`pip install cffi` fails on MSYS2

[tieneupin]

Hi there! I am encountering issues with pip installing cffi in an MSYS2 environment (UCRT64, in my case).

Running pip install cffi returns the following error:

Collecting cffi
  Using cached cffi-1.17.1.tar.gz (516 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Collecting pycparser (from cffi)
  Using cached pycparser-2.22-py3-none-any.whl.metadata (943 bytes)
Using cached pycparser-2.22-py3-none-any.whl (117 kB)
Building wheels for collected packages: cffi
  Building wheel for cffi (pyproject.toml) ... error
  error: subprocess-exited-with-error

  × Building wheel for cffi (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [68 lines of output]
      _configtest.c:2:2: error: #error "not MSVC"
          2 | #error "not MSVC"
            |  ^~~~~
      Note: will not use '__thread' in the C code
      ***** The above error message can be safely ignored.

      C:/msys64/tmp/pip-build-env-0lk6z3p_/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/cffi
      copying src/cffi/api.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/backend_ctypes.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/cffi_opcode.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/commontypes.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/cparser.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/error.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/ffiplatform.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/lock.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/model.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/pkgconfig.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/recompiler.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/setuptools_ext.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/vengine_cpy.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/vengine_gen.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/verifier.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/_imp_emulation.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/_shimmed_dist_utils.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/__init__.py -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/_cffi_include.h -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/parse_c_type.h -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/_embedding.h -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      copying src/cffi/_cffi_errors.h -> build/lib.mingw_x86_64_ucrt_gnu-cpython-312/cffi
      running build_ext
      building '_cffi_backend' extension
      creating build/temp.mingw_x86_64_ucrt_gnu-cpython-312/src/c
      gcc -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 -DFFI_BUILDING=1 -IC:/msys64/home/username/envs/cffi-test/include -IC:/m
sys64/ucrt64/include/python3.12 -c src/c/_cffi_backend.c -o build/temp.mingw_x86_64_ucrt_gnu-cpython
-312/src/c/_cffi_backend.o
      src/c/_cffi_backend.c: In function 'b_do_dlopen':
      src/c/_cffi_backend.c:4568:40: error: passing argument 1 of 'PyUnicode_AsWideChar' from incomp
atible pointer type [-Wincompatible-pointer-types]
       4568 |             sz1 = PyUnicode_AsWideChar((PyUnicodeObject *)filename_unicode,
            |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            |                                        |
            |                                        PyUnicodeObject *
      In file included from C:/msys64/ucrt64/include/python3.12/Python.h:51,
                       from src/c/_cffi_backend.c:2:
      C:/msys64/ucrt64/include/python3.12/unicodeobject.h:286:15: note: expected 'PyObject *' {aka '
struct _object *'} but argument is of type 'PyUnicodeObject *'
        286 |     PyObject *unicode,          /* Unicode object */
            |     ~~~~~~~~~~^~~~~~~
      src/c/_cffi_backend.c:4579:22: warning: 'Py_FileSystemDefaultEncoding' is deprecated [-Wdeprec
ated-declarations]
       4579 |                      Py_FileSystemDefaultEncoding, &filename_or_null, &flags))
            |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
      In file included from C:/msys64/ucrt64/include/python3.12/Python.h:72:
      C:/msys64/ucrt64/include/python3.12/fileobject.h:22:46: note: declared here
         22 | Py_DEPRECATED(3.12) PyAPI_DATA(const char *) Py_FileSystemDefaultEncoding;
            |                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
      error: command 'C:\\msys64\\ucrt64\\bin/gcc.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 cffi
Failed to build cffi
ERROR: Failed to build installable wheels for some pyproject.toml based projects (cffi)

Additionally, it looks like setuptools has removed distutils as of Python 3.12 (link), which is what MSYS2 ships by default now. As such, previous workarounds to installing cffi on MSYS2 that involve using SETUPTOOLS_USE_DISTUTILS=stdlib pip install cffi will no longer work (comment from Issue #90).

While it's possible to download and install MSYS2's own compilation of cffi, that one is installed as a system-wide package, and unless one knows how to rearrange and set up the files, it's not suited for working with virtual Python environments.

Would this be an issue your team would consider looking into and addressing going forwards?

[arigo]

This has been fixed already in 69efd78, but not released yet for some reason. @nitzmahone?

[tieneupin]

@arigo , for what it's worth, at least that is the only line that needs changing when I pip download cffi on v1.17.1 and edit the code. pip install . then works smoothly after that.

Hopefully that commit will make its way into the next version of cffi soon! 🙏

[nitzmahone]

Hrm, I might need to twiddle some notification settings, because I never saw any of those PRs getting filed or merged.

I've been doing some local spot-testing on 3.14 alphas, but with beta coming soon, there'll be a bunch of housekeeping to be done in the next few weeks. Kicking out a 1.17.2 as part of that seems like a good idea.