chroma-core/chroma · error · ValueError

Where dict must contain exactly one field, got {len(data)}

Error message

Where dict must contain exactly one field, got {len(data)}

What it means

Error "Where dict must contain exactly one field, got {len(data)}" thrown in chroma-core/chroma.

Source

Thrown at chromadb/execution/expression/operator.py:139

            if len(data["$or"]) == 0:
                raise ValueError("$or requires at least one condition")
            if len(data) > 1:
                raise ValueError(
                    "$or cannot be combined with other fields in the same dict"
                )

            conditions = [Where.from_dict(c) for c in data["$or"]]
            if len(conditions) == 1:
                return conditions[0]
            result = conditions[0]
            for c in conditions[1:]:
                result = result | c
            return result

        else:
            # Single field condition
            if len(data) != 1:
                raise ValueError(
                    f"Where dict must contain exactly one field, got {len(data)}"
                )

            field, condition = next(iter(data.items()))

            if not isinstance(field, str):
                raise TypeError(
                    f"Field name must be a string, got {type(field).__name__}"
                )

            if isinstance(condition, dict):
                # Operator-based condition
                if not condition:
                    raise ValueError(
                        f"Operator dict for field '{field}' cannot be empty"
                    )
                if len(condition) != 1:
                    raise ValueError(

View on GitHub (pinned to aecdd12c8a)

When it happens

Trigger: Thrown at chromadb/execution/expression/operator.py:139 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of chroma-core/chroma@aecdd12c8a (2026-08-16). Data as JSON: /api/errors/e86411d2f3c072ab. Report an issue: GitHub.