VectorStore.add_texts fails with iterator

[speleo3]

Checked other resources

• I added a very descriptive title to this issue.
• I searched the LangChain documentation with the integrated search.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

Example Code

from langchain_core.vectorstores import InMemoryVectorStore
from langchain_core.embeddings import FakeEmbeddings

vectorstore = InMemoryVectorStore(FakeEmbeddings(size=10))
ids = vectorstore.add_texts(iter(["foo", "bar"]))  # <-- use iter() here
assert len(ids) == 2

Error Message and Stack Trace (if applicable)

AssertionError

Description

The VectorStore.add_texts type annotation for text is Iterable[str]. But passing an iterator rather than a sequence is like passing an empty list.

langchain/libs/core/langchain_core/vectorstores/base.py

Lines 60 to 62 in 408a930

	def add_texts(
	self,
	texts: Iterable[str],

The fix is to replace texts with texts_ on line 104:

langchain/libs/core/langchain_core/vectorstores/base.py

Line 104 in 408a930

for text, metadata_ in zip(texts, metadatas_)

System Info

System Information

OS: Linux
OS Version: #1 SMP Fri Mar 29 23:14:13 UTC 2024
Python Version: 3.10.12 (main, Sep 11 2024, 15:47:36) [GCC 11.4.0]

Package Information

langchain_core: 0.3.1
langchain: 0.3.0
langchain_community: 0.3.0
langsmith: 0.1.121
langchain_chroma: 0.1.4
langchain_huggingface: 0.1.0
langchain_openai: 0.2.0
langchain_text_splitters: 0.3.0
langchain_unstructured: 0.1.4

Optional packages not installed

langgraph
langserve

Other Dependencies

aiohttp: 3.10.5
async-timeout: 4.0.3
chromadb: 0.5.3
dataclasses-json: 0.6.7
fastapi: 0.112.4
httpx: 0.27.2
huggingface-hub: 0.24.7
jsonpatch: 1.33
numpy: 1.26.4
openai: 1.46.0
orjson: 3.10.7
packaging: 23.2
pydantic: 2.9.2
pydantic-settings: 2.5.2
PyYAML: 6.0.2
requests: 2.32.3
sentence-transformers: 3.1.0
SQLAlchemy: 2.0.35
tenacity: 8.5.0
tiktoken: 0.7.0
tokenizers: 0.19.1
transformers: 4.44.2
typing-extensions: 4.12.2
unstructured-client: 0.25.9
unstructured[all-docs]: Installed. No version info available.

[eyurtsev]

Use a list please. we haven't updated the type hints properly yet, but it just doesn't make sense passing the pagination logic to the implementation in this case

[eyurtsev]

The correct fix here is to update the type signature for add_texts through out the entire code base to force users to use Sequence for texts, metadata, ids and handle the pagination properly so pagination is not done on the implementation side.