langchain-ai/langgraph · error · ValueError

Text fields must be a list or a string. Got {text_fields}

Error message

Text fields must be a list or a string. Got {text_fields}

What it means

Error "Text fields must be a list or a string. Got {text_fields}" thrown in langchain-ai/langgraph.

Source

Thrown at libs/checkpoint-sqlite/langgraph/store/sqlite/base.py:1497

        """
        raise NotImplementedError(_AIO_ERROR_MSG)


# Helper functions


def _ensure_index_config(
    index_config: SqliteIndexConfig,
) -> tuple[Any, SqliteIndexConfig]:
    """Process and validate index configuration."""
    index_config = index_config.copy()
    tokenized: list[tuple[str, Literal["$"] | list[str]]] = []
    tot = 0
    text_fields = index_config.get("text_fields") or ["$"]
    if isinstance(text_fields, str):
        text_fields = [text_fields]
    if not isinstance(text_fields, list):
        raise ValueError(f"Text fields must be a list or a string. Got {text_fields}")
    for p in text_fields:
        if p == "$":
            tokenized.append((p, "$"))
            tot += 1
        else:
            toks = tokenize_path(p)
            tokenized.append((p, toks))
            tot += len(toks)
    index_config["__tokenized_fields"] = tokenized
    index_config["__estimated_num_vectors"] = tot
    embeddings = ensure_embeddings(
        index_config.get("embed"),
    )
    return embeddings, index_config


_PLACEHOLDER = object()

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/checkpoint-sqlite/langgraph/store/sqlite/base.py:1497 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of langchain-ai/langgraph@38031739e5 (2026-08-26). Data as JSON: /api/errors/6da0e92c46176414. Report an issue: GitHub.