bpo-39357: Remove buffering parameter of bz2.BZ2File (GH-18028)
Remove the buffering parameter of bz2.BZ2File. Since Python 3.0, it
was ignored and using it was emitting a DeprecationWarning. Pass an
open file object to control how the file is opened.
The compresslevel parameter becomes keyword-only.
diff --git a/Doc/library/bz2.rst b/Doc/library/bz2.rst
index aa836af..85cdc16 100644
--- a/Doc/library/bz2.rst
+++ b/Doc/library/bz2.rst
@@ -65,7 +65,7 @@
Accepts a :term:`path-like object`.
-.. class:: BZ2File(filename, mode='r', buffering=None, compresslevel=9)
+.. class:: BZ2File(filename, mode='r', *, compresslevel=9)
Open a bzip2-compressed file in binary mode.
@@ -81,8 +81,6 @@
If *filename* is a file object (rather than an actual file name), a mode of
``'w'`` does not truncate the file, and is instead equivalent to ``'a'``.
- The *buffering* argument is ignored. Its use is deprecated since Python 3.0.
-
If *mode* is ``'w'`` or ``'a'``, *compresslevel* can be an integer between
``1`` and ``9`` specifying the level of compression: ``1`` produces the
least compression, and ``9`` (default) produces the most compression.
@@ -110,9 +108,6 @@
.. versionadded:: 3.3
- .. deprecated:: 3.0
- The keyword argument *buffering* was deprecated and is now ignored.
-
.. versionchanged:: 3.1
Support for the :keyword:`with` statement was added.
@@ -138,6 +133,13 @@
.. versionchanged:: 3.6
Accepts a :term:`path-like object`.
+ .. versionchanged:: 3.9
+ The *buffering* parameter has been removed. It was ignored and deprecated
+ since Python 3.0. Pass an open file object to control how the file is
+ opened.
+
+ The *compresslevel* parameter became keyword-only.
+
Incremental (de)compression
---------------------------
diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst
index 8ca7556..f40685c 100644
--- a/Doc/whatsnew/3.9.rst
+++ b/Doc/whatsnew/3.9.rst
@@ -420,6 +420,12 @@
3.5 (:issue:`22486`): use :func:`math.gcd` instead.
(Contributed by Victor Stinner in :issue:`39350`.)
+* The *buffering* parameter of :class:`bz2.BZ2File` has been removed. Since
+ Python 3.0, it was ignored and using it was emitting
+ :exc:`DeprecationWarning`. Pass an open file object to control how the file
+ is opened.
+ (Contributed by Victor Stinner in :issue:`39357`.)
+
Porting to Python 3.9
=====================
@@ -451,6 +457,10 @@
:data:`~errno.EBADF` error.
(Contributed by Victor Stinner in :issue:`39239`.)
+* The *compresslevel* parameter of :class:`bz2.BZ2File` became keyword-only,
+ since the *buffering* parameter has been removed.
+ (Contributed by Victor Stinner in :issue:`39357`.)
+
CPython bytecode changes
------------------------
diff --git a/Lib/bz2.py b/Lib/bz2.py
index 21e8ff4..a499ca3 100644
--- a/Lib/bz2.py
+++ b/Lib/bz2.py
@@ -24,8 +24,6 @@
# Value 2 no longer used
_MODE_WRITE = 3
-_sentinel = object()
-
class BZ2File(_compression.BaseStream):
@@ -38,7 +36,7 @@
returned as bytes, and data to be written should be given as bytes.
"""
- def __init__(self, filename, mode="r", buffering=_sentinel, compresslevel=9):
+ def __init__(self, filename, mode="r", *, compresslevel=9):
"""Open a bzip2-compressed file.
If filename is a str, bytes, or PathLike object, it gives the
@@ -65,12 +63,6 @@
self._closefp = False
self._mode = _MODE_CLOSED
- if buffering is not _sentinel:
- warnings.warn("Use of 'buffering' argument is deprecated and ignored "
- "since Python 3.0.",
- DeprecationWarning,
- stacklevel=2)
-
if not (1 <= compresslevel <= 9):
raise ValueError("compresslevel must be between 1 and 9")
diff --git a/Lib/test/test_bz2.py b/Lib/test/test_bz2.py
index eb2f72e..030d564 100644
--- a/Lib/test/test_bz2.py
+++ b/Lib/test/test_bz2.py
@@ -100,6 +100,9 @@
self.assertRaises(ValueError, BZ2File, os.devnull, compresslevel=0)
self.assertRaises(ValueError, BZ2File, os.devnull, compresslevel=10)
+ # compresslevel is keyword-only
+ self.assertRaises(TypeError, BZ2File, os.devnull, "r", 3)
+
def testRead(self):
self.createTempFile()
with BZ2File(self.filename) as bz2f:
diff --git a/Misc/NEWS.d/next/Library/2020-01-16-11-24-00.bpo-39357.bCwx-h.rst b/Misc/NEWS.d/next/Library/2020-01-16-11-24-00.bpo-39357.bCwx-h.rst
new file mode 100644
index 0000000..a90802c
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-01-16-11-24-00.bpo-39357.bCwx-h.rst
@@ -0,0 +1,4 @@
+Remove the *buffering* parameter of :class:`bz2.BZ2File`. Since Python 3.0, it
+was ignored and using it was emitting :exc:`DeprecationWarning`. Pass an open
+file object, to control how the file is opened. The *compresslevel* parameter
+becomes keyword-only.