Langchain-neo4j

Changed

- Renamed the `type` property to `role` on `Message` nodes in `Neo4jChatMessageHistory`.
- Updated `GraphCypherQAChain` to use the same schema format as `Neo4jGraph`.
- Replaced code used to query vector and full text indexes in the `vectorstores.neo4j_vector` module with equivalents from the `neo4j-graphrag` package.
- Replaced database schema retrieval code in the `graphs.neo4j_graph` module with equivalents from the `neo4j-graphrag` package.
- Replaced the Cypher queries in `Neo4jChatMessageHistory` with equivalents from the `neo4j-graphrag` package.
- Updated the `construct_schema` function used by the `GraphCypherQAChain` to use schema retrieval functions from the `neo4j-graphrag` package.
- Replaced the legacy `extract_cypher` function with the improved version from `neo4j-graphrag` package.

Added

- Introduced a `delete_session_node` parameter to the `clear` method in `Neo4jChatMessageHistory` for optional deletion of the `Session` node.
- Added `neo4j-graphrag` to the dependencies.

Added

- Optional parameter to specify embedding dimension in `Neo4jVector`, avoiding the need to query the embedding model.

Changed

- Made the `source` parameter of `GraphDocument` optional and updated related methods to support this.
- Suppressed AggregationSkippedNull warnings raised by the Neo4j driver in the `Neo4jGraph` class when fetching the enhanced_schema.
- Modified the `Neo4jGraph` class's enhanced schema Cypher query to utilize the apoc.meta.graph procedure instead of apoc.meta.graphSample.
- Updated `GraphStore` to be a Protocol, enabling compatibility with `GraphCypherQAChain` without requiring inheritance.

Fixed

- Resolved syntax errors in `GraphCypherQAChain` by ensuring node labels with spaces are correctly quoted in Cypher queries.
- Added missing Lucene special character '/' to the list of characters escaped in `remove_lucene_chars`.

Added

- Enhanced Neo4j driver connection management with more robust error handling.
- Simplified connection state checking in Neo4jGraph.
- Introduced `effective_search_ratio` parameter in Neo4jVector to enhance query accuracy by adjusting the candidate pool size during similarity searches.

Fixed

- Removed deprecated LLMChain from GraphCypherQAChain to resolve instantiation issues with the use_function_response parameter.
- Removed unnecessary type: ignore comments, improving type safety and code clarity.

Changed

- Removed dependency on LangChain Community package by integrating necessary components directly into the LangChain Neo4j codebase.

Updated

- Fixed bugs in the Neo4jVector and GraphCypherQAChain classes preventing these classes from working with versions < 5.23 of Neo4j.

Added

- Migrated all Neo4j-related code, including tests and integration tests, from the LangChain Community package to this package.