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fix: typing module enums references#23813

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asmorkalov merged 1 commit intoopencv:4.xfrom
VadimLevin:dev/vlevin/runtime-typing-module
Jun 16, 2023
Merged

fix: typing module enums references#23813
asmorkalov merged 1 commit intoopencv:4.xfrom
VadimLevin:dev/vlevin/runtime-typing-module

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@VadimLevin VadimLevin commented Jun 15, 2023

Enum names exist only during type checking.
During runtime they should be denoted as named integral types

This patch fixes circular import issue introduced by #23798.

Before patch TermCriteria was defined as follows:

TermCriteria = typing.Tuple[cv2.TermCriteria_Type, int, float]
"""Any type providing sequence protocol is supported"""

which works fine during type checking, but introduces runtime failure:

>>> import cv2
...
    TermCriteria = tuple[cv2.TermCriteria_Type, int, float]  # Any type providing sequence protocol is supported
                         ^^^^^^^^^^^^^^^^^^^^^
AttributeError: partially initialized module 'cv2' has no attribute 'TermCriteria_Type' (most likely due to a circular import)

Generated __init__.py after patch will hide cv2.TermCriteria_Type enumeration by typing.TYPE_CHECKNIG guard.

if typing.TYPE_CHECKING:
    TermCriteria_Type = cv2.TermCriteria_Type
else:
    TermCriteria_Type = int

TermCriteria = typing.Tuple[TermCriteria_Type, int, float]
"""Any type providing sequence protocol is supported"""

So everything can be imported without any issues

>>> import cv2
>>> import cv2.typing
>>> cv2.typing.TermCriteria
typing.Tuple[int, int, float]
>>>

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

  • I agree to contribute to the project under Apache 2 License.
  • To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
  • The PR is proposed to the proper branch
  • There is a reference to the original bug report and related work
  • There is accuracy test, performance test and test data in opencv_extra repository, if applicable
    Patch to opencv_extra has the same branch name.
  • The feature is well documented and sample code can be built with the project CMake

@VadimLevin VadimLevin added this to the 4.8.0 milestone Jun 15, 2023
@VadimLevin VadimLevin requested a review from asmorkalov June 15, 2023 17:28
@VadimLevin VadimLevin self-assigned this Jun 15, 2023
@VadimLevin
fix: typing module enums references
a3b6a5b 
Enum names exist only during type checking.
During runtime they should be denoted as named integral types
@VadimLevin VadimLevin force-pushed the dev/vlevin/runtime-typing-module branch from 1db1a9e to a3b6a5b Compare June 15, 2023 18:31
@asmorkalov
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asmorkalov commented Jun 16, 2023 

Python 3.8.0 (default, Dec  9 2021, 17:53:27) 
[GCC 8.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/mnt/projects/Projects/OpenCV/opencv-build/install/lib/python3.8/site-packages/cv2/__init__.py", line 181, in <module>
    bootstrap()
  File "/mnt/projects/Projects/OpenCV/opencv-build/install/lib/python3.8/site-packages/cv2/__init__.py", line 175, in bootstrap
    if __load_extra_py_code_for_module("cv2", submodule, DEBUG):
  File "/mnt/projects/Projects/OpenCV/opencv-build/install/lib/python3.8/site-packages/cv2/__init__.py", line 28, in __load_extra_py_code_for_module
    py_module = importlib.import_module(module_name)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/mnt/projects/Projects/OpenCV/opencv-build/install/lib/python3.8/site-packages/cv2/typing/__init__.py", line 73, in <module>
    MatLike = typing.Union[cv2.mat_wrapper.Mat, numpy.ndarray[typing.Any, numpy.dtype[numpy.generic]]]
TypeError: 'numpy._DTypeMeta' object is not subscriptable

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VadimLevin commented Jun 16, 2023

What NumPy version do you have?

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asmorkalov commented Jun 16, 2023

numpy 1.20.2

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asmorkalov commented Jun 16, 2023

Works for me with Python 3.9 and fresh numpy. There are some runtime issue with older numpy. will file separate issue on it.

@asmorkalov asmorkalov merged commit 003d048 into opencv:4.x Jun 16, 2023
@asmorkalov asmorkalov mentioned this pull request Jul 27, 2023
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