Cannot import extensions linked against `python3_d.dll` debug build on Windows

[davidhewitt]

Bug report

Build a debug version of CPython on Windows.
Build an an extension module linked against this debug CPython's python3_d.dll.

This crashes at runtime with the following error:

ImportError: Module use of python3_d.dll conflicts with this version of Python.

This originates from

cpython/Python/dynload_win.c

Lines 311 to 330 in 7a25310

	PyOS_snprintf(buffer, sizeof(buffer),
	#ifdef _DEBUG
	"python%d%d_d.dll",
	#else
	"python%d%d.dll",
	#endif
	PY_MAJOR_VERSION,PY_MINOR_VERSION);
	import_python = GetPythonImport(hDLL);
	if (import_python &&
	_stricmp(buffer,import_python)) {
	PyErr_Format(PyExc_ImportError,
	"Module use of %.150s conflicts "
	"with this version of Python.",
	import_python);
	Py_BEGIN_ALLOW_THREADS
	FreeLibrary(hDLL);
	Py_END_ALLOW_THREADS
	return NULL;
	}

It looks like this code doesn't account for the possibility of linking against python3_d.dll when using a debug build.

Your environment

• CPython versions tested on: main branch, 7a25310
• Operating system and architecture: Windows 12 amd64

Originally reported to me in PyO3/pyo3#2780

Linked PRs

• gh-101614: don't treat python3_d.dll as a Python dll #101615
• [3.11] gh-101614: Don't treat python3_d.dll as a Python DLL when checking extension modules for incompatibility (GH-101615) #101690
• [3.10] gh-101614: Don't treat python3_d.dll as a Python DLL when checking extension modules for incompatibility (GH-101615) #101691

[hugovk]

Thanks for the fixes!