Added test that fails on `master`.
`ToolNode` uses `get_type_hints` which doesn't work properly w/ partial
funcs on Python 3.12+
The diff here is nice anyways when we inline the logic.
## Summary
When invoking a tool with a `ToolCall`, the `tool_call_id` is extracted
but was **not forwarded** to callback handlers in `on_tool_start`. This
made it impossible for callback handlers to correlate tool executions
with the original LLM tool calls.
This fix adds `tool_call_id=tool_call_id` to both:
- Sync `run()` method's `on_tool_start` call
- Async `arun()` method's `on_tool_start` call
## Changes
- **`libs/core/langchain_core/tools/base.py`**: Added `tool_call_id`
parameter to `on_tool_start` calls (2 lines)
- **`libs/core/tests/unit_tests/test_tools.py`**: Added 6 comprehensive
tests covering:
- Sync tool invocation via `invoke()`
- Async tool invocation via `ainvoke()`
- `tool_call_id` is `None` when invoked without a ToolCall
- Empty string `tool_call_id` edge case
- Direct `run()` method
- Direct `arun()` method
## Test plan
- [x] All 147 existing tests pass
- [x] 6 new tests added and passing
- [x] Linting passes
Fixes#34168
---
This PR was developed with AI assistance (Claude).
---------
Co-authored-by: Mason Daugherty <github@mdrxy.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
With this we get the correct types for `_runnable_support` annotated
functions.
* return list[BaseMessage] when messages is not None
* return Runnable when messages is None
* typing of function args
# PR Title: fix(core): prevent async task garbage collection (RUF006)
## Description
This PR addresses a cryptic issue (flagged by Ruff rule RUF006) where
`asyncio` tasks created via `loop.create_task` could be garbage
collected mid-execution because no strong reference was maintained.
In `libs/core/langchain_core/language_models/llms.py`, the retry
decorator's `_before_sleep` hook creates a fire-and-forget task for
logging/callbacks. If the garbage collector runs before this task
completes, the task may be destroyed, leading to silent failures.
## Changes
- Introduced a module-level set `_background_tasks` to hold strong
references to running tasks.
- Updated `_before_sleep` to add new tasks to this set.
- Added a `done_callback` to remove the task from the set upon
completion, preventing memory leaks.
## Verification
- Verified logic with a standalone script to ensure tasks are
added/removed from the set correctly.
- This is a standard pattern recommended in the Python `asyncio`
documentation.
## Checklist
- [x] I have read the contributing guidelines.
- [x] I have run tests locally (logic verification).
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Co-authored-by: Mason Daugherty <github@mdrxy.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
- **Description:** if you dont pass in schema= or schema_= to
StrucutredPrompt(...) today you get a confusing KeyError. Raise a more
readable ValueError instead.
- **Issue:** na
- **Dependencies:** na
- **Description:** When formatting an error, `PydanticOutputParser`
dumps json with default `ensure_ascii=True`
- **Issue:** Fixes#34005
- **Dependencies:** None
- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. **We will not consider
a PR unless these three are passing in CI.** See [contribution
guidelines](https://docs.langchain.com/oss/python/contributing) for
more.
Co-authored-by: Mason Daugherty <mason@langchain.dev>
### Description
This PR adds support for configuring HTTP/HTTPS proxies when rendering
Mermaid diagrams as PNG images using the remote Mermaid.INK API. This
enhancement allows users in restricted network environments to access
the API via a proxy, making the remote rendering feature more robust and
accessible.
The changes include:
- Added optional `proxies` parameter to `draw_mermaid_png` and
`_render_mermaid_using_api` functions
- Updated `Graph.draw_mermaid_png` method to support and pass through
proxy configuration
- Enhanced docstrings with usage examples for the new parameter
- Maintained full backward compatibility with existing code
### Usage Example
```python
proxies = {
"http": "http://127.0.0.1:7890",
"https": "http://127.0.0.1:7890"
}
display(Image(chain.get_graph().draw_mermaid_png(proxies=proxies)))
```
### Dependencies
No new dependencies required. Uses existing `requests` library for HTTP
requests.
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Co-authored-by: Mason Daugherty <github@mdrxy.com>
Wasn't immediately obvious that `get_num_tokens_from_messages` adds
additional prefixes to represent user roles in conversation, which adds
to the overall token count.
```python
from langchain_google_genai import GoogleGenerativeAI
llm = GoogleGenerativeAI(model="gemini-2.5-flash")
num_tokens = llm.get_num_tokens("Hello, world!")
print(f"Number of tokens: {num_tokens}")
# Number of tokens: 4
```
```python
from langchain.messages import HumanMessage
messages = [HumanMessage(content="Hello, world!")]
num_tokens = llm.get_num_tokens_from_messages(messages)
print(f"Number of tokens: {num_tokens}")
# Number of tokens: 6
```
Replaces #33618
**Description:** Fixes the bug in the `load()` function where secret
placeholders in plain dicts were not replaced, even if they match a key
in `secrets_map`, and adds a test case.
Example:
```py
obj = {"api_key": "__SECRET_API_KEY__"}
secret_key = "secret_key_1234"
secrets_map = {"__SECRET_API_KEY__": secret_key}
result = load(obj, secrets_map=secrets_map)
```
Before this change, printing `api_key` in `result` would output
`"__SECRET_API_KEY__"`. Now, it will properly output
`"secret_key_1234"`.
**Issue:** Fixes#31804
**Dependencies:** None
`make format`, `make lint`, and `make test` have all passed on my
machine.
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Co-authored-by: Mason Daugherty <github@mdrxy.com>
The `draw_png()` method currently does not support drawing subgraphs.
This PR adds the ability to render subgraph outlines, improving
visualization clarity when working with nested structures.
