stubs generation fails only in windows github action: ImportError: DLL load failed while importing

[kj4tmp]

I am building an extension module called soem_ext
and get the following error during stubs generation in my github action build log but not when I build/install locally via pip install .

Building Custom Rule D:/a/pyecm/pyecm/CMakeLists.txt
      soem_ext.cpp
         Creating library D:/a/pyecm/pyecm/build/cp310-cp310-win32/Debug/soem_ext.lib and object D:/a/pyecm/pyecm/build/cp310-cp310-win32/Debug/soem_ext.exp
      soem_ext.vcxproj -> D:\a\pyecm\pyecm\build\cp310-cp310-win32\Debug\soem_ext.cp310-win32.pyd
      1>Generating py.typed, D:/a/pyecm/pyecm/pyecm/soem/soem_ext.pyi
      Traceback (most recent call last):
        File "D:\a\pyecm\pyecm\ext\nanobind\src\stubgen.py", line 1391, in <module>
          main()
        File "D:\a\pyecm\pyecm\ext\nanobind\src\stubgen.py", line 1324, in main
          mod_imported = importlib.import_module(mod)
        File "C:\Users\runneradmin\AppData\Local\pypa\cibuildwheel\Cache\nuget-cpython\pythonx86.3.10.11\tools\lib\importlib\__init__.py", line 126, in import_module
          return _bootstrap._gcd_import(name[level:], package, level)
        File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
        File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
        File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
        File "<frozen importlib._bootstrap>", line 674, in _load_unlocked
        File "<frozen importlib._bootstrap>", line 571, in module_from_spec
        File "<frozen importlib._bootstrap_external>", line 1176, in create_module
        File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
      ImportError: DLL load failed while importing soem_ext: The specified module could not be found.
      The system cannot find the batch label specified - VCEnd
    C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Microsoft\VC\v170\Microsoft.CppCommon.targets(237,5): error MSB8066: Custom build for 'D:\a\pyecm\pyecm\build\cp310-cp310-win32\CMakeFiles\29fb6ccff12ecef0ddda84113e707745\py.typed.rule' exited with code 1. [D:\a\pyecm\pyecm\build\cp310-cp310-win32\soem_ext_stub.vcxproj]

These are my relevant sections of my cmakelists:

nanobind_add_module(
  soem_ext
  STABLE_ABI
  NB_STATIC
  pyecm/soem_ext.cpp
)

nanobind_add_stub(
  soem_ext_stub
  MODULE soem_ext
  OUTPUT "${CMAKE_SOURCE_DIR}/pyecm/soem/soem_ext.pyi"
  PYTHON_PATH $<TARGET_FILE_DIR:soem_ext>
  DEPENDS soem_ext
  MARKER_FILE py.typed
)
# Install directive for scikit-build-core

install(TARGETS soem_ext LIBRARY DESTINATION "pyecm/soem")
install(FILES "${CMAKE_SOURCE_DIR}/pyecm/soem/soem_ext.pyi" DESTINATION "pyecm/soem")
install(FILES "${CMAKE_CURRENT_BINARY_DIR}/py.typed" DESTINATION "pyecm/soem")

this is my pyproject.toml

[project]
name = "pyecm"
version = "0.0.1"
authors = [
  { name="Jeff Anderson", email="kj4tmp@gmail.com" },
]
description = "An EtherCAT MainDevice in Python"
readme = "README.md"
requires-python = ">=3.10"
classifiers = [
    "Programming Language :: Python :: 3",
    "License :: OSI Approved :: MIT License",
    "Operating System :: OS Independent",
]
dependencies = ["numpy"]

[build-system]
requires = ["scikit-build-core >=0.9.1", "typing_extensions"]
build-backend = "scikit_build_core.build"

[tool.scikit-build]
# Protect the configuration against future changes in scikit-build-core
minimum-version = "0.9"
cmake.build-type = "Debug"
# Setuptools-style build caching in a local directory
build-dir = "build/{wheel_tag}"

# Build stable ABI wheels for CPython 3.12+
wheel.py-api = "cp312"

[project.urls]
Homepage = "https://github.com/kj4tmp/pyecm"
Issues = "https://github.com/kj4tmp/pyecm/issues"

[tool.cibuildwheel]
# Necessary to see build output from the actual compilation
build-verbosity = 1

# Optional: run pytest to ensure that the package was correctly built
# test-command = "pytest {project}/tests"
# test-requires = "pytest"

# Needed for full C++17 support on macOS
[tool.cibuildwheel.macos.environment]
MACOSX_DEPLOYMENT_TARGET = "10.14"


# pyproject.toml
[tool.pytest.ini_options]
testpaths = [
    "tests",
]

[kj4tmp]

maybe its related to https://stackoverflow.com/questions/63567298/import-error-dll-load-failed-the-specified-module-could-not-be-found ?

[kj4tmp]

might be because the windows build host is 64-bit, and it built a 32-bit wheel, which may be rejected by import

https://stackoverflow.com/questions/69499321/python-error-importing-dll-files-while-py-file-import-is-successful

[kj4tmp]

i added some print statements, namely os.listdir into stubgen, and the module is there for sure

 Module "soem_ext" ..
      sys.path: ['', 'D:\\a\\pyecm\\pyecm\\build\\cp310-cp310-win_amd64\\Release', 'D:\\a\\pyecm\\pyecm', 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\pip-build-env-e9s428ed\\site', 'C:\\Users\\runneradmin\\AppData\\Local\\pypa\\cibuildwheel\\Cache\\nuget-cpython\\python.3.10.11\\tools\\python310.zip', 'C:\\Users\\runneradmin\\AppData\\Local\\pypa\\cibuildwheel\\Cache\\nuget-cpython\\python.3.10.11\\tools\\DLLs', 'C:\\Users\\runneradmin\\AppData\\Local\\pypa\\cibuildwheel\\Cache\\nuget-cpython\\python.3.10.11\\tools\\lib', 'C:\\Users\\runneradmin\\AppData\\Local\\pypa\\cibuildwheel\\Cache\\nuget-cpython\\python.3.10.11\\tools', 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\pip-build-env-e9s428ed\\overlay\\Lib\\site-packages', 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\pip-build-env-e9s428ed\\normal\\Lib\\site-packages']
      ['nanobind-static.lib', 'soem_ext.cp310-win_amd64.pyd', 'soem_ext.exp', 'soem_ext.lib']
        - importing ..
        File "D:\a\pyecm\pyecm\stubgen.py", line 1418, in <module>
          main()
        File "D:\a\pyecm\pyecm\stubgen.py", line 1351, in main
          mod_imported = importlib.import_module(mod)
        File "C:\Users\runneradmin\AppData\Local\pypa\cibuildwheel\Cache\nuget-cpython\python.3.10.11\tools\lib\importlib\__init__.py", line 126, in import_module
          return _bootstrap._gcd_import(name[level:], package, level)
        File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
        File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
        File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
        File "<frozen importlib._bootstrap>", line 674, in _load_unlocked
        File "<frozen importlib._bootstrap>", line 571, in module_from_spec
        File "<frozen importlib._bootstrap_external>", line 1176, in create_module
        File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
      ImportError: DLL load failed while importing soem_ext: The specified module could not be found.

[kj4tmp]

ok i think the error is a missing import during the import of soem_ext, not for the import of soem_ext itself. trying to find missing dependency with dependency walker

[kj4tmp]

oof, forgot the library i am building depends on wpcap.dll (winpcap or npcap). which i guess is causing this import error

[kj4tmp]

i had a missing dependency of npcap which was causing a dll import error due to a missing wpcap.dll among others. I installed npcap in my build environment and the issue resolved