c68796579e
**Description:** Fixes infinite recursion issue in JSON schema
dereferencing when objects contain both $ref and other properties (e.g.,
nullable, description, additionalProperties). This was causing Apollo
MCP server schemas to hang indefinitely during tool binding.
**Problem:**
- Commit fb5da8384 changed the condition from `set(obj.keys()) ==
{"$ref"}` to `"$ref" in set(obj.keys())`
- This caused objects with $ref + other properties to be treated as pure
$ref nodes
- Result: other properties were lost and infinite recursion occurred
with complex schemas
**Solution:**
- Restore pure $ref detection for objects with only $ref key
- Add proper handling for mixed $ref objects that preserves all
properties
- Merge resolved reference content with other properties
- Maintain cycle detection to prevent infinite recursion
**Impact:**
- Fixes Apollo MCP server schema integration
- Resolves tool binding infinite recursion with complex GraphQL schemas
- Preserves backward compatibility with existing functionality
- No performance impact - actually improves handling of complex schemas
**Issue:** Fixes #32511
**Dependencies:** None
**Testing:**
- Added comprehensive unit tests covering mixed $ref scenarios
- All existing tests pass (1326 passed, 0 failed)
- Tested with realistic Apollo GraphQL schemas
- Stress tested with 100 iterations of complex schemas
**Verification:**
- ✅ `make format` - All files properly formatted
- ✅ `make lint` - All linting checks pass
- ✅ `make test` - All 1326 unit tests pass
- ✅ No breaking changes - full backwards compatibility maintained
---------
Co-authored-by: Marcus <marcus@Marcus-M4-MAX.local>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
🦜🍎️ LangChain Core
Quick Install
pip install langchain-core
What is it?
LangChain Core contains the base abstractions that power the the LangChain ecosystem.
These abstractions are designed to be as modular and simple as possible.
The benefit of having these abstractions is that any provider can implement the required interface and then easily be used in the rest of the LangChain ecosystem.
For full documentation see the API reference.
⛰️ Why build on top of LangChain Core?
The LangChain ecosystem is built on top of langchain-core. Some of the benefits:
- Modularity: We've designed Core around abstractions that are independent of each other, and not tied to any specific model provider.
- Stability: We are committed to a stable versioning scheme, and will communicate any breaking changes with advance notice and version bumps.
- Battle-tested: Core components have the largest install base in the LLM ecosystem, and are used in production by many companies.
1️⃣ Core Interface: Runnables
The concept of a Runnable is central to LangChain Core – it is the interface that most LangChain Core components implement, giving them
- A common invocation interface (
invoke(),batch(),stream(), etc.) - Built-in utilities for retries, fallbacks, schemas and runtime configurability
- Easy deployment with LangGraph
For more check out the Runnable docs. Examples of components that implement the interface include: Chat Models, Tools, Retrievers, and Output Parsers.
📕 Releases & Versioning
As langchain-core contains the base abstractions and runtime for the whole LangChain ecosystem, we will communicate any breaking changes with advance notice and version bumps. The exception for this is anything in langchain_core.beta. The reason for langchain_core.beta is that given the rate of change of the field, being able to move quickly is still a priority, and this module is our attempt to do so.
Minor version increases will occur for:
- Breaking changes for any public interfaces NOT in
langchain_core.beta
Patch version increases will occur for:
- Bug fixes
- New features
- Any changes to private interfaces
- Any changes to
langchain_core.beta
💁 Contributing
As an open-source project in a rapidly developing field, we are extremely open to contributions, whether it be in the form of a new feature, improved infrastructure, or better documentation.
For detailed information on how to contribute, see the Contributing Guide.