Skip to content

Fix type hint for image reader #8646

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Kirscher wants to merge 3 commits into
base: dev
Choose a base branch
from
Open

Fix type hint for image reader #8646

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
bf06a4f
Fix type hint for image reader
Kirscher Nov 30, 2025
1a58715
Merge branch 'dev' into fix/image-reader-type-hint
ericspod Dec 1, 2025
338ef11
Merge branch 'dev' into fix/image-reader-type-hint
ericspod Dec 5, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 10 additions & 9 deletions monai/data/image_reader.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@
from collections.abc import Callable, Iterable, Iterator, Sequence
from dataclasses import dataclass
from pathlib import Path
from typing import TYPE_CHECKING, Any
from typing import TYPE_CHECKING, Any, Union

import numpy as np
from torch.utils.data._utils.collate import np_str_obj_array_pattern
Expand Down Expand Up @@ -57,6 +57,13 @@
cp, has_cp = optional_import("cupy")
kvikio, has_kvikio = optional_import("kvikio")

if TYPE_CHECKING:
import cupy

NdarrayOrCupy = Union[np.ndarray, cupy.ndarray]
Copy link
Member

@ericspod ericspod Dec 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This was done to get around Cupy being an optional dependency, this makes it necessary when type checking but this might not be avoidable right now. We do need to consider a way of defining placeholder types for optional dependencies so we can type check correctly without these workarounds.

else:
NdarrayOrCupy = Any

__all__ = ["ImageReader", "ITKReader", "NibabelReader", "NumpyReader", "PILReader", "PydicomReader", "NrrdReader"]


Expand Down Expand Up @@ -663,10 +670,7 @@ def get_data(self, data) -> tuple[np.ndarray, dict]:
metadata[MetaKeys.SPATIAL_SHAPE] = data_array.shape
dicom_data.append((data_array, metadata))

# TODO: the actual type is list[np.ndarray | cp.ndarray]
# should figure out how to define correct types without having cupy not found error
# https://github.com/Project-MONAI/MONAI/pull/8188#discussion_r1886645918
img_array: list[np.ndarray] = []
img_array: list[NdarrayOrCupy] = []
compatible_meta: dict = {}

for data_array, metadata in ensure_tuple(dicom_data):
Expand Down Expand Up @@ -1104,10 +1108,7 @@ def get_data(self, img) -> tuple[np.ndarray, dict]:
img: a Nibabel image object loaded from an image file or a list of Nibabel image objects.

"""
# TODO: the actual type is list[np.ndarray | cp.ndarray]
# should figure out how to define correct types without having cupy not found error
# https://github.com/Project-MONAI/MONAI/pull/8188#discussion_r1886645918
img_array: list[np.ndarray] = []
img_array: list[NdarrayOrCupy] = []
compatible_meta: dict = {}

for i, filename in zip(ensure_tuple(img), self.filenames):
Expand Down