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authorNadeem Vawda <nadeem.vawda@gmail.com>2012-02-11 21:54:51 (GMT)
committerNadeem Vawda <nadeem.vawda@gmail.com>2012-02-11 21:54:51 (GMT)
commitd1a107132cf8a500478885fef282a1f945b9a981 (patch)
treec2d5e4d655484f17788f7c0a94acdf1d545e1e02
parentf4bdf4e478adc3f7c0ec54e60bb3359f51058722 (diff)
parent30d94b7aea69440605cc7d65e06ac374c25c74c1 (diff)
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Merge: #13989: Document that GzipFile does not support text mode.
-rw-r--r--Doc/library/gzip.rst8
-rw-r--r--Lib/gzip.py11
-rw-r--r--Misc/NEWS3
3 files changed, 15 insertions, 7 deletions
diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst
index 82c9522..9e57990 100644
--- a/Doc/library/gzip.rst
+++ b/Doc/library/gzip.rst
@@ -44,9 +44,11 @@ The module defines the following items:
The *mode* argument can be any of ``'r'``, ``'rb'``, ``'a'``, ``'ab'``, ``'w'``,
or ``'wb'``, depending on whether the file will be read or written. The default
- is the mode of *fileobj* if discernible; otherwise, the default is ``'rb'``. If
- not given, the 'b' flag will be added to the mode to ensure the file is opened
- in binary mode for cross-platform portability.
+ is the mode of *fileobj* if discernible; otherwise, the default is ``'rb'``.
+
+ Note that the file is always opened in binary mode; text mode is not
+ supported. If you need to read a compressed file in text mode, wrap your
+ :class:`GzipFile` with an :class:`io.TextIOWrapper`.
The *compresslevel* argument is an integer from ``1`` to ``9`` controlling the
level of compression; ``1`` is fastest and produces the least compression, and
diff --git a/Lib/gzip.py b/Lib/gzip.py
index 93dda4e..a5bfb85 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -93,6 +93,9 @@ class GzipFile(io.BufferedIOBase):
"""The GzipFile class simulates most of the methods of a file object with
the exception of the readinto() and truncate() methods.
+ This class only supports opening files in binary mode. If you need to open a
+ compressed file in text mode, wrap your GzipFile with an io.TextIOWrapper.
+
"""
myfileobj = None
@@ -119,8 +122,8 @@ class GzipFile(io.BufferedIOBase):
The mode argument can be any of 'r', 'rb', 'a', 'ab', 'w', or 'wb',
depending on whether the file will be read or written. The default
is the mode of fileobj if discernible; otherwise, the default is 'rb'.
- Be aware that only the 'rb', 'ab', and 'wb' values should be used
- for cross-platform portability.
+ A mode of 'r' is equivalent to one of 'rb', and similarly for 'w' and
+ 'wb', and 'a' and 'ab'.
The compresslevel argument is an integer from 1 to 9 controlling the
level of compression; 1 is fastest and produces the least compression,
@@ -137,8 +140,8 @@ class GzipFile(io.BufferedIOBase):
"""
- # guarantee the file is opened in binary mode on platforms
- # that care about that sort of thing
+ if mode and ('t' in mode or 'U' in mode):
+ raise IOError("Mode " + mode + " not supported")
if mode and 'b' not in mode:
mode += 'b'
if fileobj is None:
diff --git a/Misc/NEWS b/Misc/NEWS
index f16c0b7..ef8d6c6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -466,6 +466,9 @@ Core and Builtins
Library
-------
+- Issue #13989: Document that GzipFile does not support text mode, and give a
+ more helpful error message when opened with an invalid mode string.
+
- Issue #13590: On OS X 10.7 and 10.6 with Xcode 4.2, building
Distutils-based packages with C extension modules may fail because
Apple has removed gcc-4.2, the version used to build python.org