Issue 1:
After successfully install OpenCV 4.5.5 from sources, the Python3 bindings is broken:

$ pkg-config --modversion opencv4
4.5.5
$ python3 -c "import cv2; print(cv2.__version__)"
Traceback (most recent call last):
File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'cv2'

If I use version 4.5.4, python bindings are available as expected:

$ git checkout 4.5.4

$ python3 -c "import cv2; print(cv2.__version__)"
4.5.4

System information (version)

OpenCV => 4.5.5 Nighty build

Operating System / Platform => Ubuntu 20.04.3 LTS

Compiler => gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0

Detailed description

Steps to reproduce

update the system

$ sudo apt update
$ sudo apt upgrade

install dependencies:

$ sudo apt install build-essential cmake git pkg-config libgtk-3-dev \
libavcodec-dev libavformat-dev libswscale-dev libv4l-dev \
libxvidcore-dev libx264-dev libjpeg-dev libpng-dev libtiff-dev \
gfortran openexr libatlas-base-dev python3-dev python3-numpy \
libtbb2 libtbb-dev libdc1394-22-dev v4l-utils

clone repos

$ mkdir ~/opencv_build && cd ~/opencv_build

$ git clone https://github.com/opencv/opencv_contrib.git
$ cd opencv_contrib
$ cd ..

$ git clone https://github.com/opencv/opencv.git
$ cd opencv

Checking last commit:

$ git log -1
commit 7f6dcc27458757f36491842b2e3cc5770d526b25 (HEAD -> 4.x, origin/master, origin/HEAD, origin/4.x)
Merge: f2d5d6d24e 5ba9a089e1
Author: Alexander Alekhin <alexander.a.alekhin@gmail.com>
Date: Tue Jan 18 09:55:13 2022 +0000

Merge pull request #21467 from alalek:issue_21448

build

$ mkdir build && cd build

$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_C_EXAMPLES=OFF \
-D INSTALL_PYTHON_EXAMPLES=OFF \
-D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=OFF \
-D OPENCV_GENERATE_PKGCONFIG=ON \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_build/opencv_contrib/modules \
-D BUILD_EXAMPLES=OFF ..

$ make -j4

$ sudo make install

Check install

$ pkg-config --modversion opencv4
4.5.5
$ python3 -c "import cv2; print(cv2.__version__)"
Traceback (most recent call last):
File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'cv2'
$

PS.: output of cmake is:

$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
> -D CMAKE_INSTALL_PREFIX=/usr/local \
> -D INSTALL_C_EXAMPLES=OFF \
> -D INSTALL_PYTHON_EXAMPLES=OFF \
> -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=OFF \
> -D OPENCV_GENERATE_PKGCONFIG=ON \
> -D OPENCV_EXTRA_MODULES_PATH=~/opencv_build/opencv_contrib/modules \
> -D BUILD_EXAMPLES=OFF ..
-- Detected processor: x86_64
-- Could NOT find PythonInterp (missing: PYTHON_EXECUTABLE) (Required is at least version "2.7")
-- Looking for ccache - not found
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found suitable version "1.2.11", minimum required is "1.2.3")
Cleaning INTERNAL cached variable: WEBP_LIBRARY
Cleaning INTERNAL cached variable: WEBP_INCLUDE_DIR
-- Could NOT find OpenJPEG (minimal suitable version: 2.0, recommended version >= 2.3.1). OpenJPEG will be built from sources
-- OpenJPEG: VERSION = 2.4.0, BUILD = opencv-4.5.5-dev-openjp2-2.4.0
-- OpenJPEG libraries will be built from sources: libopenjp2 (version "2.4.0")
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.11")
-- libva: missing va.h header (VA_INCLUDE_DIR)
-- found Intel IPP (ICV version): 2020.0.0 [2020.0.0 Gold]
-- at: /home/debugger/opencv_build/opencv/build/3rdparty/ippicv/ippicv_lnx/icv
-- found Intel IPP Integration Wrappers sources: 2020.0.0
-- at: /home/debugger/opencv_build/opencv/build/3rdparty/ippicv/ippicv_lnx/iw
-- Could not find OpenBLAS include. Turning OpenBLAS_FOUND off
-- Could not find OpenBLAS lib. Turning OpenBLAS_FOUND off
-- Could NOT find Atlas (missing: Atlas_CLAPACK_INCLUDE_DIR)
-- A library with LAPACK API found.
-- Could NOT find JNI (missing: JAVA_AWT_LIBRARY JAVA_JVM_LIBRARY JAVA_INCLUDE_PATH JAVA_INCLUDE_PATH2 JAVA_AWT_INCLUDE_PATH)
-- VTK is not found. Please set -DVTK_DIR in CMake to VTK build directory, or to VTK install subdirectory with VTKConfig.cmake file
-- Checking for module 'gtk+-2.0'
-- No package 'gtk+-2.0' found
-- Checking for module 'libavresample'
-- No package 'libavresample' found
-- Checking for module 'gstreamer-base-1.0'
-- No package 'gstreamer-base-1.0' found
-- Checking for module 'gstreamer-app-1.0'
-- No package 'gstreamer-app-1.0' found
-- Checking for module 'gstreamer-riff-1.0'
-- No package 'gstreamer-riff-1.0' found
-- Checking for module 'gstreamer-pbutils-1.0'
-- No package 'gstreamer-pbutils-1.0' found
-- Checking for module 'gstreamer-video-1.0'
-- No package 'gstreamer-video-1.0' found
-- Checking for module 'gstreamer-audio-1.0'
-- No package 'gstreamer-audio-1.0' found
-- Module opencv_alphamat disabled because the following dependencies are not found: Eigen
-- freetype2: YES (ver 23.1.17)
-- harfbuzz: YES (ver 2.6.4)
-- Could NOT find HDF5 (missing: HDF5_LIBRARIES HDF5_INCLUDE_DIRS) (found version "")
-- Julia not found. Not compiling Julia Bindings.
-- Module opencv_ovis disabled because OGRE3D was not found
-- No preference for use of exported gflags CMake configuration set, and no hints for include/library directories provided. Defaulting to preferring an installed/exported gflags CMake configuration if available.
-- Failed to find installed gflags CMake configuration, searching for gflags build directories exported with CMake.
-- Failed to find gflags - Failed to find an installed/exported CMake configuration for gflags, will perform search for installed gflags components.
-- Failed to find gflags - Could not find gflags include directory, set GFLAGS_INCLUDE_DIR to directory containing gflags/gflags.h
-- Failed to find glog - Could not find glog include directory, set GLOG_INCLUDE_DIR to directory containing glog/logging.h
-- Module opencv_sfm disabled because the following dependencies are not found: Eigen Glog/Gflags
-- Checking for module 'tesseract'
-- No package 'tesseract' found
-- Tesseract: NO
-- Allocator metrics storage type: 'long long'
-- Registering hook 'INIT_MODULE_SOURCES_opencv_dnn': /home/debugger/opencv_build/opencv/modules/dnn/cmake/hooks/INIT_MODULE_SOURCES_opencv_dnn.cmake
-- opencv_dnn: filter out cuda4dnn source code
-- Excluding from source files list: <BUILD>/modules/dnn/layers/layers_common.rvv.cpp
-- imgcodecs: OpenEXR codec is disabled in runtime. Details: https://github.com/opencv/opencv/issues/21326
-- highgui: using builtin backend: GTK3
-- rgbd: Eigen support is disabled. Eigen is Required for Posegraph optimization
-- Found 'misc' Python modules from /home/debugger/opencv_build/opencv/modules/python/package/extra_modules
-- Found 'mat_wrapper;utils' Python modules from /home/debugger/opencv_build/opencv/modules/core/misc/python/package
-- Found 'gapi' Python modules from /home/debugger/opencv_build/opencv/modules/gapi/misc/python/package
-- Found 'misc' Python modules from /home/debugger/opencv_build/opencv/modules/python/package/extra_modules
-- Found 'mat_wrapper;utils' Python modules from /home/debugger/opencv_build/opencv/modules/core/misc/python/package
-- Found 'gapi' Python modules from /home/debugger/opencv_build/opencv/modules/gapi/misc/python/package
--
-- General configuration for OpenCV 4.5.5-dev =====================================
-- Version control: 4.5.5-57-g7f6dcc2745
--
-- Extra modules:
-- Location (extra): /home/debugger/opencv_build/opencv_contrib/modules
-- Version control (extra): 4.5.5-5-gbb3048d5
--
-- Platform:
-- Timestamp: 2022-01-18T13:18:57Z
-- Host: Linux 5.13.0-25-generic x86_64
-- CMake: 3.16.3
-- CMake generator: Unix Makefiles
-- CMake build tool: /usr/bin/make
-- Configuration: RELEASE
--
-- CPU/HW features:
-- Baseline: SSE SSE2 SSE3
-- requested: SSE3
-- Dispatched code generation: SSE4_1 SSE4_2 FP16 AVX AVX2 AVX512_SKX
-- requested: SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKX
-- SSE4_1 (16 files): + SSSE3 SSE4_1
-- SSE4_2 (1 files): + SSSE3 SSE4_1 POPCNT SSE4_2
-- FP16 (0 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVX
-- AVX (4 files): + SSSE3 SSE4_1 POPCNT SSE4_2 AVX
-- AVX2 (31 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2
-- AVX512_SKX (5 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2 AVX_512F AVX512_COMMON AVX512_SKX
--
-- C/C++:
-- Built as dynamic libs?: YES
-- C++ standard: 11
-- C++ Compiler: /usr/bin/c++ (ver 9.3.0)
-- C++ flags (Release): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG
-- C++ flags (Debug): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG
-- C Compiler: /usr/bin/cc
-- C flags (Release): -fsigned-char -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -O3 -DNDEBUG -DNDEBUG
-- C flags (Debug): -fsigned-char -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -msse -msse2 -msse3 -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUG
-- Linker flags (Release): -Wl,--exclude-libs,libippicv.a -Wl,--exclude-libs,libippiw.a -Wl,--gc-sections -Wl,--as-needed
-- Linker flags (Debug): -Wl,--exclude-libs,libippicv.a -Wl,--exclude-libs,libippiw.a -Wl,--gc-sections -Wl,--as-needed
-- ccache: NO
-- Precompiled headers: NO
-- Extra dependencies: dl m pthread rt
-- 3rdparty dependencies:
--
-- OpenCV modules:
-- To be built: aruco barcode bgsegm bioinspired calib3d ccalib core datasets dnn dnn_objdetect dnn_superres dpm face features2d flann freetype fuzzy gapi hfs highgui img_hash imgcodecs imgproc intensity_transform line_descriptor mcc ml objdetect optflow phase_unwrapping photo plot python3 quality rapid reg rgbd saliency shape stereo stitching structured_light superres surface_matching text tracking video videoio videostab wechat_qrcode xfeatures2d ximgproc xobjdetect xphoto
-- Disabled: world
-- Disabled by dependency: -
-- Unavailable: alphamat cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev cvv hdf java julia matlab ovis python2 sfm ts viz
-- Applications: apps
-- Documentation: NO
-- Non-free algorithms: NO
--
-- GUI: GTK3
-- GTK+: YES (ver 3.24.20)
-- GThread : YES (ver 2.64.6)
-- GtkGlExt: NO
-- VTK support: NO
--
-- Media I/O:
-- ZLib: /usr/lib/x86_64-linux-gnu/libz.so (ver 1.2.11)
-- JPEG: /usr/lib/x86_64-linux-gnu/libjpeg.so (ver 80)
-- WEBP: build (ver encoder: 0x020f)
-- PNG: /usr/lib/x86_64-linux-gnu/libpng.so (ver 1.6.37)
-- TIFF: /usr/lib/x86_64-linux-gnu/libtiff.so (ver 42 / 4.1.0)
-- JPEG 2000: build (ver 2.4.0)
-- OpenEXR: build (ver 2.3.0)
-- HDR: YES
-- SUNRASTER: YES
-- PXM: YES
-- PFM: YES
--
-- Video I/O:
-- DC1394: YES (2.2.5)
-- FFMPEG: YES
-- avcodec: YES (58.54.100)
-- avformat: YES (58.29.100)
-- avutil: YES (56.31.100)
-- swscale: YES (5.5.100)
-- avresample: NO
-- GStreamer: NO
-- v4l/v4l2: YES (linux/videodev2.h)
--
-- Parallel framework: pthreads
--
-- Trace: YES (with Intel ITT)
--
-- Other third-party libraries:
-- Intel IPP: 2020.0.0 Gold [2020.0.0]
-- at: /home/debugger/opencv_build/opencv/build/3rdparty/ippicv/ippicv_lnx/icv
-- Intel IPP IW: sources (2020.0.0)
-- at: /home/debugger/opencv_build/opencv/build/3rdparty/ippicv/ippicv_lnx/iw
-- VA: NO
-- Lapack: NO
-- Eigen: NO
-- Custom HAL: NO
-- Protobuf: build (3.19.1)
--
-- OpenCL: YES (no extra features)
-- Include path: /home/debugger/opencv_build/opencv/3rdparty/include/opencl/1.2
-- Link libraries: Dynamic load
--
-- Python 3:
-- Interpreter: /usr/bin/python3 (ver 3.8.10)
-- Libraries: /usr/lib/x86_64-linux-gnu/libpython3.8.so (ver 3.8.10)
-- numpy: /usr/lib/python3/dist-packages/numpy/core/include (ver 1.17.4)
-- install path: lib/python3.8/site-packages/cv2/python-3.8
--
-- Python (for build): /usr/bin/python3
--
-- Java:
-- ant: NO
-- JNI: NO
-- Java wrappers: NO
-- Java tests: NO
--
-- Install to: /usr/local
-- -----------------------------------------------------------------
--
-- Configuring done
-- Generating done
-- Build files have been written to: /home/debugger/opencv_build/opencv/build

Issue submission checklist

[X ] I report the issue, it's not a question

[X ] I checked the problem with documentation, FAQ, open issues,

forum.opencv.org, Stack Overflow, etc and have not found solution

[X ] I updated to latest OpenCV version and the issue is still there

[X ] There is reproducer code and related data files: videos, images, onnx, etc

Issue 2:
System information (version)

OpenCV => 4.5.5

Operating System / Platform => Raspberry Pi OS Bullseye (32-bit)

Compiler => gcc 10.2.1

Detailed description

On Raspberry Pi OS Bullseye (32-bit), OpenCV 4.5.5 Python 3 packages are installed to lib/python3.9/site-packages/cv2/python-3.9 instead of lib/python3.9/dist-packages/cv2/python-3.9. Issue happened since OpenCV 4.5.5. OpenCV 4.5.4 Python 3 packages was found successfully because installation directory is lib/python3.9/dist-packages/cv2/python-3.9.

I think issue related with d6891c7#diff-d55511776794dc61d4962ae7a9025c0fa54a10b3db01de0079c6ad031f259851R180 (#21219)

Other Debian-based Linux distributions might be affected as well.

Steps to reproduce

python3 -c "from sysconfig import *; print(get_path('purelib'))"

Output: /usr/lib/python3.8/site-packages