Fix ternary, doc method ref, move test to just c impl

Author: inventshah

Lib/test/test_io/test_bufferedio.py

@@ -922,14 +922,6 @@ def test_slow_close_from_thread(self):
         self.assertTrue(bufio.closed)
         t.join()
 
-    def test_close_without_closed(self):
-        # gh-140650: check TypeError is raised
-        class MockRawIOWithoutClosed(self.MockRawIO):
-            closed = NotImplemented
-
-        bufio = self.tp(MockRawIOWithoutClosed())
-        self.assertRaises(TypeError, bufio.close)
-
 
 class CBufferedWriterTest(BufferedWriterTest, SizeofTest, CTestCase):
     tp = io.BufferedWriter
@@ -970,6 +962,14 @@ def test_args_error(self):
         with self.assertRaisesRegex(TypeError, "BufferedWriter"):
             self.tp(self.BytesIO(), 1024, 1024, 1024)
 
+    def test_close_without_closed(self):
+        # gh-140650: check TypeError is raised
+        class MockRawIOWithoutClosed(self.MockRawIO):
+            closed = NotImplemented
+
+        bufio = self.tp(MockRawIOWithoutClosed())
+        self.assertRaises(TypeError, bufio.close)
+
 
 class PyBufferedWriterTest(BufferedWriterTest, PyTestCase):
     tp = pyio.BufferedWriter

Misc/NEWS.d/next/Library/2025-10-27-00-40-49.gh-issue-140650.DYJPJ9.rst

@@ -1,2 +1,2 @@
-Fix an issue where :meth:`io.BufferedWriter.close` would crash when "closed"
-was not implemented.
+Fix an issue where closing :class:`io.BufferedWriter` could crash
+if the closed attribute had the wrong type.

Modules/_io/bufferedio.c

@@ -362,7 +362,7 @@ _enter_buffered_busy(buffered *self)
     }
 
 #define IS_CLOSED(self) \
-    (!self->buffer ?: \
+    (!self->buffer ? !self->buffer : \
     (self->fast_closed_checks \
      ? _PyFileIO_closed(self->raw) \
      : buffered_closed(self)))