[3.13] gh-71253: Match _io exception in _pyio (gh-133985) (gh-134431)

miss-islington · cmaloney · ZeroIntensity · web-flow · commit 046125e5b6a0 · 2025-05-21T17:14:00.000+02:00
Test was only testing _io, expanded to cover _pyio. (cherry picked from commit 06eaf40) Co-authored-by: Cody Maloney <cmaloney@users.noreply.github.com> Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
@@ -1559,7 +1559,8 @@ def __init__(self, file, mode='r', closefd=True, opener=None):
                     if not isinstance(fd, int):
                         raise TypeError('expected integer from opener')
                     if fd < 0:
-                        raise OSError('Negative file descriptor')
+                        # bpo-27066: Raise a ValueError for bad value.
+                        raise ValueError(f'opener returned {fd}')
                 owned_fd = fd
                 if not noinherit_flag:
                     os.set_inheritable(fd, False)
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
@@ -894,15 +894,15 @@ def test_bad_opener_negative_1(self):
         def badopener(fname, flags):
             return -1
         with self.assertRaises(ValueError) as cm:
-            open('non-existent', 'r', opener=badopener)
+            self.open('non-existent', 'r', opener=badopener)
         self.assertEqual(str(cm.exception), 'opener returned -1')
 
     def test_bad_opener_other_negative(self):
         # Issue #27066.
         def badopener(fname, flags):
             return -2
         with self.assertRaises(ValueError) as cm:
-            open('non-existent', 'r', opener=badopener)
+            self.open('non-existent', 'r', opener=badopener)
         self.assertEqual(str(cm.exception), 'opener returned -2')
 
     def test_opener_invalid_fd(self):
diff --git a/Misc/NEWS.d/next/Library/2025-05-13-18-21-59.gh-issue-71253.-3Sf_K.rst b/Misc/NEWS.d/next/Library/2025-05-13-18-21-59.gh-issue-71253.-3Sf_K.rst
@@ -0,0 +1,3 @@
+Raise :exc:`ValueError` in :func:`open` if *opener* returns a negative
+file-descriptor in the Python implementation of :mod:`io` to match the
+C implementation.
