# HG changeset patch # Parent 4e84e45e191b3b063387fdd68075f47f4576e215 # Parent 97cd199944c3f6b40e9d43c0698b9bb419d81197 Issue #22854: Clarify documentation and test for UnsupportedOperation Also change BufferedReader.writable() and BufferedWriter.readable() to always return False. diff -r 97cd199944c3 Doc/library/io.rst --- a/Doc/library/io.rst Thu Mar 17 15:02:53 2016 -0700 +++ b/Doc/library/io.rst Fri Mar 18 01:41:40 2016 +0000 @@ -265,8 +265,8 @@ .. method:: fileno() Return the underlying file descriptor (an integer) of the stream if it - exists. An :exc:`OSError` is raised if the IO object does not use a file - descriptor. + exists. :exc:`UnsupportedOperation` is raised if the IO object + does not use a file descriptor. .. method:: flush() @@ -281,7 +281,7 @@ .. method:: readable() Return ``True`` if the stream can be read from. If ``False``, :meth:`read` - will raise :exc:`OSError`. + will raise :exc:`UnsupportedOperation`. .. method:: readline(size=-1) @@ -348,7 +348,8 @@ .. method:: writable() Return ``True`` if the stream supports writing. If ``False``, - :meth:`write` and :meth:`truncate` will raise :exc:`OSError`. + :meth:`write` and :meth:`truncate` will raise + :exc:`UnsupportedOperation`. .. method:: writelines(lines) diff -r 97cd199944c3 Lib/_pyio.py --- a/Lib/_pyio.py Thu Mar 17 15:02:53 2016 -0700 +++ b/Lib/_pyio.py Fri Mar 18 01:41:40 2016 +0000 @@ -390,7 +390,7 @@ def seekable(self): """Return a bool indicating whether object supports random access. - If False, seek(), tell() and truncate() will raise UnsupportedOperation. + If False, seek(), tell() and truncate() will raise OSError. This method may need to do a test seek(). """ return False @@ -463,7 +463,8 @@ def fileno(self): """Returns underlying file descriptor (an int) if one exists. - An OSError is raised if the IO object does not use a file descriptor. + UnsupportedOperation is raised if the IO object does not use a file + descriptor. """ self._unsupported("fileno") @@ -787,12 +788,6 @@ def seekable(self): return self.raw.seekable() - def readable(self): - return self.raw.readable() - - def writable(self): - return self.raw.writable() - @property def raw(self): return self._raw @@ -982,6 +977,9 @@ self._reset_read_buf() self._read_lock = Lock() + def readable(self): + return self.raw.readable() + def _reset_read_buf(self): self._read_buf = b"" self._read_pos = 0 @@ -1170,6 +1168,9 @@ self._write_buf = bytearray() self._write_lock = Lock() + def writable(self): + return self.raw.writable() + def write(self, b): if self.closed: raise ValueError("write to closed file") diff -r 97cd199944c3 Lib/test/test_io.py --- a/Lib/test/test_io.py Thu Mar 17 15:02:53 2016 -0700 +++ b/Lib/test/test_io.py Fri Mar 18 01:41:40 2016 +0000 @@ -203,6 +203,9 @@ def tell(self, *args): raise self.UnsupportedOperation("not seekable") + def truncate(self, *args): + raise self.UnsupportedOperation("not seekable") + class CMockUnseekableIO(MockUnseekableIO, io.BytesIO): UnsupportedOperation = io.UnsupportedOperation @@ -361,6 +364,101 @@ self.assertRaises(exc, fp.seek, 1, self.SEEK_CUR) self.assertRaises(exc, fp.seek, -1, self.SEEK_END) + def test_optional_abilities(self): + # Test for UnsupportedOperation when optional APIs are not supported + + def pipe_reader(): + [r, w] = os.pipe() + os.close(w) # So that read() is harmless + return self.FileIO(r, "r") + + def pipe_writer(): + [r, w] = os.pipe() + # Rely on the OS holding one byte in a buffer without blocking, + # so do not close the read end yet + self.addCleanup(os.close, r) + return self.FileIO(w, "w") + + def buffered_reader(): + return self.BufferedReader(self.MockUnseekableIO()) + + def buffered_writer(): + return self.BufferedWriter(self.MockUnseekableIO()) + + def buffered_random(): + return self.BufferedRandom(self.BytesIO()) + + def buffered_rw_pair(): + return self.BufferedRWPair(self.MockUnseekableIO(), + self.MockUnseekableIO()) + + def text_reader(): + class UnseekableReader(self.MockUnseekableIO): + writable = self.BufferedIOBase.writable + write = self.BufferedIOBase.write + return self.TextIOWrapper(UnseekableReader(), "ascii") + + def text_writer(): + class UnseekableWriter(self.MockUnseekableIO): + readable = self.BufferedIOBase.readable + read = self.BufferedIOBase.read + return self.TextIOWrapper(UnseekableWriter(), "ascii") + + tests = ( + (pipe_reader, "fr"), (pipe_writer, "fw"), + (buffered_reader, "r"), (buffered_writer, "w"), + (buffered_random, "rws"), (buffered_rw_pair, "rw"), + (text_reader, "r"), (text_writer, "w"), + (self.BytesIO, "rws"), (self.StringIO, "rws"), + ) + for [test, abilities] in tests: + with self.subTest(test), test() as obj: + readable = "r" in abilities + self.assertEqual(obj.readable(), readable) + writable = "w" in abilities + self.assertEqual(obj.writable(), writable) + seekable = "s" in abilities + self.assertEqual(obj.seekable(), seekable) + + if isinstance(obj, self.TextIOBase): + data = "3" + elif isinstance(obj, (self.BufferedIOBase, self.RawIOBase)): + data = b"3" + else: + self.fail("Unknown base class") + + if "f" in abilities: + obj.fileno() + else: + self.assertRaises(self.UnsupportedOperation, obj.fileno) + + if readable: + obj.read(1) + obj.read() + else: + self.assertRaises(self.UnsupportedOperation, obj.read, 1) + self.assertRaises(self.UnsupportedOperation, obj.read) + + if writable: + obj.write(data) + else: + self.assertRaises(self.UnsupportedOperation, + obj.write, data) + + if seekable: + obj.tell() + obj.seek(0) + else: + self.assertRaises(OSError, obj.tell) + self.assertRaises(OSError, obj.seek, 0) + + if writable and seekable: + obj.truncate() + obj.truncate(0) + else: + self.assertRaises(OSError, obj.truncate) + self.assertRaises(OSError, obj.truncate, 0) + def test_open_handles_NUL_chars(self): fn_with_NUL = 'foo\0bar' self.assertRaises(ValueError, self.open, fn_with_NUL, 'w') @@ -780,13 +878,9 @@ super().flush() rawio = self.MockRawIO() bufio = MyBufferedIO(rawio) - writable = bufio.writable() del bufio support.gc_collect() - if writable: - self.assertEqual(record, [1, 2, 3]) - else: - self.assertEqual(record, [1, 2]) + self.assertEqual(record, [1, 2, 3]) def test_context_manager(self): # Test usability as a context manager diff -r 97cd199944c3 Misc/NEWS --- a/Misc/NEWS Thu Mar 17 15:02:53 2016 -0700 +++ b/Misc/NEWS Fri Mar 18 01:41:40 2016 +0000 @@ -226,6 +226,9 @@ Library ------- +- Issue #22854: Change BufferedReader.writable() and + BufferedWriter.readable() to always return False. + - Issue #26313: ssl.py _load_windows_store_certs fails if windows cert store is empty. Patch by Baji. diff -r 97cd199944c3 Modules/_io/bufferedio.c --- a/Modules/_io/bufferedio.c Thu Mar 17 15:02:53 2016 -0700 +++ b/Modules/_io/bufferedio.c Fri Mar 18 01:41:40 2016 +0000 @@ -2398,7 +2398,6 @@ {"close", (PyCFunction)buffered_close, METH_NOARGS}, {"seekable", (PyCFunction)buffered_seekable, METH_NOARGS}, {"readable", (PyCFunction)buffered_readable, METH_NOARGS}, - {"writable", (PyCFunction)buffered_writable, METH_NOARGS}, {"fileno", (PyCFunction)buffered_fileno, METH_NOARGS}, {"isatty", (PyCFunction)buffered_isatty, METH_NOARGS}, {"_dealloc_warn", (PyCFunction)buffered_dealloc_warn, METH_O}, @@ -2489,7 +2488,6 @@ {"close", (PyCFunction)buffered_close, METH_NOARGS}, {"detach", (PyCFunction)buffered_detach, METH_NOARGS}, {"seekable", (PyCFunction)buffered_seekable, METH_NOARGS}, - {"readable", (PyCFunction)buffered_readable, METH_NOARGS}, {"writable", (PyCFunction)buffered_writable, METH_NOARGS}, {"fileno", (PyCFunction)buffered_fileno, METH_NOARGS}, {"isatty", (PyCFunction)buffered_isatty, METH_NOARGS}, diff -r 97cd199944c3 Modules/_io/clinic/iobase.c.h --- a/Modules/_io/clinic/iobase.c.h Thu Mar 17 15:02:53 2016 -0700 +++ b/Modules/_io/clinic/iobase.c.h Fri Mar 18 01:41:40 2016 +0000 @@ -66,7 +66,7 @@ "\n" "Return whether object supports random access.\n" "\n" -"If False, seek(), tell() and truncate() will raise UnsupportedOperation.\n" +"If False, seek(), tell() and truncate() will raise OSError.\n" "This method may need to do a test seek()."); #define _IO__IOBASE_SEEKABLE_METHODDEF \ @@ -127,7 +127,8 @@ "\n" "Returns underlying file descriptor if one exists.\n" "\n" -"An IOError is raised if the IO object does not use a file descriptor."); +"UnsupportedOperation is raised if the IO object does not use a file\n" +"descriptor."); #define _IO__IOBASE_FILENO_METHODDEF \ {"fileno", (PyCFunction)_io__IOBase_fileno, METH_NOARGS, _io__IOBase_fileno__doc__}, @@ -276,4 +277,4 @@ { return _io__RawIOBase_readall_impl(self); } -/*[clinic end generated code: output=fe034152b6884e65 input=a9049054013a1b77]*/ +/*[clinic end generated code: output=4d33148a58e083d2 input=a9049054013a1b77]*/ diff -r 97cd199944c3 Modules/_io/iobase.c --- a/Modules/_io/iobase.c Thu Mar 17 15:02:53 2016 -0700 +++ b/Modules/_io/iobase.c Fri Mar 18 01:41:40 2016 +0000 @@ -335,13 +335,13 @@ Return whether object supports random access. -If False, seek(), tell() and truncate() will raise UnsupportedOperation. +If False, seek(), tell() and truncate() will raise OSError. This method may need to do a test seek(). [clinic start generated code]*/ static PyObject * _io__IOBase_seekable_impl(PyObject *self) -/*[clinic end generated code: output=4c24c67f5f32a43d input=22676eebb81dcf1e]*/ +/*[clinic end generated code: output=4c24c67f5f32a43d input=b976622f7fdf3063]*/ { Py_RETURN_FALSE; } @@ -456,12 +456,13 @@ Returns underlying file descriptor if one exists. -An IOError is raised if the IO object does not use a file descriptor. +UnsupportedOperation is raised if the IO object does not use a file +descriptor. [clinic start generated code]*/ static PyObject * _io__IOBase_fileno_impl(PyObject *self) -/*[clinic end generated code: output=7cc0973f0f5f3b73 input=32773c5df4b7eede]*/ +/*[clinic end generated code: output=7cc0973f0f5f3b73 input=7ef33b2cd31b92e2]*/ { return iobase_unsupported("fileno"); }