System Information

OpenCV version: 5.0.0-pre
Operating System / Platform: Ubuntu 24.04
Compiler & compiler version: GCC 14.2.0

Detailed description

When a module optionally depends on the opencv_dnn module, and CV_WRAP functions are conditionally defined using #ifdef HAVE_OPENCV_DNN, the Python binding generator ignores these conditionals and generates bindings for all CV_WRAP functions regardless of the presence of the DNN module. This leads to build errors when the DNN module is not available.

Example:Module definition:

ocv_define_module(objdetect
    opencv_core
    opencv_imgproc
    opencv_3d
    OPTIONAL
        opencv_dnn
    WRAP
        python
        java
        objc
        js
)

Conditional function definition:

#ifdef HAVE_OPENCV_DNN
    /**
     * @brief Set the net which will be used to find the approximate
     * bounding boxes for the color charts.
     * @param net the neural network.
     */
    CV_WRAP static Ptr<CCheckerDetector> create(const dnn::Net &net);
#endif

Current Behavior:

• Python binding generator ignores #ifdef HAVE_OPENCV_DNN.
• Generates bindings for the CV_WRAP function unconditionally.
• Build fails due to missing opencv_dnn.

Expected Behavior:

• Python binding generator should respect conditional compilation (#ifdef HAVE_OPENCV_DNN) and only generate bindings if the opencv_dnn module is present.

Steps to reproduce

Build the objdetect module with Python bindings solely (without DNN) in branch 5.x

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)