Implement realpath for Windows

Author: zooba

Modules/getpath.c

@@ -502,6 +502,45 @@ getpath_realpath(PyObject *Py_UNUSED(self) , PyObject *args)
     PyMem_Free((void *)path);
     PyMem_Free((void *)narrow);
     return r;
+#elif defined(MS_WINDOWS)
+    HANDLE hFile;
+    wchar_t resolved[MAXPATHLEN+1];
+    int len = 0, err;
+    PyObject *result;
+
+    wchar_t *path = PyUnicode_AsWideCharString(pathobj, NULL);
+    if (!path) {
+        return NULL;
+    }
+
+    Py_BEGIN_ALLOW_THREADS
+    hFile = CreateFileW(path, 0, 0, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+    if (hFile != INVALID_HANDLE_VALUE) {
+        len = GetFinalPathNameByHandleW(hFile, resolved, MAXPATHLEN, VOLUME_NAME_DOS);
+        err = len ? 0 : GetLastError();
+        CloseHandle(hFile);
+    } else {
+        err = GetLastError();
+    }
+    Py_END_ALLOW_THREADS
+
+    if (err) {
+        return PyErr_SetFromWindowsErr(GetLastError());
+    }
+    if (len <= MAXPATHLEN) {
+        const wchar_t *p = resolved;
+        if (0 == wcsncmp(p, L"\\\\?\\", 4)) {
+            if (GetFileAttributesW(&p[4]) != INVALID_FILE_ATTRIBUTES) {
+                p += 4;
+                len -= 4;
+            }
+        }
+        result = PyUnicode_FromWideChar(p, len);
+    } else {
+        result = Py_NewRef(pathobj);
+    }
+    PyMem_Free(path);
+    return result;
 #endif
 
     return Py_NewRef(pathobj);
@@ -898,7 +937,7 @@ _PyConfig_InitPathConfig(PyConfig *config, int compute_path_config)
         !library_to_dict(dict, "library") ||
         !wchar_to_dict(dict, "executable_dir", NULL) ||
         !wchar_to_dict(dict, "py_setpath", _PyPathConfig_GetGlobalModuleSearchPath()) ||
-        !funcs_to_dict(dict, 1) || //config->pathconfig_warnings) ||
+        !funcs_to_dict(dict, config->pathconfig_warnings) ||
 #ifndef MS_WINDOWS
         PyDict_SetItemString(dict, "winreg", Py_None) < 0 ||
 #endif

Modules/getpath.py

@@ -358,7 +358,6 @@ def search_up(prefix, *landmarks, test=isfile):
         venv_prefix = None
         pyvenvcfg = []
 
-    warn(f"{base_executable=} {venv_prefix=}")
     for line in pyvenvcfg:
         key, had_equ, value = line.partition('=')
         if had_equ and key.strip().lower() == 'home':
@@ -368,7 +367,6 @@ def search_up(prefix, *landmarks, test=isfile):
                 # more accurate than assuming the executable in 'home'.
                 try:
                     base_executable = realpath(executable)
-                    warn(f"{base_executable=} {executable=}")
                     if base_executable == executable:
                         # No change, so probably not a link. Clear it and fall back
                         base_executable = ''