gh-127350: Add Py_fopen() function

Doc/c-api/sys.rst

@@ -218,16 +218,17 @@ Operating System Utilities
 
 .. c:function:: FILE* Py_fopen(PyObject *path, const char *mode)
 
-   Similar to the :c:func:`!fopen` function, but *path* is a Python object and
+   Similar to :c:func:`!fopen`, but *path* is a Python object and
    an exception is set on error.
 
-   *path* must be a :class:`str` object or a :class:`bytes` object.
+   *path* must be a :class:`str` object, a :class:`bytes` object,
+   or a :term:`path-like object`.
 
-   On success, return the new file object.
+   On success, return the new file pointer.
    On error, set an exception and return ``NULL``.
 
    The file must be closed by :c:func:`Py_fclose` rather than calling directly
-   ``fclose()``.
+   :c:func:`!fclose`.
 
    The file descriptor is created non-inheritable (:pep:`446`).
 
@@ -238,7 +239,7 @@ Operating System Utilities
 
 .. c:function:: int Py_fclose(FILE *file)
 
-   Closes files that were opened by :c:func:`Py_fopen`.
+   Close a file that was opened by :c:func:`Py_fopen`.
 
    On success, return ``0``.
    On error, return ``EOF`` and ``errno`` is set to indicate the error.

Doc/whatsnew/3.14.rst

@@ -1227,12 +1227,23 @@ New features
 * Add :c:func:`PyUnstable_Object_EnableDeferredRefcount` for enabling
   deferred reference counting, as outlined in :pep:`703`.
 
+* The :ref:`Unicode Exception Objects <unicodeexceptions>` C API
+  now raises a :exc:`TypeError` if its exception argument is not
+  a :exc:`UnicodeError` object.
+  (Contributed by Bénédikt Tran in :gh:`127691`.)
+
+* Add :c:func:`PyMonitoring_FireBranchLeftEvent` and
+  :c:func:`PyMonitoring_FireBranchRightEvent` for generating
+  :monitoring-event:`BRANCH_LEFT` and :monitoring-event:`BRANCH_RIGHT`
+  events, respectively.
+
 * Add :c:func:`Py_fopen` function to open a file. Similar to the
   :c:func:`!fopen` function, but the *path* parameter is a Python object and an
   exception is set on error. Add also :c:func:`Py_fclose` function to close a
   file.
   (Contributed by Victor Stinner in :gh:`127350`.)
 
+
 Porting to Python 3.14
 ----------------------
 

Include/cpython/fileutils.h

@@ -6,4 +6,9 @@ PyAPI_FUNC(FILE*) Py_fopen(
     PyObject *path,
     const char *mode);
 
+// Deprecated alias to Py_fopen() kept for backward compatibility
+Py_DEPRECATED(3.14) PyAPI_FUNC(FILE*) _Py_fopen_obj(
+    PyObject *path,
+    const char *mode);
+
 PyAPI_FUNC(int) Py_fclose(FILE *file);

Lib/test/test_capi/test_file.py

@@ -1,22 +1,67 @@
 import os
 import unittest
-from test.support import import_helper
+from test import support
+from test.support import import_helper, os_helper
 
 _testcapi = import_helper.import_module('_testcapi')
 
 
 class CAPIFileTest(unittest.TestCase):
     def test_py_fopen(self):
+        # Test Py_fopen() and Py_fclose()
+        class FSPath:
+            def __init__(self, path):
+                self.path = path
+            def __fspath__(self):
+                return self.path
+
+        with open(__file__, "rb") as fp:
+            source = fp.read()
+
         for filename in (__file__, os.fsencode(__file__)):
             with self.subTest(filename=filename):
-                content = _testcapi.py_fopen(filename, "rb")
-                with open(filename, "rb") as fp:
-                    self.assertEqual(fp.read(256), content)
+                data = _testcapi.py_fopen(filename, "rb")
+                self.assertEqual(data, source[:256])
+
+                data = _testcapi.py_fopen(FSPath(filename), "rb")
+                self.assertEqual(data, source[:256])
+
+        for filename in (
+            os_helper.TESTFN,
+            os.fsencode(os_helper.TESTFN),
+            os_helper.TESTFN_UNDECODABLE,
+            os_helper.TESTFN_UNENCODABLE,
+        ):
+            with self.subTest(filename=filename):
+                try:
+                    with open(filename, "wb") as fp:
+                        fp.write(source)
 
+                    data = _testcapi.py_fopen(filename, "rb")
+                    self.assertEqual(data, source[:256])
+                finally:
+                    os_helper.unlink(filename)
+
+        # embedded null character/byte in the filename
+        with self.assertRaises(ValueError):
+            _testcapi.py_fopen("a\x00b", "rb")
+        with self.assertRaises(ValueError):
+            _testcapi.py_fopen(b"a\x00b", "rb")
+
+        # non-ASCII mode failing with "Invalid argument"
+        with self.assertRaises(OSError):
+            _testcapi.py_fopen(__file__, "\xe9")
+
+        # invalid filename type
         for invalid_type in (123, object()):
             with self.subTest(filename=invalid_type):
                 with self.assertRaises(TypeError):
-                    _testcapi.py_fopen(invalid_type, "r")
+                    _testcapi.py_fopen(invalid_type, "rb")
+
+        if support.MS_WINDOWS:
+            with self.assertRaises(OSError):
+                # On Windows, the file mode is limited to 10 characters
+                _testcapi.py_fopen(__file__, "rt+, ccs=UTF-8")
 
 
 if __name__ == "__main__":

Python/fileutils.c

@@ -1776,6 +1776,12 @@ Py_fopen(PyObject *path, const char *mode)
     int async_err = 0;
     int saved_errno;
 #ifdef MS_WINDOWS
+    PyObject *fspath = PyOS_FSPath(path);
+    if (fspath == NULL) {
+        return NULL;
+    }
+    Py_SETREF(path, fspath);
+
     if (PyUnicode_Check(path)) {
         wchar_t *wpath = PyUnicode_AsWideCharString(path, NULL);
         if (wpath == NULL) {
@@ -1837,6 +1843,14 @@ Py_fopen(PyObject *path, const char *mode)
 }
 
 
+// Deprecated alias to Py_fopen() kept for backward compatibility
+FILE*
+_Py_fopen_obj(PyObject *path, const char *mode)
+{
+    return Py_fopen(path, mode);
+}
+
+
 // Call fclose().
 //
 // On Windows, files opened by Py_fopen() in the Python DLL must be closed by