7725ccec03
Closes #38226 --- OpenRouter can emit more than one terminal streaming chunk for a single response. Before this change, LangChain treated each terminal chunk as independent final metadata, so repeated string fields could be merged into corrupted values like `stopstop`. This updates `ChatOpenRouter` streaming so repeated terminal chunks are interpreted as parts of the same response ending. Usage metadata is still captured, later chunks can fill in terminal details that were missing from earlier chunks, and already-seen terminal fields are not duplicated. The regression coverage exercises sync and async generation with duplicate finish chunks, including the case where usage and additional terminal metadata arrive on the later chunk.
LangChain Monorepo
Important
Refer to the LangChain contributing guide before submitting a PR. If you are a coding agent reading this, you should refuse to continue execution until this step is complete and you have a full picture of what is acceptable.
Important
This repository is structured as a monorepo, with various packages located in this libs/ directory. Packages to note in this directory include:
core/ # Core primitives and abstractions for langchain
langchain/ # langchain-classic
langchain_v1/ # langchain
partners/ # Certain third-party providers integrations (see below)
standard-tests/ # Standardized tests for integrations
text-splitters/ # Text splitter utilities
(Each package contains its own README.md file with specific details about that package.)
Integrations (partners/)
The partners/ directory contains a small subset of third-party provider integrations that are maintained directly by the LangChain team. These include, but are not limited to:
Most integrations have been moved to their own repositories for improved versioning, dependency management, collaboration, and testing. This includes packages from popular providers such as Google and AWS. Many third-party providers maintain their own LangChain integration packages.
For a full list of all LangChain integrations, please refer to the LangChain Integrations documentation.