feat(deps): bump supported LangChain versions to 0.3.20

Add compatibility test script to verify functionality across different LangChain versions

.github/workflows/test.yml

@@ -60,3 +60,34 @@ jobs:
     - name: Test build
       run: |
         poetry build
+
+  backwards-compatibility:
+    runs-on: ubuntu-latest
+    name: Minimum versions compatibility test
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python 3.10
+      uses: actions/setup-python@v5
+      with:
+        python-version: "3.10"
+
+    - name: Cache poetry install
+      uses: actions/cache@v4
+      with:
+        path: ~/.local
+        key: poetry-compatibility
+
+    - uses: snok/install-poetry@v1
+      with:
+        virtualenvs-create: true
+        virtualenvs-in-project: true
+
+    - name: Install dependencies
+      run: poetry install --no-interaction
+
+    - name: Test compatibility with minimum versions
+      env:
+        LAKERA_GUARD_API_KEY: ${{ secrets.LAKERA_GUARD_API_KEY }}
+        OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
+      run: ./scripts/test_compatibility.sh

lakera_chainguard/lakera_chainguard.py

@@ -6,14 +6,15 @@
 
 import requests
 from langchain.agents import AgentExecutor
-from langchain.schema import BaseMessage, PromptValue
+from langchain_core.messages import BaseMessage
+from langchain_core.prompt_values import PromptValue
 from langchain.tools import BaseTool
 from langchain_core.agents import AgentStep
 from langchain.callbacks.manager import (
     CallbackManagerForLLMRun,
     CallbackManagerForChainRun,
 )
-from langchain.schema.agent import AgentFinish, AgentAction
+from langchain_core.agents import AgentFinish, AgentAction
 from langchain_core.language_models import BaseChatModel, BaseLLM
 from langchain_core.messages import AIMessage, HumanMessage, SystemMessage
 from langchain_core.outputs import ChatResult, LLMResult

pyproject.toml

@@ -14,11 +14,11 @@ keywords = ["llm", "langchain", "prompt-injection", "llm-security", "lakera-guar
 [tool.poetry.dependencies]
 python = "^3.10"
 requests = "^2.31.0"
-langchain = "^0.2.10"
-langchain-core = "^0.2.22"
+langchain = ">=0.2.10,<0.4.0"
+langchain-core = ">=0.2.43,<0.4.0"
+langchain-community = ">=0.2.5,<0.4.0"
 types-requests = "^2.31.0.20240106"
 griffe = "0.49.0"
-langchain-community = "0.2.5"
 
 
 [tool.poetry.group.dev.dependencies]
@@ -28,10 +28,10 @@ black = "^23.12.1"
 pre-commit = "^3.6.0"
 ipykernel = "^6.28.0"
 openai = "^1.6.1"
-langchain-openai = "0.1.25"
 mkdocs = "^1.5.3"
 mkdocstrings = {extras = ["python"], version = "^0.24.0"}
 mkdocs-material = "^9.5.3"
+langchain-openai = ">=0.1.25,<0.4.0"
 
 
 [build-system]