Attribute error: module 'mesonpy' has no attribute 'prepare_metadata_for_build_wheel'

[arunppsg]

I want to install scipy (which uses meson for build system) via brew in an arm64 machine and I run into this error AttributeError: module 'mesonpy' has no attribute 'prepare_metadata_for_build_wheel'. Here is a traceback:

      Traceback (most recent call last):
        File "/Users/arun/Applications/venv/pyg/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 156, in prepare_metadata_for_build_wheel
          hook = backend.prepare_metadata_for_build_wheel
      AttributeError: module 'mesonpy' has no attribute 'prepare_metadata_for_build_wheel'

The meson version is 0.64.1. Should I use a different version?

[eli-schwartz]

This error comes from the PEP 517 build backend at https://github.com/mesonbuild/meson-python, although technically it's a bug in a library that pip uses called pep517.

The real issue is that this is a terribly confusing error message. All it says is that "the package failed to build due to a previous error".

You do need to post the entire failure log, including the meson error that came before this.

Just posting the traceback says nothing and is a bug in unrelated projects.

[arunppsg]

Here is the full error message

Collecting scipy
  Using cached scipy-1.9.3.tar.gz (42.1 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Installing backend dependencies ... done
  Preparing metadata (pyproject.toml) ... error
  error: subprocess-exited-with-error
  
  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [75 lines of output]
      The Meson build system
      Version: 0.64.1
      Source dir: /private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd
      Build dir: /private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd/.mesonpy-dadizaey/build
      Build type: native build
      Project name: SciPy
      Project version: 1.9.3
      C compiler for the host machine: ccache cc (clang 12.0.5 "Apple clang version 12.0.5 (clang-1205.0.22.11)")
      C linker for the host machine: cc ld64 650.9
      C++ compiler for the host machine: ccache c++ (clang 12.0.5 "Apple clang version 12.0.5 (clang-1205.0.22.11)")
      C++ linker for the host machine: c++ ld64 650.9
      Host machine cpu family: aarch64
      Host machine cpu: aarch64
      Compiler for C supports arguments -Wno-unused-but-set-variable: NO
      Compiler for C supports arguments -Wno-unused-but-set-variable: NO (cached)
      Compiler for C supports arguments -Wno-unused-function: YES
      Compiler for C supports arguments -Wno-conversion: YES
      Compiler for C supports arguments -Wno-misleading-indentation: YES
      Compiler for C supports arguments -Wno-incompatible-pointer-types: YES
      Library m found: YES
      
      ../../meson.build:57:0: ERROR: Unknown compiler(s): [['gfortran'], ['flang'], ['nvfortran'], ['pgfortran'], ['ifort'], ['ifx'], ['g95']]
      The following exception(s) were encountered:
      Running `gfortran --version` gave "[Errno 13] Permission denied: 'gfortran'"
      Running `gfortran -V` gave "[Errno 13] Permission denied: 'gfortran'"
      Running `flang --version` gave "[Errno 2] No such file or directory: 'flang'"
      Running `flang -V` gave "[Errno 2] No such file or directory: 'flang'"
      Running `nvfortran --version` gave "[Errno 2] No such file or directory: 'nvfortran'"
      Running `nvfortran -V` gave "[Errno 2] No such file or directory: 'nvfortran'"
      Running `pgfortran --version` gave "[Errno 2] No such file or directory: 'pgfortran'"
      Running `pgfortran -V` gave "[Errno 2] No such file or directory: 'pgfortran'"
      Running `ifort --version` gave "[Errno 2] No such file or directory: 'ifort'"
      Running `ifort -V` gave "[Errno 2] No such file or directory: 'ifort'"
      Running `ifx --version` gave "[Errno 2] No such file or directory: 'ifx'"
      Running `ifx -V` gave "[Errno 2] No such file or directory: 'ifx'"
      Running `g95 --version` gave "[Errno 2] No such file or directory: 'g95'"
      Running `g95 -V` gave "[Errno 2] No such file or directory: 'g95'"
      
      A full log can be found at /private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd/.mesonpy-dadizaey/build/meson-logs/meson-log.txt
      + meson setup --prefix=/Library/Frameworks/Python.framework/Versions/3.10 /private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd /private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd/.mesonpy-dadizaey/build --native-file=/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd/.mesonpy-native-file.ini -Ddebug=false -Doptimization=2
      Traceback (most recent call last):
        File "/Users/arun/Applications/venv/pyg/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 156, in prepare_metadata_for_build_wheel
          hook = backend.prepare_metadata_for_build_wheel
      AttributeError: module 'mesonpy' has no attribute 'prepare_metadata_for_build_wheel'
      
      During handling of the above exception, another exception occurred:
      
      Traceback (most recent call last):
        File "/Users/arun/Applications/venv/pyg/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 363, in <module>
          main()
        File "/Users/arun/Applications/venv/pyg/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 345, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
        File "/Users/arun/Applications/venv/pyg/lib/python3.10/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 160, in prepare_metadata_for_build_wheel
          whl_basename = backend.build_wheel(metadata_directory, config_settings)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 1060, in build_wheel
          with _project(config_settings) as project:
        File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/contextlib.py", line 135, in __enter__
          return next(self.gen)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 975, in _project
          with Project.with_temp_working_dir(
        File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/contextlib.py", line 135, in __enter__
          return next(self.gen)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 750, in with_temp_working_dir
          yield cls(source_dir, tmpdir, build_dir, meson_args)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 632, in __init__
          self._configure(reconfigure=bool(build_dir) and not native_file_mismatch)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 680, in _configure
          self._meson('setup', *setup_args)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 657, in _meson
          return self._proc('meson', *args)
        File "/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-build-env-avqqs2yt/overlay/lib/python3.10/site-packages/mesonpy/__init__.py", line 652, in _proc
          subprocess.check_call(list(args), env=self._env)
        File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/subprocess.py", line 369, in check_call
          raise CalledProcessError(retcode, cmd)
      subprocess.CalledProcessError: Command '['meson', 'setup', '--prefix=/Library/Frameworks/Python.framework/Versions/3.10', '/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd', '/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd/.mesonpy-dadizaey/build', '--native-file=/private/var/folders/jx/dw7vjbkj6c90w0c0nfr4r3mh0000gn/T/pip-install-s8b8amzu/scipy_c50bd3e6f9b04552ad59d6e065a2b0fd/.mesonpy-native-file.ini', '-Ddebug=false', '-Doptimization=2']' returned non-zero exit status 1.
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

[eli-schwartz]

ERROR: Unknown compiler(s): [['gfortran'], ['flang'], ['nvfortran'], ['pgfortran'], ['ifort'], ['ifx'], ['g95']]

And then it lists every compiler it attempted to run. Most have reported "no such file or directory", but gfortran says "permission denied" instead.

[eli-schwartz]

ERROR: Unknown compiler(s): [['gfortran'], ['flang'], ['nvfortran'], ['pgfortran'], ['ifort'], ['ifx'], ['g95']]

You must install a compiler capable of building fortran source code. gfortran does seem to be installed, but it raises a permission denied error?

[arunppsg]

I ran ln -s /usr/local/Cellar/gcc/12.2.0/bin/gfortran /usr/local/bin/gfortran to make a symbolic link for gfortran which fixed the permission denied error. I was able to build scipy following it but running into a couple of different issues not related to meson. Thanks for your help!