gh-81773: Avoid parsing sys.version string in sysconfig

Lib/sysconfig/__init__.py

@@ -1,5 +1,6 @@
 """Access to Python's configuration information."""
 
+import _sysconfig
 import os
 import sys
 import threading
@@ -172,7 +173,6 @@ def joinuser(*args):
 _SCHEME_KEYS = ('stdlib', 'platstdlib', 'purelib', 'platlib', 'include',
                 'scripts', 'data')
 
-_PY_VERSION = sys.version.split()[0]
 _PY_VERSION_SHORT = f'{sys.version_info[0]}.{sys.version_info[1]}'
 _PY_VERSION_SHORT_NO_DOT = f'{sys.version_info[0]}{sys.version_info[1]}'
 _BASE_PREFIX = os.path.normpath(sys.base_prefix)
@@ -385,14 +385,10 @@ def _init_non_posix(vars):
     """Initialize the module as appropriate for NT"""
     # set basic install directories
     import _winapi
-    import _sysconfig
     vars['LIBDEST'] = get_path('stdlib')
     vars['BINLIBDEST'] = get_path('platstdlib')
     vars['INCLUDEPY'] = get_path('include')
 
-    # Add EXT_SUFFIX, SOABI, Py_DEBUG, and Py_GIL_DISABLED
-    vars.update(_sysconfig.config_vars())
-
     # NOTE: ABIFLAGS is only an emulated value. It is not present during build
     #       on Windows. sys.abiflags is absent on Windows and vars['abiflags']
     #       is already widely used to calculate paths, so it should remain an
@@ -505,6 +501,10 @@ def _init_config_vars():
     global _CONFIG_VARS
     _CONFIG_VARS = {}
 
+    # Add py_version, Py_DEBUG, and Py_GIL_DISABLED.
+    # On Windows, add also EXT_SUFFIX and SOABI.
+    _CONFIG_VARS.update(_sysconfig.config_vars())
+
     prefix = os.path.normpath(sys.prefix)
     exec_prefix = os.path.normpath(sys.exec_prefix)
     base_prefix = _BASE_PREFIX
@@ -530,7 +530,6 @@ def _init_config_vars():
     # Distutils.
     _CONFIG_VARS['prefix'] = prefix
     _CONFIG_VARS['exec_prefix'] = exec_prefix
-    _CONFIG_VARS['py_version'] = _PY_VERSION
     _CONFIG_VARS['py_version_short'] = _PY_VERSION_SHORT
     _CONFIG_VARS['py_version_nodot'] = _PY_VERSION_SHORT_NO_DOT
     _CONFIG_VARS['installed_base'] = base_prefix
@@ -665,7 +664,6 @@ def get_platform():
 
     For other non-POSIX platforms, currently just returns :data:`sys.platform`."""
     if os.name == 'nt':
-        import _sysconfig
         platform = _sysconfig.get_platform()
         if platform:
             return platform

Lib/test/test_sysconfig.py

@@ -741,6 +741,27 @@ def test_sysconfig_config_vars_no_prefix_cache(self):
         self.assertEqual(config_vars['exec_prefix'], sys.exec_prefix)
         self.assertEqual(config_vars['platbase'], sys.exec_prefix)
 
+    def test_py_version(self):
+        # Test py_version
+        config_vars = sysconfig.get_config_vars()
+        self.assertIsInstance(config_vars['py_version'], str)
+        ver = sys.version_info
+        version = f'{ver.major}.{ver.minor}.{ver.micro}'
+        # py_version can be longer such as "3.15.0a7+" instead of "3.15.0"
+        self.assertStartsWith(config_vars['py_version'], version)
+
+        # Test py_version_short and get_python_version()
+        self.assertIsInstance(config_vars['py_version_short'], str)
+        self.assertEqual(config_vars['py_version_short'],
+                         f'{ver.major}.{ver.minor}')
+        self.assertEqual(sysconfig.get_python_version(),
+                         f'{ver.major}.{ver.minor}')
+
+        # Test py_version_nodot
+        self.assertIsInstance(config_vars['py_version_nodot'], str)
+        self.assertEqual(config_vars['py_version_nodot'],
+                         f'{ver.major}{ver.minor}')
+
 
 class MakefileTests(unittest.TestCase):
 

Modules/_sysconfig.c

@@ -17,7 +17,6 @@ module _sysconfig
 
 #include "clinic/_sysconfig.c.h"
 
-#ifdef MS_WINDOWS
 static int
 add_string_value(PyObject *dict, const char *key, const char *str_value)
 {
@@ -29,7 +28,6 @@ add_string_value(PyObject *dict, const char *key, const char *str_value)
     Py_DECREF(value);
     return err;
 }
-#endif
 
 /*[clinic input]
 @permit_long_summary
@@ -47,14 +45,17 @@ _sysconfig_config_vars_impl(PyObject *module)
         return NULL;
     }
 
+    // Python version
+    if (add_string_value(config, "py_version", PY_VERSION) < 0) {
+        goto error;
+    }
+
 #ifdef MS_WINDOWS
     if (add_string_value(config, "EXT_SUFFIX", PYD_TAGGED_SUFFIX) < 0) {
-        Py_DECREF(config);
-        return NULL;
+        goto error;
     }
     if (add_string_value(config, "SOABI", PYD_SOABI) < 0) {
-        Py_DECREF(config);
-        return NULL;
+        goto error;
     }
 #endif
 
@@ -64,8 +65,7 @@ _sysconfig_config_vars_impl(PyObject *module)
     PyObject *py_gil_disabled = _PyLong_GetZero();
 #endif
     if (PyDict_SetItemString(config, "Py_GIL_DISABLED", py_gil_disabled) < 0) {
-        Py_DECREF(config);
-        return NULL;
+        goto error;
     }
 
 #ifdef Py_DEBUG
@@ -74,11 +74,14 @@ _sysconfig_config_vars_impl(PyObject *module)
     PyObject *py_debug = _PyLong_GetZero();
 #endif
     if (PyDict_SetItemString(config, "Py_DEBUG", py_debug) < 0) {
-        Py_DECREF(config);
-        return NULL;
+        goto error;
     }
 
     return config;
+
+error:
+    Py_DECREF(config);
+    return NULL;
 }
 
 #ifdef MS_WINDOWS