service.py      | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/google/adk/integrations/firestore/firestore_session_service.py b/src/google/adk/integrations/firestore/firestore_session_service.py
index 83b97c33c2..b2b3a16262 100644
--- a/src/google/adk/integrations/firestore/firestore_session_service.py
+++ b/src/google/adk/integrations/firestore/firestore_session_service.py
@@ -15,6 +15,7 @@
 from __future__ import annotations
 
 import asyncio
+import json
 from contextlib import asynccontextmanager
 from datetime import datetime
 from datetime import timezone
@@ -203,7 +204,7 @@ async def create_session(
         "id": session_id,
         "appName": app_name,
         "userId": user_id,
-        "state": session_state,
+        "state": json.dumps(session_state),
         "createTime": now,
         "updateTime": now,
         "revision": 1,
@@ -314,7 +315,10 @@ async def get_session(
         events.append(Event.model_validate(ed))
 
     # Let's continue getting session.
-    session_state = data.get("state", {})
+    raw_state = data.get("state", {})
+    session_state = (
+        json.loads(raw_state) if isinstance(raw_state, str) else raw_state
+    )
 
     # Fetch shared state
     app_ref = self.client.collection(self.app_state_collection).document(
@@ -407,7 +411,12 @@ async def list_sessions(
       data = doc.to_dict()
       if data:
         u_id = data["userId"]
-        s_state = data.get("state", {})
+        raw_s_state = data.get("state", {})
+        s_state = (
+            json.loads(raw_s_state)
+            if isinstance(raw_s_state, str)
+            else raw_s_state
+        )
         u_state = user_states_map.get(u_id, {})
         merged = self._merge_state(app_state, u_state, s_state)
 
@@ -555,7 +564,7 @@ async def _append_txn(transaction: firestore.AsyncTransaction) -> int:
         transaction.update(
             session_ref,
             {
-                "state": session_only_state,
+                "state": json.dumps(session_only_state),
                 "updateTime": firestore.SERVER_TIMESTAMP,
                 "revision": new_revision,
             },

From fe190ce7187b43a313303614b4280d28696bd9b4 Mon Sep 17 00:00:00 2001
From: Nilesh Patil <128893479+nileshpatil6@users.noreply.github.com>
Date: Tue, 5 May 2026 18:15:49 +0530
Subject: [PATCH 2/2] fix(tests): update firestore state assertions to expect
 JSON-serialized string

---
 .../firestore/test_firestore_session_service.py             | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/unittests/integrations/firestore/test_firestore_session_service.py b/tests/unittests/integrations/firestore/test_firestore_session_service.py
index 1445bfe0ef..f70fcd50a8 100644
--- a/tests/unittests/integrations/firestore/test_firestore_session_service.py
+++ b/tests/unittests/integrations/firestore/test_firestore_session_service.py
@@ -14,6 +14,7 @@
 
 from __future__ import annotations
 
+import json
 from unittest import mock
 
 from google.adk.events.event import Event
@@ -117,7 +118,7 @@ async def test_create_session(mock_firestore_client):
   assert args[1]["id"] == session.id
   assert args[1]["appName"] == app_name
   assert args[1]["userId"] == user_id
-  assert args[1]["state"] == {}
+  assert json.loads(args[1]["state"]) == {}
   assert args[1]["createTime"] == firestore.SERVER_TIMESTAMP
   assert args[1]["updateTime"] == firestore.SERVER_TIMESTAMP
 
@@ -324,8 +325,7 @@ async def test_append_event_with_state_delta(mock_firestore_client):
 
   transaction.update.assert_called_once()
   args, kwargs = transaction.update.call_args
-  # In modular Firestore configurations alignments, updating variables mock assertions core setups
-  assert args[1]["state"] == session.state
+  assert json.loads(args[1]["state"]) == session.state
   assert args[1]["updateTime"] == firestore.SERVER_TIMESTAMP