ValueError: too many values to unpack

[qris]

pdm.exceptions.BuildError: Build backend raised error: Showing the last 10 lines of the build output:
    ffibuilder.compile(verbose=True)
  File "/tmp/pdm-build-env-ot45gqlp-overlay/lib/python3.10/site-packages/cffi/api.py", line 727, in compile
    return recompile(self, module_name, source, tmpdir=tmpdir,
  File "/tmp/pdm-build-env-ot45gqlp-overlay/lib/python3.10/site-packages/cffi/recompiler.py", line 1581, in recompile
    outputfilename = ffiplatform.compile('.', ext,
  File "/tmp/pdm-build-env-ot45gqlp-overlay/lib/python3.10/site-packages/cffi/ffiplatform.py", line 20, in compile
    outputfilename = _build(tmpdir, ext, compiler_verbose, debug)
  File "/tmp/pdm-build-env-ot45gqlp-overlay/lib/python3.10/site-packages/cffi/ffiplatform.py", line 50, in _build
    [soname] = cmd_obj.get_outputs()
ValueError: too many values to unpack (expected 1)

I know there's probably something wrong with my build, but this isn't supposed to happen, and probably makes it harder to debug.

This is CFFI 2.0.0.

[mattip]

What would you suggest to get a nicer error output? Maybe a check that cmd_obj.get_outputs() is not empty?

[qris]

@mattip sorry, I have no idea what causes get_outputs() to be empty. I'm a complete beginner with CFFI and this error message leaves me lost. If I misconfigured CFFI somehow then it would be good to know in what way (and ideally how to fix it, or at least a pointer). If some command produced no output, then what command was it?