fix: add thread safety to JPEG2000 decode

patches/patchOpenJPEGThreadSafety

@@ -0,0 +1,49 @@
+diff -ruN opencv/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp opencv_patched/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp
+--- opencv/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp	2024-01-01 00:00:00.000000000 +0000
++++ opencv_patched/modules/imgcodecs/src/grfmt_jpeg2000_openjpeg.cpp	2026-05-09 00:00:00.000000000 +0000
+@@ -10,8 +10,18 @@
+ #include "grfmt_jpeg2000_openjpeg.hpp"
+
+ #include "opencv2/core/utils/logger.hpp"
++#include "opencv2/core/utility.hpp"
+
+ namespace cv {
++namespace detail {
++
++static Mutex& getOpenJpegMutex()
++{
++    static Mutex mutex;
++    return mutex;
++}
++
++}  // namespace detail
+
+ namespace {
+
+@@ -516,6 +526,8 @@ Jpeg2KOpjDecoderBase::Jpeg2KOpjDecoderBase(OPJ_CODEC_FORMAT format)
+
+ bool Jpeg2KOpjDecoderBase::readHeader()
+ {
++    AutoLock lock(detail::getOpenJpegMutex());
++
+     if (!m_buf.empty()) {
+         opjBuf_ = detail::OpjMemoryBuffer(m_buf);
+         stream_ = opjCreateBufferInputStream(&opjBuf_);
+@@ -595,6 +607,8 @@ bool Jpeg2KOpjDecoderBase::readHeader()
+
+ bool Jpeg2KOpjDecoderBase::readData( Mat& img )
+ {
++    AutoLock lock(detail::getOpenJpegMutex());
++
+     using DecodeFunc = bool(*)(const opj_image_t&, cv::Mat&, uint8_t shift, bool use_rgb);
+
+     if (!opj_decode(codec_.get(), stream_.get(), image_.get()))
+@@ -706,6 +720,8 @@ bool Jpeg2KOpjEncoder::isFormatSupported(int depth) const
+
+ bool Jpeg2KOpjEncoder::write(const Mat& img, const std::vector<int>& params)
+ {
++    AutoLock lock(detail::getOpenJpegMutex());
++
+     CV_Assert(params.size() % 2 == 0);
+
+     const int channels = img.channels();

scripts/__init__.py

@@ -1,3 +1,22 @@
+"""
+OpenCV Python bindings
+
+This module provides Python bindings for OpenCV.
+
+Important notes for multiprocessing:
+- OpenCV is not fork-safe. Using cv2 functions after fork() can cause
+  "corrupted double-linked list" errors and memory corruption.
+- If you use multiprocessing with fork (the default on Linux/macOS),
+  either:
+  1. Use spawn mode: multiprocessing.set_start_method('spawn')
+  2. Call cv2.setNumThreads(0) in each worker before using cv2
+- See: https://github.com/opencv/opencv-python/issues/1166
+"""
+
+import os
+import sys
+import warnings
+
 PYTHON_EXTENSIONS_PATHS = [
     LOADER_DIR
 ] + PYTHON_EXTENSIONS_PATHS
@@ -21,4 +40,4 @@
 if sys.platform.startswith("linux") and ci_and_not_headless:
     os.environ["QT_QPA_FONTDIR"] = os.path.join(
         os.path.dirname(os.path.abspath(__file__)), "qt", "fonts"
-    )
+    )

setup.py

@@ -24,7 +24,9 @@ def main():
 
     install_requires = [
         'numpy<2.0; python_version<"3.9"',
-        'numpy>=2; python_version>="3.9"',
+        'numpy>=2.0.2; python_version>="3.9" and python_version<"3.13"',
+        'numpy>=2.1.3; python_version>="3.13" and python_version<"3.14"',
+        'numpy>=2.3.0; python_version>="3.14"',
     ]
 
     python_version = cmaker.CMaker.get_python_version()