pathwaycom/pathway · error · ValueError

Unknown list objects strategy: {self.list_objects_strategy}

Error message

Unknown list objects strategy: {self.list_objects_strategy}

What it means

Raised inside the Google Drive connector's object listing when self.list_objects_strategy is not one of the known _ListObjectsStrategy members. The match statement over the strategy falls through to the default branch, meaning the enum got an unexpected value (e.g. a raw string instead of the enum, or a value added/renamed across versions).

Source

Thrown at python/pathway/io/gdrive/__init__.py:393

            case _ListObjectsStrategy.FullScan:
                items = self._detect_objects_with_full_scan()

            case _ListObjectsStrategy.SingleObjectRequest:
                item = self._get(self.root)
                if item is None:
                    items = []
                elif item["mimeType"] != MIME_TYPE_FOLDER:
                    items = [item]
                else:
                    logging.error(
                        f"The object {self.root} is not expected to be a folder"
                    )
                    self.list_objects_strategy = _ListObjectsStrategy.TreeTraversal
                    return self.tree()

            case _:
                raise ValueError(
                    f"Unknown list objects strategy: {self.list_objects_strategy}"
                )

        items = self._apply_filters(items)
        items = [extend_metadata(file) for file in items]
        return _GDriveTree({file["id"]: file for file in items})


@dataclass(frozen=True)
class _GDriveTree:
    files: dict[str, GDriveFile]

    def _diff(self, other: _GDriveTree) -> list[GDriveFile]:
        return [file for file in self.files.values() if file["id"] not in other.files]

    def _modified_files(self, previous: _GDriveTree) -> list[GDriveFile]:
        result = []
        for file in self.files.values():

View on GitHub (pinned to fa2f74a464)

Solutions

Pass the enum member, e.g. list_objects_strategy=_ListObjectsStrategy.TreeTraversal (usually via the public pw.io.gdrive.read API rather than internal classes).
Convert config strings to the enum explicitly: strategy = _ListObjectsStrategy[value] wrapped in try/except KeyError with a clear config error.
Align on a single pathway version everywhere if the enum changed across versions.

Example fix

# before
reader = GDriveReader(..., list_objects_strategy="tree")

# after
from pathway.io.gdrive import _ListObjectsStrategy
reader = GDriveReader(..., list_objects_strategy=_ListObjectsStrategy.TreeTraversal)

Defensive patterns

Strategy: type-guard

Validate before calling

from pathway.io.gdrive import _ListObjectsStrategy
if isinstance(list_objects_strategy, str):
    list_objects_strategy = _ListObjectsStrategy[list_objects_strategy]  # raises KeyError if invalid

Type guard

from enum import Enum

def is_valid_list_strategy(s) -> bool:
    return isinstance(s, Enum) and s in _ListObjectsStrategy

Try / catch

try:
    strategy = _ListObjectsStrategy[strategy_name]
except KeyError:
    raise ValueError(
        f"unknown list_objects_strategy {strategy_name!r}; "
        f"valid: {list(_ListObjectsStrategy)}"
    )

Prevention

Prefer the public pw.io.gdrive.read API over internal reader classes.
Convert config strings to enums at the config boundary, not deep in connector code.
Pin the pathway version to avoid enum drift.

When it happens

Trigger: Constructing a GDrive reader where list_objects_strategy is set to a plain string ("tree") or an out-of-enum value instead of _ListObjectsStrategy.TreeTraversal / FlatTraversal; deserializing a strategy from config and passing it through unchecked.

Common situations: Passing strategy names from config files as raw strings; version drift where a strategy constant was renamed; subclassing or monkey-patching the reader with a custom strategy value.

Related errors

AI-assisted analysis of pathwaycom/pathway@fa2f74a464 (2026-08-15). Data as JSON: /api/errors/e4a25393d6bd1bc1. Report an issue: GitHub.