python · ambv · May 21, 2025 · May 13, 2025 · May 13, 2025 · May 15, 2025
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):

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 +1,2 @@
+Raise ValueError if an opener returns a negative fd in ``_pyio``
+:func:`open` to match ``_io``
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Raise ValueError if an opener returns a negative fd in ``_pyio``
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		:func:`open` to match ``_io``