bpo-38823: Always build _ctypes with wchar_t (GH-23248)

It is no longer possible to build the _ctypes extension module
without wchar_t type: remove CTYPES_UNICODE macro. Anyway, the
wchar_t type is required to build Python.

Misc/NEWS.d/next/Build/2020-11-12-13-45-15.bpo-38823.C0z_Fe.rst

@@ -0,0 +1,3 @@
+It is no longer possible to build the ``_ctypes`` extension module without
+:c:type:`wchar_t` type: remove ``CTYPES_UNICODE`` macro. Anyway, the
+:c:type:`wchar_t` type is required to build Python. Patch by Victor Stinner.

Modules/_ctypes/_ctypes.c

@@ -1358,7 +1358,6 @@ static PyGetSetDef CharArray_getsets[] = {
     { NULL, NULL }
 };
 
-#ifdef CTYPES_UNICODE
 static PyObject *
 WCharArray_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 {
@@ -1408,7 +1407,6 @@ static PyGetSetDef WCharArray_getsets[] = {
       "string value"},
     { NULL, NULL }
 };
-#endif
 
 /*
   The next three functions copied from Python's typeobject.c.
@@ -1615,11 +1613,10 @@ PyCArrayType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     if (itemdict->getfunc == _ctypes_get_fielddesc("c")->getfunc) {
         if (-1 == add_getset(result, CharArray_getsets))
             goto error;
-#ifdef CTYPES_UNICODE
-    } else if (itemdict->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
+    }
+    else if (itemdict->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
         if (-1 == add_getset(result, WCharArray_getsets))
             goto error;
-#endif
     }
 
     return (PyObject *)result;
@@ -4654,7 +4651,6 @@ Array_subscript(PyObject *myself, PyObject *item)
             PyMem_Free(dest);
             return np;
         }
-#ifdef CTYPES_UNICODE
         if (itemdict->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
             wchar_t *ptr = (wchar_t *)self->b_ptr;
             wchar_t *dest;
@@ -4681,7 +4677,6 @@ Array_subscript(PyObject *myself, PyObject *item)
             PyMem_Free(dest);
             return np;
         }
-#endif
 
         np = PyList_New(slicelen);
         if (np == NULL)
@@ -5350,7 +5345,6 @@ Pointer_subscript(PyObject *myself, PyObject *item)
             PyMem_Free(dest);
             return np;
         }
-#ifdef CTYPES_UNICODE
         if (itemdict->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
             wchar_t *ptr = *(wchar_t **)self->b_ptr;
             wchar_t *dest;
@@ -5371,7 +5365,6 @@ Pointer_subscript(PyObject *myself, PyObject *item)
             PyMem_Free(dest);
             return np;
         }
-#endif
 
         np = PyList_New(len);
         if (np == NULL)
@@ -5653,7 +5646,7 @@ cast(void *ptr, PyObject *src, PyObject *ctype)
     return NULL;
 }
 
-#ifdef CTYPES_UNICODE
+
 static PyObject *
 wstring_at(const wchar_t *ptr, int size)
 {
@@ -5665,7 +5658,6 @@ wstring_at(const wchar_t *ptr, int size)
         ssize = wcslen(ptr);
     return PyUnicode_FromWideChar(ptr, ssize);
 }
-#endif
 
 
 static struct PyModuleDef _ctypesmodule = {
@@ -5796,9 +5788,7 @@ _ctypes_add_objects(PyObject *mod)
     MOD_ADD("_memset_addr", PyLong_FromVoidPtr(memset));
     MOD_ADD("_string_at_addr", PyLong_FromVoidPtr(string_at));
     MOD_ADD("_cast_addr", PyLong_FromVoidPtr(cast));
-#ifdef CTYPES_UNICODE
     MOD_ADD("_wstring_at_addr", PyLong_FromVoidPtr(wstring_at));
-#endif
 
 /* If RTLD_LOCAL is not defined (Windows!), set it to zero. */
 #if !HAVE_DECL_RTLD_LOCAL

Modules/_ctypes/callproc.c

@@ -713,7 +713,6 @@ static int ConvParam(PyObject *obj, Py_ssize_t index, struct argument *pa)
         return 0;
     }
 
-#ifdef CTYPES_UNICODE
     if (PyUnicode_Check(obj)) {
         pa->ffi_type = &ffi_type_pointer;
         pa->value.p = PyUnicode_AsWideCharString(obj, NULL);
@@ -726,7 +725,6 @@ static int ConvParam(PyObject *obj, Py_ssize_t index, struct argument *pa)
         }
         return 0;
     }
-#endif
 
     {
         _Py_IDENTIFIER(_as_parameter_);

Modules/_ctypes/cfield.c

@@ -125,13 +125,11 @@ PyCField_FromDesc(PyObject *desc, Py_ssize_t index,
                 getfunc = fd->getfunc;
                 setfunc = fd->setfunc;
             }
-#ifdef CTYPES_UNICODE
             if (idict->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
                 struct fielddesc *fd = _ctypes_get_fielddesc("U");
                 getfunc = fd->getfunc;
                 setfunc = fd->setfunc;
             }
-#endif
         }
     }
 
@@ -1137,7 +1135,6 @@ c_get(void *ptr, Py_ssize_t size)
     return PyBytes_FromStringAndSize((char *)ptr, 1);
 }
 
-#ifdef CTYPES_UNICODE
 /* u - a single wchar_t character */
 static PyObject *
 u_set(void *ptr, PyObject *value, Py_ssize_t size)
@@ -1232,7 +1229,6 @@ U_set(void *ptr, PyObject *value, Py_ssize_t length)
     return value;
 }
 
-#endif
 
 static PyObject *
 s_get(void *ptr, Py_ssize_t size)
@@ -1321,7 +1317,6 @@ z_get(void *ptr, Py_ssize_t size)
     }
 }
 
-#ifdef CTYPES_UNICODE
 static PyObject *
 Z_set(void *ptr, PyObject *value, Py_ssize_t size)
 {
@@ -1373,7 +1368,7 @@ Z_get(void *ptr, Py_ssize_t size)
         Py_RETURN_NONE;
     }
 }
-#endif
+
 
 #ifdef MS_WIN32
 static PyObject *
@@ -1507,11 +1502,9 @@ static struct fielddesc formattable[] = {
 #endif
     { 'P', P_set, P_get, &ffi_type_pointer},
     { 'z', z_set, z_get, &ffi_type_pointer},
-#ifdef CTYPES_UNICODE
     { 'u', u_set, u_get, NULL}, /* ffi_type set later */
     { 'U', U_set, U_get, &ffi_type_pointer},
     { 'Z', Z_set, Z_get, &ffi_type_pointer},
-#endif
 #ifdef MS_WIN32
     { 'X', BSTR_set, BSTR_get, &ffi_type_pointer},
 #endif
@@ -1544,14 +1537,12 @@ _ctypes_get_fielddesc(const char *fmt)
 
     if (!initialized) {
         initialized = 1;
-#ifdef CTYPES_UNICODE
         if (sizeof(wchar_t) == sizeof(short))
             _ctypes_get_fielddesc("u")->pffi_type = &ffi_type_sshort;
         else if (sizeof(wchar_t) == sizeof(int))
             _ctypes_get_fielddesc("u")->pffi_type = &ffi_type_sint;
         else if (sizeof(wchar_t) == sizeof(long))
             _ctypes_get_fielddesc("u")->pffi_type = &ffi_type_slong;
-#endif
     }
 
     for (; table->code; ++table) {

Modules/_ctypes/ctypes.h

@@ -343,10 +343,6 @@ extern PyObject *PyExc_ArgError;
 extern char *_ctypes_conversion_encoding;
 extern char *_ctypes_conversion_errors;
 
-#if defined(HAVE_WCHAR_H)
-#  define CTYPES_UNICODE
-#endif
-
 
 extern void _ctypes_free_closure(void *);
 extern void *_ctypes_alloc_closure(void);

Modules/_ctypes/stgdict.c

@@ -538,9 +538,7 @@ PyCStructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct
             case FFI_TYPE_SINT16:
             case FFI_TYPE_SINT32:
                 if (dict->getfunc != _ctypes_get_fielddesc("c")->getfunc
-#ifdef CTYPES_UNICODE
                     && dict->getfunc != _ctypes_get_fielddesc("u")->getfunc
-#endif
                     )
                     break;
                 /* else fall through */