Compilation error on MSYS2 UCRT64/Clang64: static_cast type mismatch for clang_getFileContents and clang_getFileTime

[markusfn]

environment: MSYS2 (ucrt64 and/or clang64), Python 3.12. The error seems to stem from long long vs. long type mismatches for size_t and time_t in the generated binding code. I updated MSYS2 and installed relevant mingw-w64--clang or mingw-w64--gcc packages.

error message: in ucrt64 (it persists in clang64)
$ pip install pybind11-weaver
Collecting pybind11-weaver
Using cached pybind11_weaver-0.1.3-py3-none-any.whl.metadata (8.5 kB)
Collecting pylibclang (from pybind11-weaver)
Using cached pylibclang-316.0.6.tar.gz (191 kB)
Installing build dependencies ... done
Getting requirements to build wheel ... done
Preparing metadata (pyproject.toml) ... done
Collecting PyYAML (from pybind11-weaver)
Using cached pyyaml-6.0.2-cp312-cp312-mingw_x86_64_ucrt_gnu.whl
Collecting pybind11 (from pybind11-weaver)
Using cached pybind11-2.13.6-py3-none-any.whl.metadata (9.5 kB)
Collecting attrs (from pybind11-weaver)
Using cached attrs-25.3.0-py3-none-any.whl.metadata (10 kB)
Using cached pybind11_weaver-0.1.3-py3-none-any.whl (35 kB)
Using cached attrs-25.3.0-py3-none-any.whl (63 kB)
Using cached pybind11-2.13.6-py3-none-any.whl (243 kB)
Building wheels for collected packages: pylibclang
Building wheel for pylibclang (pyproject.toml) ... error
error: subprocess-exited-with-error

× Building wheel for pylibclang (pyproject.toml) did not run successfully.
│ exit code: 1
╰─> [75 lines of output]
F:/msys64/tmp/pip-build-env-15gg08sn/overlay/lib/python3.12/site-packages/setuptools/config/_a
pply_pyprojecttoml.py:82: SetuptoolsDeprecationWarning: project.license as a TOML table is depreca
ted
!!

          ********************************************************************************
          Please use a simple string containing a SPDX expression for `project.license`. You can

also use project.license-files. (Both options available on setuptools>=77.0.0).

          By 2026-Feb-18, you need to update your project and remove deprecated calls
          or your builds will no longer be supported.

          See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for

details.
********************************************************************************

  !!
    corresp(dist, value, root_dir)
  F:/msys64/tmp/pip-build-env-15gg08sn/overlay/lib/python3.12/site-packages/setuptools/config/_a

pply_pyprojecttoml.py:61: SetuptoolsDeprecationWarning: License classifiers are deprecated.
!!

          ********************************************************************************
          Please consider removing the following classifiers in favor of a SPDX license expressi

on:

          License :: OSI Approved :: MIT License

          See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for

details.
********************************************************************************

  !!
    dist._finalize_license_expression()
  F:/msys64/tmp/pip-build-env-15gg08sn/overlay/lib/python3.12/site-packages/setuptools/dist.py:7

59: SetuptoolsDeprecationWarning: License classifiers are deprecated.
!!

          ********************************************************************************
          Please consider removing the following classifiers in favor of a SPDX license expressi

on:

          License :: OSI Approved :: MIT License

          See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for

details.
********************************************************************************

  !!
    self._finalize_license_expression()
  running bdist_wheel
  running build
  running build_py
  creating build/lib.mingw_x86_64_ucrt_gnu-cpython-312/pylibclang
  copying pylibclang/cindex.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/pylibclang
  copying pylibclang/__init__.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/pylibclang
  running egg_info
  writing pylibclang.egg-info/PKG-INFO
  writing dependency_links to pylibclang.egg-info/dependency_links.txt
  writing top-level names to pylibclang.egg-info/top_level.txt
  reading manifest file 'pylibclang.egg-info/SOURCES.txt'
  reading manifest template 'MANIFEST.in'
  writing manifest file 'pylibclang.egg-info/SOURCES.txt'
  running build_ext
  building 'pylibclang._C' extension
  creating build/temp.mingw_x86_64_ucrt_gnu-cpython-312/c_src
  g++ -fno-strict-overflow -Wsign-compare -DNDEBUG -g -O3 -Wall -march=nocona -msahf -mtune=gene

ric -O2 -pipe -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-strong -Wp,-D__USE_MINGW_ANSI_STDIO=1 -O3 -m
arch=nocona -msahf -mtune=generic -O2 -pipe -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-strong -Wp,-D_
_USE_MINGW_ANSI_STDIO=1 -O3 -Ic_src/include/clang/include -IF:/msys64/tmp/pip-build-env-15gg08sn/ove
rlay/lib/python3.12/site-packages/pybind11/include -IF:/msys64/home/Einfacher/venv312/include -IF:/m
sys64/ucrt64/include/python3.12 -c c_src/binding.cc -o build/temp.mingw_x86_64_ucrt_gnu-cpython-312/
c_src/binding.o -fvisibility=hidden -g0 -std=c++17 -Wno-deprecated-declarations
In file included from c_src/binding.cc:7:
c_src/_binding.cc.inc: In lambda function:
c_src/_binding.cc.inc:23398:15: error: invalid 'static_cast' from type 'const char* ()(CXTran
slationUnit, CXFile, size_t)' {aka 'const char* ()(CXTranslationUnitImpl, void*, long long unsign
ed int*)'} to type 'pybind11_weaver::FnPtrT<void, const char*(CXTranslationUnitImpl*, void*, long un
signed int*)>::type' {aka 'const char* ()(CXTranslationUnitImpl, void*, long unsigned int*)'} [-Wt
emplate-body]
23398 | static_cast<pybind11_weaver::FnPtrT<
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23399 | void, const char (CXTranslationUnitImpl , void ,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23400 | unsigned long )>::type>(
| ~~~~~~~~~~~~~~~~~~~~~~~~~
23401 | &clang_getFileContents),
| ~~~~~~~~~~~~~~~~~~~~~~~
c_src/_binding.cc.inc: In lambda function:
c_src/_binding.cc.inc:23580:15: error: invalid 'static_cast' from type 'time_t ()(CXFile)' {a
ka 'long long int ()(void)'} to type 'pybind11_weaver::FnPtrT<void, long int(void)>::type' {aka '
long int ()(void)'} [-Wtemplate-body]
23580 | static_cast<pybind11_weaver::FnPtrT<void, long(void *)>::type>(
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23581 | &clang_getFileTime),
| ~~~~~~~~~~~~~~~~~~~
error: command 'F:\msys64\ucrt64\bin/g++.EXE' failed with exit code 1
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for pylibclang
Failed to build pylibclang

[notice] A new release of pip is available: 25.0.1 -> 25.1.1
[notice] To update, run: python.exe -m pip install --upgrade pip
ERROR: Failed to build installable wheels for some pyproject.toml based projects (pylibclang)