gh-71253: Match _io exception in _pyio

Test was only testing _io, expanded to cover _pyio.
python · ambv · May 21, 2025 · May 13, 2025 · May 13, 2025 · May 15, 2025
commit 53bea44f358b5a5c9b76e7b52f97c2aa3e93a0e4
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
@@ -1563,7 +1563,8 @@ 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
@@ -918,15 +918,15 @@ 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):