Fix #30150: Fix Pyright errors in frontend/frontend.py

[sanleo-wq]

Description

This PR fixes issue #30150 by resolving the Pyright errors in the src/openvino/frontend/frontend.py file.

Changes made

• Added proper type annotations with cast() from the typing module
• Used Optional[FrontEnd] instead of Union[FrontEnd, None] for better readability
• Added targeted # type: ignore comments with explanations where there is an inherent type incompatibility between openvino.Model and openvino._pyopenvino.Model
• Removed the file from exclusions in pyproject.toml

Testing

• Removed src/openvino/frontend/frontend.py from the exclusions in pyproject.toml
• Ran Pyright which now reports no errors:

[p-wysocki]

Thank you for the PR! Could you please also regenerate .pyi files as mentioned in the issue description? All you need to do is build OpenVINO with -DENABLE_WHEEL=ON, install that wheel python -m pip install build/wheels/openvino... and either:

• make any commit, and the .pyi files will be automatically regenerated and added to your commit
• run python src/bindings/python/scripts/generate_stub_files.py and git add them manually

[p-wysocki]

Thank you for the PR! Looks good to me.

[rkazants]

looks a lot undesired changes

[rkazants]

looks a lot undesired changes among different files

[p-wysocki]

Why was it needed? Not saying it's unnecessary, I'm curious - it's a new script and something may be missing.

[sanleo-wq]

Because when i ran the file whit the command: python src/bindings/python/scripts/generate_stub_files.py
give e this errors:

Traceback (most recent call last):
File "openvino\src\bindings\python\scripts\generate_pyapi_stubs.py", line 101, in
main()

File "openvino\src\bindings\python\scripts\generate_pyapi_stubs.py", line 98, in main
sanitize_file(file_path)

File "openvino\src\bindings\python\scripts\generate_pyapi_stubs.py", line 25, in sanitize_file
content = file.readlines()

File "Lib\encodings\cp1252.py", line 23, in decode
return codecs.charmap_decode(input,self.errors,decoding_table)[0]

UnicodeDecodeError: 'charmap' codec can't decode byte 0x9d in position 2010: character maps to

The error occurs because the script tries to read files using the default encoding cp1252 in Windows, but some files contain Unicode characters that aren't supported by this encoding.

By explicitly specifying encoding='utf-8' I was able to generate the pyi files.

[p-wysocki]

Thank you for the investigation! The tasks for fixing pyright seemed straightforward, but when reviewing the PRs we decided that it's a much more difficult issue than we expected and, combined with the task priority, we decided to move fixes for pyright checks back as an internal OpenVINO team effort. It's no longer an open Good First Issue - we apologize for closing the task you were working on, your contribution helped us investigate that issue.