diff options
| -rw-r--r-- | Doc/library/io.rst | 20 | ||||
| -rw-r--r-- | Doc/whatsnew/3.14.rst | 9 | ||||
| -rw-r--r-- | Lib/_pyio.py | 5 | ||||
| -rw-r--r-- | Lib/test/test_io.py | 16 | ||||
| -rw-r--r-- | Misc/ACKS | 1 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/C_API/2024-08-12-10-15-19.gh-issue-109523.S2c3fi.rst | 1 | ||||
| -rw-r--r-- | Modules/_io/textio.c | 6 |
7 files changed, 57 insertions, 1 deletions
diff --git a/Doc/library/io.rst b/Doc/library/io.rst index f793d7a..0d8cc51 100644 --- a/Doc/library/io.rst +++ b/Doc/library/io.rst @@ -64,6 +64,12 @@ In-memory text streams are also available as :class:`StringIO` objects:: f = io.StringIO("some initial text data") +.. note:: + + When working with a non-blocking stream, be aware that read operations on text I/O objects + might raise a :exc:`BlockingIOError` if the stream cannot perform the operation + immediately. + The text stream API is described in detail in the documentation of :class:`TextIOBase`. @@ -770,6 +776,11 @@ than raw I/O does. Read and return *size* bytes, or if *size* is not given or negative, until EOF or if the read call would block in non-blocking mode. + .. note:: + + When the underlying raw stream is non-blocking, a :exc:`BlockingIOError` + may be raised if a read operation cannot be completed immediately. + .. method:: read1(size=-1, /) Read and return up to *size* bytes with only one call on the raw stream. @@ -779,6 +790,10 @@ than raw I/O does. .. versionchanged:: 3.7 The *size* argument is now optional. + .. note:: + + When the underlying raw stream is non-blocking, a :exc:`BlockingIOError` + may be raised if a read operation cannot be completed immediately. .. class:: BufferedWriter(raw, buffer_size=DEFAULT_BUFFER_SIZE) @@ -1007,6 +1022,11 @@ Text I/O .. versionchanged:: 3.10 The *encoding* argument now supports the ``"locale"`` dummy encoding name. + .. note:: + + When the underlying raw stream is non-blocking, a :exc:`BlockingIOError` + may be raised if a read operation cannot be completed immediately. + :class:`TextIOWrapper` provides these data attributes and methods in addition to those from :class:`TextIOBase` and :class:`IOBase`: diff --git a/Doc/whatsnew/3.14.rst b/Doc/whatsnew/3.14.rst index f9322da..75d027d 100644 --- a/Doc/whatsnew/3.14.rst +++ b/Doc/whatsnew/3.14.rst @@ -404,6 +404,15 @@ inspect (Contributed by Zhikang Yan in :gh:`125634`.) + +io +-- + +* Reading text from a non-blocking stream with ``read`` may now raise a + :exc:`BlockingIOError` if the operation cannot immediately return bytes. + (Contributed by Giovanni Siragusa in :gh:`109523`.) + + json ---- diff --git a/Lib/_pyio.py b/Lib/_pyio.py index 42b0aea..14961c3 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -2545,9 +2545,12 @@ class TextIOWrapper(TextIOBase): size = size_index() decoder = self._decoder or self._get_decoder() if size < 0: + chunk = self.buffer.read() + if chunk is None: + raise BlockingIOError("Read returned None.") # Read everything. result = (self._get_decoded_chars() + - decoder.decode(self.buffer.read(), final=True)) + decoder.decode(chunk, final=True)) if self._snapshot is not None: self._set_decoded_chars('') self._snapshot = None diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py index f1f8ce5..81c17b2 100644 --- a/Lib/test/test_io.py +++ b/Lib/test/test_io.py @@ -3932,6 +3932,22 @@ class TextIOWrapperTest(unittest.TestCase): f.write(res) self.assertEqual(res + f.readline(), 'foo\nbar\n') + @unittest.skipUnless(hasattr(os, "pipe"), "requires os.pipe()") + def test_read_non_blocking(self): + import os + r, w = os.pipe() + try: + os.set_blocking(r, False) + with self.io.open(r, 'rt') as textfile: + r = None + # Nothing has been written so a non-blocking read raises a BlockingIOError exception. + with self.assertRaises(BlockingIOError): + textfile.read() + finally: + if r is not None: + os.close(r) + os.close(w) + class MemviewBytesIO(io.BytesIO): '''A BytesIO object whose read method returns memoryviews @@ -1736,6 +1736,7 @@ Ng Pheng Siong Yann Sionneau George Sipe J. Sipprell +Giovanni Siragusa Ngalim Siregar Kragen Sitaker Kaartic Sivaraam diff --git a/Misc/NEWS.d/next/C_API/2024-08-12-10-15-19.gh-issue-109523.S2c3fi.rst b/Misc/NEWS.d/next/C_API/2024-08-12-10-15-19.gh-issue-109523.S2c3fi.rst new file mode 100644 index 0000000..9d6b2e0 --- /dev/null +++ b/Misc/NEWS.d/next/C_API/2024-08-12-10-15-19.gh-issue-109523.S2c3fi.rst @@ -0,0 +1 @@ +Reading text from a non-blocking stream with ``read`` may now raise a :exc:`BlockingIOError` if the operation cannot immediately return bytes. diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c index 0d851ee..791ee07 100644 --- a/Modules/_io/textio.c +++ b/Modules/_io/textio.c @@ -1992,6 +1992,12 @@ _io_TextIOWrapper_read_impl(textio *self, Py_ssize_t n) if (bytes == NULL) goto fail; + if (bytes == Py_None){ + Py_DECREF(bytes); + PyErr_SetString(PyExc_BlockingIOError, "Read returned None."); + return NULL; + } + _PyIO_State *state = self->state; if (Py_IS_TYPE(self->decoder, state->PyIncrementalNewlineDecoder_Type)) decoded = _PyIncrementalNewlineDecoder_decode(self->decoder, |