getpath: use normpath on all generated paths

Instead of just calling normpath in abspath just call normpath
on all the config results. This makes sure we don't change getpath.py
too much and still cover all outputs.

This fixes sys.exec_prefix not matching sys.prefix, see
#142

Lib/test/test_getpath.py

@@ -914,6 +914,9 @@ def __missing__(self, key):
         except AttributeError:
             raise KeyError(key) from None
 
+    def normpath(self, path):
+        return ntpath.normpath(path)
+
     def abspath(self, path):
         if self.isabs(path):
             return path
@@ -1092,6 +1095,9 @@ def __missing__(self, key):
         except AttributeError:
             raise KeyError(key) from None
 
+    def normpath(self, path):
+        return path
+
     def abspath(self, path):
         if self.isabs(path):
             return path

Modules/getpath.c

@@ -54,6 +54,25 @@
 
 /* HELPER FUNCTIONS for getpath.py */
 
+static PyObject *
+getpath_normpath(PyObject *Py_UNUSED(self), PyObject *args)
+{
+    PyObject *r = NULL;
+    PyObject *pathobj;
+    wchar_t *path;
+    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
+        return NULL;
+    }
+    Py_ssize_t len;
+    wchar_t *buffer = PyUnicode_AsWideCharString(pathobj, &len);
+    if (!buffer) {
+        return NULL;
+    }
+    r = PyUnicode_FromWideChar(_Py_normpath(buffer, len), -1);
+    PyMem_Free(buffer);
+    return r;
+}
+
 static PyObject *
 getpath_abspath(PyObject *Py_UNUSED(self), PyObject *args)
 {
@@ -68,7 +87,6 @@ getpath_abspath(PyObject *Py_UNUSED(self), PyObject *args)
     if (path) {
         wchar_t *abs;
         if (_Py_abspath((const wchar_t *)_Py_normpath(path, -1), &abs) == 0 && abs) {
-            abs = _Py_normpath(abs, -1);
             r = PyUnicode_FromWideChar(abs, -1);
             PyMem_RawFree((void *)abs);
         } else {
@@ -526,6 +544,7 @@ getpath_realpath(PyObject *Py_UNUSED(self) , PyObject *args)
 
 
 static PyMethodDef getpath_methods[] = {
+    {"normpath", getpath_normpath, METH_VARARGS, NULL},
     {"abspath", getpath_abspath, METH_VARARGS, NULL},
     {"basename", getpath_basename, METH_VARARGS, NULL},
     {"dirname", getpath_dirname, METH_VARARGS, NULL},

Modules/getpath.py

@@ -233,6 +233,8 @@ def search_up(prefix, *landmarks, test=isfile):
             return prefix
         prefix = dirname(prefix)
 
+def _normpath(p):
+    return normpath(p) if p is not None else None
 
 # ******************************************************************************
 # READ VARIABLES FROM config
@@ -670,7 +672,7 @@ def search_up(prefix, *landmarks, test=isfile):
 
 if py_setpath:
     # If Py_SetPath was called then it overrides any existing search path
-    config['module_search_paths'] = py_setpath.split(DELIM)
+    config['module_search_paths'] = [_normpath(p) for p in py_setpath.split(DELIM)]
     config['module_search_paths_set'] = 1
 
 elif not pythonpath_was_set:
@@ -757,7 +759,7 @@ def search_up(prefix, *landmarks, test=isfile):
         if platstdlib_dir:
             pythonpath.append(platstdlib_dir)
 
-    config['module_search_paths'] = pythonpath
+    config['module_search_paths'] = [_normpath(p) for p in pythonpath]
     config['module_search_paths_set'] = 1
 
 
@@ -792,23 +794,23 @@ def search_up(prefix, *landmarks, test=isfile):
             warn("unsupported 'import' line in ._pth file")
         else:
             pythonpath.append(joinpath(pth_dir, line))
-    config['module_search_paths'] = pythonpath
+    config['module_search_paths'] = [_normpath(p) for p in pythonpath]
     config['module_search_paths_set'] = 1
 
 # ******************************************************************************
 # UPDATE config FROM CALCULATED VALUES
 # ******************************************************************************
 
-config['program_name'] = program_name
-config['home'] = home
-config['executable'] = executable
-config['base_executable'] = base_executable
-config['prefix'] = prefix
-config['exec_prefix'] = exec_prefix
-config['base_prefix'] = base_prefix or prefix
-config['base_exec_prefix'] = base_exec_prefix or exec_prefix
+config['program_name'] = _normpath(program_name)
+config['home'] = _normpath(home)
+config['executable'] = _normpath(executable)
+config['base_executable'] = _normpath(base_executable)
+config['prefix'] = _normpath(prefix)
+config['exec_prefix'] = _normpath(exec_prefix)
+config['base_prefix'] = _normpath(base_prefix or prefix)
+config['base_exec_prefix'] = _normpath(base_exec_prefix or exec_prefix)
 
-config['platlibdir'] = platlibdir
+config['platlibdir'] = _normpath(platlibdir)
 # test_embed expects empty strings, not None
-config['stdlib_dir'] = stdlib_dir or ''
-config['platstdlib_dir'] = platstdlib_dir or ''
+config['stdlib_dir'] = _normpath(stdlib_dir or '')
+config['platstdlib_dir'] = _normpath(platstdlib_dir or '')