Summary

Fixes two issues that cause import cv2 to fail when building OpenCV with -DBUILD_opencv_gapi=OFF -DWITH_GAPI=OFF.

PR #26633 added required_modules filtering to the typing stubs generator, which addressed the main problem. However, two issues remain:

1. Wrong variable in has_all_required_modules() (generation.py)

The function parameter is named type_node but the body uses node — the loop variable from the enclosing scope:

def has_all_required_modules(type_node: TypeNode) -> bool:
    return all(em in root.namespaces for em in node.required_modules)
    #                                          ^^^^ should be type_node

This works by accident because the function is only called as has_all_required_modules(node), so the closure variable node happens to equal the argument. Fixed by using type_node.required_modules.

2. __load_extra_py_code_for_module() only catches ImportError (cv2/__init__.py)

When a stale gapi/ submodule directory persists from a previous build (e.g., in incremental builds), the runtime loader discovers it and attempts to import it. The gapi/__init__.py calls cv.gapi_GNetPackage(...) at import time, which raises AttributeError when the gapi C++ bindings are absent. The loader only catches ImportError, so the AttributeError propagates and crashes import cv2.

Fixed by catching (ImportError, AttributeError).

Files Changed

• modules/python/src2/typing_stubs_generation/generation.py — use function parameter instead of closure variable
• modules/python/package/cv2/__init__.py — catch AttributeError in addition to ImportError

Testing

Verified with OpenCV 4.11.0 built with -DBUILD_opencv_gapi=OFF -DWITH_GAPI=OFF:

• import cv2 succeeds without manual post-install cleanup
• No regression with gapi enabled

Resolves #26098