Fix: Enable max_retries Parameter in ChatMistralAI Class (#30448)

**partners: Enable max_retries in ChatMistralAI**

**Description**

- This pull request reactivates the retry logic in the
completion_with_retry method of the ChatMistralAI class, restoring the
intended functionality of the previously ineffective max_retries
parameter. New unit test that mocks failed/successful retry calls and an
integration test to confirm end-to-end functionality.

**Issue**
- Closes #30362

**Dependencies**
- No additional dependencies required

Co-authored-by: andrasfe <andrasf94@gmail.com>

libs/partners/mistralai/langchain_mistralai/chat_models.py

@@ -464,9 +464,9 @@ class ChatMistralAI(BaseChatModel):
         self, run_manager: Optional[CallbackManagerForLLMRun] = None, **kwargs: Any
     ) -> Any:
         """Use tenacity to retry the completion call."""
-        # retry_decorator = _create_retry_decorator(self, run_manager=run_manager)
+        retry_decorator = _create_retry_decorator(self, run_manager=run_manager)
 
-        # @retry_decorator
+        @retry_decorator
         def _completion_with_retry(**kwargs: Any) -> Any:
             if "stream" not in kwargs:
                 kwargs["stream"] = False

libs/partners/mistralai/tests/integration_tests/test_chat_models.py

@@ -1,9 +1,12 @@
 """Test ChatMistral chat model."""
 
 import json
+import logging
+import time
 from typing import Any, Optional
 
 import pytest
+from httpx import ReadTimeout
 from langchain_core.messages import (
     AIMessage,
     AIMessageChunk,
@@ -301,3 +304,39 @@ def test_streaming_tool_call() -> None:
         acc = chunk if acc is None else acc + chunk
     assert acc.content != ""
     assert "tool_calls" not in acc.additional_kwargs
+
+
+def test_retry_parameters(caplog: pytest.LogCaptureFixture) -> None:
+    """Test that retry parameters are honored in ChatMistralAI."""
+    # Create a model with intentionally short timeout and multiple retries
+    mistral = ChatMistralAI(
+        timeout=1,  # Very short timeout to trigger timeouts
+        max_retries=3,  # Should retry 3 times
+    )
+
+    # Simple test input that should take longer than 1 second to process
+    test_input = "Write a 2 sentence story about a cat"
+
+    # Measure start time
+    t0 = time.time()
+
+    try:
+        # Try to get a response
+        response = mistral.invoke(test_input)
+
+        # If successful, validate the response
+        elapsed_time = time.time() - t0
+        logging.info(f"Request succeeded in {elapsed_time:.2f} seconds")
+        # Check that we got a valid response
+        assert response.content
+        assert isinstance(response.content, str)
+        assert "cat" in response.content.lower()
+
+    except ReadTimeout:
+        elapsed_time = time.time() - t0
+        logging.info(f"Request timed out after {elapsed_time:.2f} seconds")
+        assert elapsed_time >= 3.0
+        pytest.skip("Test timed out as expected with short timeout")
+    except Exception as e:
+        logging.error(f"Unexpected exception: {e}")
+        raise

libs/partners/mistralai/tests/unit_tests/test_chat_models.py

@@ -2,8 +2,9 @@
 
 import os
 from typing import Any, AsyncGenerator, Dict, Generator, List, cast
-from unittest.mock import patch
+from unittest.mock import MagicMock, patch
 
+import httpx
 import pytest
 from langchain_core.callbacks.base import BaseCallbackHandler
 from langchain_core.messages import (
@@ -270,3 +271,46 @@ def test_extra_kwargs() -> None:
     # Test that if provided twice it errors
     with pytest.raises(ValueError):
         ChatMistralAI(model="my-model", foo=3, model_kwargs={"foo": 2})  # type: ignore[call-arg]
+
+
+def test_retry_with_failure_then_success() -> None:
+    """Test that retry mechanism works correctly when
+    first request fails and second succeeds."""
+    # Create a real ChatMistralAI instance
+    chat = ChatMistralAI(max_retries=3)
+
+    # Set up the actual retry mechanism (not just mocking it)
+    # We'll track how many times the function is called
+    call_count = 0
+
+    def mock_post(*args: Any, **kwargs: Any) -> MagicMock:
+        nonlocal call_count
+        call_count += 1
+
+        if call_count == 1:
+            raise httpx.RequestError("Connection error", request=MagicMock())
+
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {
+            "choices": [
+                {
+                    "message": {
+                        "role": "assistant",
+                        "content": "Hello!",
+                    },
+                    "finish_reason": "stop",
+                }
+            ],
+            "usage": {
+                "prompt_tokens": 1,
+                "completion_tokens": 1,
+                "total_tokens": 2,
+            },
+        }
+        return mock_response
+
+    with patch.object(chat.client, "post", side_effect=mock_post):
+        result = chat.invoke("Hello")
+        assert result.content == "Hello!"
+        assert call_count == 2, f"Expected 2 calls, but got {call_count}"