Include characters_written in BlockingReader

python · gpshead · May 21, 2025 · Feb 27, 2025 · Feb 27, 2025 · Feb 27, 2025
commit 8ea45f3ab08147b8faf66dedd21e2bc7c3404915
diff --git a/Doc/library/io.rst b/Doc/library/io.rst
@@ -823,8 +823,8 @@ than raw I/O does.

      Write the :term:`bytes-like object`, *b*, and return the
      number of bytes written.  When in non-blocking mode, a
-      :exc:`BlockingIOError` is raised if the buffer needs to be written out but
-      the raw stream blocks.
+      :exc:`BlockingIOError` with :attr:`BlockingIOError.characters_written` set
 def test_write_non_blocking(self): 
     raw = self.MockNonBlockWriterIO() 
     bufio = self.tp(raw, 8) 
     self.assertEqual(bufio.write(b"abcd"), 4) 
     self.assertEqual(bufio.write(b"efghi"), 5) 
     # 1 byte will be written, the rest will be buffered 
     raw.block_on(b"k") 
     self.assertEqual(bufio.write(b"jklmn"), 5) 
     # 8 bytes will be written, 8 will be buffered and the rest will be lost 
     raw.block_on(b"0") 
     try: 
         bufio.write(b"opqrwxyz0123456789") 
     except self.BlockingIOError as e: 
         written = e.characters_written 
     else: 
         self.fail("BlockingIOError should have been raised") 
     self.assertEqual(written, 16) 
     self.assertEqual(raw.pop_written(), 
         b"abcdefghijklmnopqrwxyz") 
     self.assertEqual(bufio.write(b"ABCDEFGHI"), 9) 
     s = raw.pop_written() 
     # Previously buffered bytes were flushed 
     self.assertTrue(s.startswith(b"01234567A"), s) 
 def test_write_non_blocking(self): 
     raw = self.MockNonBlockWriterIO() 
     bufio = self.tp(raw, 8) 
  
     self.assertEqual(bufio.write(b"abcd"), 4) 
     self.assertEqual(bufio.write(b"efghi"), 5) 
     # 1 byte will be written, the rest will be buffered 
     raw.block_on(b"k") 
     self.assertEqual(bufio.write(b"jklmn"), 5) 
  
     # 8 bytes will be written, 8 will be buffered and the rest will be lost 
     raw.block_on(b"0") 
     try: 
         bufio.write(b"opqrwxyz0123456789") 
     except self.BlockingIOError as e: 
         written = e.characters_written 
     else: 
         self.fail("BlockingIOError should have been raised") 
     self.assertEqual(written, 16) 
     self.assertEqual(raw.pop_written(), 
         b"abcdefghijklmnopqrwxyz") 
  
     self.assertEqual(bufio.write(b"ABCDEFGHI"), 9) 
     s = raw.pop_written() 
     # Previously buffered bytes were flushed 
     self.assertTrue(s.startswith(b"01234567A"), s) 
+      is raised if the buffer needs to be written out but the raw stream blocks.


 .. class:: BufferedRandom(raw, buffer_size=DEFAULT_BUFFER_SIZE)