gh-108512: Add and use new replacements for PySys_GetObject()

Add functions PySys_GetAttr() and PySys_GetAttrString().

Author: serhiy-storchaka

Doc/c-api/init_config.rst

@@ -2098,7 +2098,7 @@ initialization::
 
         /* Specify sys.path explicitly */
         /* If you want to modify the default set of paths, finish
-           initialization first and then use PySys_GetObject("path") */
+           initialization first and then use PySys_GetAttrString("path", ...) */
         config.module_search_paths_set = 1;
         status = PyWideStringList_Append(&config.module_search_paths,
                                          L"/path/to/stdlib");

Doc/c-api/sys.rst

@@ -258,11 +258,36 @@ These are utility functions that make functionality from the :mod:`sys` module
 accessible to C code.  They all work with the current interpreter thread's
 :mod:`sys` module's dict, which is contained in the internal thread state structure.
 
+.. c:function:: int PySys_GetAttr(PyObject *name, PyObject **result);
+
+   Get the attribute *name* of the :mod:`sys` module.
+
+   If the object exists, set *\*result* to a new :term:`strong reference`
+   to the object and return ``1``.
+   If the object does not exist, set *\*result* to ``NULL`` and return ``0``,
+   without setting an exception.
+   If other error occurred, set an exception, set *\*result* to ``NULL`` and
+   return ``-1``.
+
+   .. versionadded:: next
+
+.. c:function:: int PySys_GetAttrString(const char *name, PyObject **result);
+
+   This is the same as :c:func:`PySys_GetAttr`, but *name* is
+   specified as a :c:expr:`const char*` UTF-8 encoded bytes string,
+   rather than a :c:expr:`PyObject*`.
+
+   .. versionadded:: next
+
 .. c:function:: PyObject *PySys_GetObject(const char *name)
 
    Return the object *name* from the :mod:`sys` module or ``NULL`` if it does
    not exist, without setting an exception.
 
+   Preserves exception that was set before the call.
+
+   It is recommended to use :c:func:`PySys_GetAttrString` instead.
+
 .. c:function:: int PySys_SetObject(const char *name, PyObject *v)
 
    Set *name* in the :mod:`sys` module to *v* unless *v* is ``NULL``, in which

Doc/data/stable_abi.dat

@@ -1296,6 +1296,10 @@ New features
 
   (Contributed by Sergey B Kirpichev and Victor Stinner in :gh:`102471`.)
 
+* Add :c:func:`PySys_GetAttr` and :c:func:`PySys_GetAttrString`
+  functions as replacements for :c:func:`PySys_GetObject`.
+  (Contributed by Serhiy Storchaka in :gh:`108512`.)
+
 * Add :c:func:`PyType_GetBaseByToken` and :c:data:`Py_tp_token` slot for easier
   superclass identification, which attempts to resolve the `type checking issue
   <https://peps.python.org/pep-0630/#type-checking>`__ mentioned in :pep:`630`

Doc/whatsnew/3.14.rst

@@ -0,0 +1,23 @@
+#ifndef Py_CPYTHON_SYSMODULE_H
+#  error "this header file must not be included directly"
+#endif
+
+typedef int(*Py_AuditHookFunction)(const char *, PyObject *, void *);
+
+PyAPI_FUNC(int) PySys_Audit(
+    const char *event,
+    const char *format,
+    ...);
+PyAPI_FUNC(int) PySys_AddAuditHook(Py_AuditHookFunction, void*);
+
+typedef struct {
+    FILE* perf_map;
+    PyThread_type_lock map_lock;
+} PerfMapState;
+
+PyAPI_FUNC(int) PyUnstable_PerfMapState_Init(void);
+PyAPI_FUNC(int) PyUnstable_WritePerfMapEntry(
+    const void *code_addr,
+    unsigned int code_size,
+    const char *entry_name);
+PyAPI_FUNC(void) PyUnstable_PerfMapState_Fini(void);

Include/cpython/sysmodule.h

@@ -8,8 +8,8 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
-// Export for '_pickle' shared extension
-PyAPI_FUNC(PyObject*) _PySys_GetAttr(PyThreadState *tstate, PyObject *name);
+PyAPI_FUNC(PyObject *) _PySys_GetRequiredAttr(PyObject *);
+PyAPI_FUNC(PyObject *) _PySys_GetRequiredAttrString(const char *);
 
 // Export for '_pickle' shared extension
 PyAPI_FUNC(size_t) _PySys_GetSizeOf(PyObject *);

Include/internal/pycore_sysmodule.h

@@ -4,6 +4,10 @@
 extern "C" {
 #endif
 
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030e0000
+PyAPI_FUNC(int) PySys_GetAttr(PyObject *, PyObject **);
+PyAPI_FUNC(int) PySys_GetAttrString(const char *, PyObject **);
+#endif
 PyAPI_FUNC(PyObject *) PySys_GetObject(const char *);
 PyAPI_FUNC(int) PySys_SetObject(const char *, PyObject *);
 

Include/sysmodule.h

@@ -9,6 +9,11 @@
 except ImportError:
     _testlimitedcapi = None
 
+try:
+    import _testinternalcapi
+except ImportError:
+    _testinternalcapi = None
+
 NULL = None
 
 class CAPITest(unittest.TestCase):
@@ -19,6 +24,33 @@ class CAPITest(unittest.TestCase):
 
     maxDiff = None
 
+    @unittest.skipIf(_testlimitedcapi is None, 'need _testlimitedcapi module')
+    def test_sys_getattr(self):
+        # Test PySys_GetAttr()
+        sys_getattr = _testlimitedcapi.sys_getattr
+
+        self.assertIs(sys_getattr('stdout'), sys.stdout)
+        with support.swap_attr(sys, '\U0001f40d', 42):
+            self.assertEqual(sys_getattr('\U0001f40d'), 42)
+
+        self.assertIs(sys_getattr('nonexisting'), AttributeError)
+        self.assertRaises(TypeError, sys_getattr, 1)
+        self.assertRaises(TypeError, sys_getattr, [])
+        # CRASHES sys_getattr(NULL)
+
+    @unittest.skipIf(_testlimitedcapi is None, 'need _testlimitedcapi module')
+    def test_sys_getattrstring(self):
+        # Test PySys_GetAttrString()
+        getattrstring = _testlimitedcapi.sys_getattrstring
+
+        self.assertIs(getattrstring(b'stdout'), sys.stdout)
+        with support.swap_attr(sys, '\U0001f40d', 42):
+            self.assertEqual(getattrstring('\U0001f40d'.encode()), 42)
+
+        self.assertIs(getattrstring(b'nonexisting'), AttributeError)
+        self.assertRaises(UnicodeDecodeError, getattrstring, b'\xff')
+        # CRASHES getattrstring(NULL)
+
     @support.cpython_only
     @unittest.skipIf(_testlimitedcapi is None, 'need _testlimitedcapi module')
     def test_sys_getobject(self):

Lib/test/test_capi/test_sys.py

@@ -0,0 +1 @@
+Add functions :c:func:`PySys_GetAttr` and :c:func:`PySys_GetAttrString`.