bpo-45211: Remember the stdlib dir during startup. (gh-28586)

During runtime startup we figure out the stdlib dir but currently throw that information away. This change preserves it and exposes it via PyConfig.stdlib_dir, _Py_GetStdlibDir(), and sys._stdlib_dir.

https://bugs.python.org/issue45211

1 files changed, 10 insertions, 0 deletions

diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index e98803b48f..3b80904b28 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -13,6 +13,7 @@ from test import support
 from test.support import os_helper
 from test.support.script_helper import assert_python_ok, assert_python_failure
 from test.support import threading_helper
+from test.support import import_helper
 import textwrap
 import unittest
 import warnings
@@ -994,6 +995,15 @@ class SysModuleTest(unittest.TestCase):
         for name in sys.stdlib_module_names:
             self.assertIsInstance(name, str)
 
+    def test_stdlib_dir(self):
+        os = import_helper.import_fresh_module('os')
+        marker = getattr(os, '__file__', None)
+        if marker and not os.path.exists(marker):
+            marker = None
+        expected = os.path.dirname(marker) if marker else None
+        actual = sys._stdlib_dir
+        self.assertEqual(actual, expected)
+
 
 @test.support.cpython_only
 class UnraisableHookTest(unittest.TestCase):