fix: Fix the broken langchain importing caused their 1.0.0 release

PiperOrigin-RevId: 822279014

Author: xuanyang15

contributing/samples/langchain_structured_tool_agent/agent.py

@@ -17,17 +17,19 @@
 """
 from google.adk.agents.llm_agent import Agent
 from google.adk.tools.langchain_tool import LangchainTool
-from langchain.tools import tool
+from langchain_core.tools import tool
 from langchain_core.tools.structured import StructuredTool
 from pydantic import BaseModel
 
 
 async def add(x, y) -> int:
+  """Adds two numbers."""
   return x + y
 
 
 @tool
 def minus(x, y) -> int:
+  """Subtracts two numbers."""
   return x - y
 
 

pyproject.toml

@@ -114,7 +114,7 @@ test = [
   "anthropic>=0.43.0",                      # For anthropic model tests
   "kubernetes>=29.0.0",                     # For GkeCodeExecutor
   "langchain-community>=0.3.17",
-  "langgraph>=0.2.60, <= 0.4.10",            # For LangGraphAgent
+  "langgraph>=0.2.60, <0.4.8",              # For LangGraphAgent
   "litellm>=1.75.5, <2.0.0",                # For LiteLLM tests
   "llama-index-readers-file>=0.4.0",        # For retrieval tests
   "openai>=1.100.2",                        # For LiteLLM
@@ -144,7 +144,7 @@ extensions = [
   "crewai[tools];python_version>='3.10'",      # For CrewaiTool
   "docker>=7.0.0",                             # For ContainerCodeExecutor
   "kubernetes>=29.0.0",                        # For GkeCodeExecutor
-  "langgraph>=0.2.60",                         # For LangGraphAgent
+  "langgraph>=0.2.60, <0.4.8",                 # For LangGraphAgent
   "litellm>=1.75.5",                           # For LiteLlm class. Currently has OpenAI limitations. TODO: once LiteLlm fix it
   "llama-index-readers-file>=0.4.0",           # For retrieval using LlamaIndex.
   "llama-index-embeddings-google-genai>=0.3.0",# For files retrieval using LlamaIndex.

src/google/adk/tools/langchain_tool.py

@@ -18,8 +18,8 @@
 from typing import Union
 
 from google.genai import types
-from langchain.agents import Tool
 from langchain_core.tools import BaseTool as LangchainBaseTool
+from langchain_core.tools import Tool
 from langchain_core.tools.structured import StructuredTool
 from typing_extensions import override
 

tests/unittests/tools/test_langchain_tool.py

@@ -12,22 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import pytest
-
-# TODO: Re-enable this test after verifying LangchainTool and
-# LangGraphAgent against langchain's 1.0.0 release.
-pytest.skip(
-    allow_module_level=True,
-    reason="Langchain just made 1.0.0 release that breaks existing import.",
-)
-
-
 from unittest.mock import MagicMock
 
 from google.adk.tools.langchain_tool import LangchainTool
-from langchain.tools import tool
+from langchain_core.tools import tool
 from langchain_core.tools.structured import StructuredTool
 from pydantic import BaseModel
+import pytest
 
 
 @tool