diff --git a/Lib/_pyio.py b/Lib/_pyio.py index 37157d53ab4..a467ddda4ff 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -390,7 +390,7 @@ class IOBase(metaclass=abc.ABCMeta): 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 @@ -405,7 +405,7 @@ class IOBase(metaclass=abc.ABCMeta): def readable(self): """Return a bool indicating whether object was opened for reading. - If False, read() will raise UnsupportedOperation. + If False, read() will raise OSError. """ return False @@ -419,7 +419,7 @@ class IOBase(metaclass=abc.ABCMeta): def writable(self): """Return a bool indicating whether object was opened for writing. - If False, write() and truncate() will raise UnsupportedOperation. + If False, write() and truncate() will raise OSError. """ return False @@ -787,12 +787,6 @@ class _BufferedIOMixin(BufferedIOBase): 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 +976,9 @@ class BufferedReader(_BufferedIOMixin): 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 +1167,9 @@ class BufferedWriter(_BufferedIOMixin): 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 --git a/Lib/test/test_io.py b/Lib/test/test_io.py index 86440c5b39b..51c250b40b2 100644 --- a/Lib/test/test_io.py +++ b/Lib/test/test_io.py @@ -203,6 +203,9 @@ class MockUnseekableIO: 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 +364,107 @@ class IOTest(unittest.TestCase): 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 OSError when optional APIs are not supported + # The purpose of this test is to try fileno(), reading, writing and + # seeking operations with various objects that indicate they do not + # support these operations. + + 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() + self.addCleanup(os.close, r) + # Guarantee that we can write into the pipe without blocking + thread = threading.Thread(target=os.read, args=(r, 100)) + thread.start() + self.addCleanup(thread.join) + 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: + if test is pipe_writer and not threading: + continue # Skip subtest that uses a background thread + 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(OSError, obj.fileno) + + if readable: + obj.read(1) + obj.read() + else: + self.assertRaises(OSError, obj.read, 1) + self.assertRaises(OSError, obj.read) + + if writable: + obj.write(data) + else: + self.assertRaises(OSError, 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') @@ -747,12 +851,6 @@ class CommonBufferedTests: self.assertEqual(42, bufio.fileno()) - @unittest.skip('test having existential crisis') - def test_no_fileno(self): - # XXX will we always have fileno() function? If so, kill - # this test. Else, write it. - pass - def test_invalid_args(self): rawio = self.MockRawIO() bufio = self.tp(rawio) @@ -780,13 +878,9 @@ class CommonBufferedTests: 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 --git a/Misc/NEWS b/Misc/NEWS index 391bbf256e6..e2e37a4064a 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -99,6 +99,9 @@ Core and Builtins Library ------- +- Issue #22854: Change BufferedReader.writable() and + BufferedWriter.readable() to always return False. + - Issue #25195: Fix a regression in mock.MagicMock. _Call is a subclass of tuple (changeset 3603bae63c13 only works for classes) so we need to implement __ne__ ourselves. Patch by Andrew Plummer. diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c index ae4af9d5ffd..f751446991a 100644 --- a/Modules/_io/bufferedio.c +++ b/Modules/_io/bufferedio.c @@ -2398,7 +2398,6 @@ static PyMethodDef bufferedreader_methods[] = { {"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 @@ static PyMethodDef bufferedwriter_methods[] = { {"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 --git a/Modules/_io/clinic/iobase.c.h b/Modules/_io/clinic/iobase.c.h index 3cea079d454..9762f11222d 100644 --- a/Modules/_io/clinic/iobase.c.h +++ b/Modules/_io/clinic/iobase.c.h @@ -66,7 +66,7 @@ PyDoc_STRVAR(_io__IOBase_seekable__doc__, "\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 \ @@ -87,7 +87,7 @@ PyDoc_STRVAR(_io__IOBase_readable__doc__, "\n" "Return whether object was opened for reading.\n" "\n" -"If False, read() will raise UnsupportedOperation."); +"If False, read() will raise OSError."); #define _IO__IOBASE_READABLE_METHODDEF \ {"readable", (PyCFunction)_io__IOBase_readable, METH_NOARGS, _io__IOBase_readable__doc__}, @@ -107,7 +107,7 @@ PyDoc_STRVAR(_io__IOBase_writable__doc__, "\n" "Return whether object was opened for writing.\n" "\n" -"If False, write() will raise UnsupportedOperation."); +"If False, write() will raise OSError."); #define _IO__IOBASE_WRITABLE_METHODDEF \ {"writable", (PyCFunction)_io__IOBase_writable, METH_NOARGS, _io__IOBase_writable__doc__}, @@ -127,7 +127,7 @@ PyDoc_STRVAR(_io__IOBase_fileno__doc__, "\n" "Returns underlying file descriptor if one exists.\n" "\n" -"An IOError is raised if the IO object does not use a file descriptor."); +"OSError is raised if the IO object does not use a file descriptor."); #define _IO__IOBASE_FILENO_METHODDEF \ {"fileno", (PyCFunction)_io__IOBase_fileno, METH_NOARGS, _io__IOBase_fileno__doc__}, @@ -276,4 +276,4 @@ _io__RawIOBase_readall(PyObject *self, PyObject *Py_UNUSED(ignored)) { return _io__RawIOBase_readall_impl(self); } -/*[clinic end generated code: output=fe034152b6884e65 input=a9049054013a1b77]*/ +/*[clinic end generated code: output=b874952f5cc248a4 input=a9049054013a1b77]*/ diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c index 025007e40dc..090891d631a 100644 --- a/Modules/_io/iobase.c +++ b/Modules/_io/iobase.c @@ -335,13 +335,13 @@ _io._IOBase.seekable 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; } @@ -368,12 +368,12 @@ _io._IOBase.readable Return whether object was opened for reading. -If False, read() will raise UnsupportedOperation. +If False, read() will raise OSError. [clinic start generated code]*/ static PyObject * _io__IOBase_readable_impl(PyObject *self) -/*[clinic end generated code: output=e48089250686388b input=12fc3d8f6be46434]*/ +/*[clinic end generated code: output=e48089250686388b input=285b3b866a0ec35f]*/ { Py_RETURN_FALSE; } @@ -401,12 +401,12 @@ _io._IOBase.writable Return whether object was opened for writing. -If False, write() will raise UnsupportedOperation. +If False, write() will raise OSError. [clinic start generated code]*/ static PyObject * _io__IOBase_writable_impl(PyObject *self) -/*[clinic end generated code: output=406001d0985be14f input=c17a0bb6a8dfc590]*/ +/*[clinic end generated code: output=406001d0985be14f input=9dcac18a013a05b5]*/ { Py_RETURN_FALSE; } @@ -456,12 +456,12 @@ _io._IOBase.fileno Returns underlying file descriptor if one exists. -An IOError is raised if the IO object does not use a file descriptor. +OSError 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=4e37028947dc1cc8]*/ { return iobase_unsupported("fileno"); }