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authorMiss Islington (bot) <31488909+miss-islington@users.noreply.github.com>2024-06-17 06:06:11 (GMT)
committerGitHub <noreply@github.com>2024-06-17 06:06:11 (GMT)
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[3.13] gh-112346: Document the OS byte in `gzip.compress` output change in 3.11 (GH-120480) (#120612)
gh-112346: Document the OS byte in `gzip.compress` output change in 3.11 (GH-120480) (cherry picked from commit bac4edad69bb20dd9460766e062637cae999e1e0) gh-112346: Describe the "os" byte in gzip output change. Co-authored-by: Gregory P. Smith <greg@krypto.org>
Diffstat (limited to 'Doc/whatsnew')
-rw-r--r--Doc/whatsnew/3.11.rst15
1 files changed, 15 insertions, 0 deletions
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
index 7a74df3..b601bd4 100644
--- a/Doc/whatsnew/3.11.rst
+++ b/Doc/whatsnew/3.11.rst
@@ -768,6 +768,21 @@ functools
(Contributed by Yurii Karabas in :issue:`46014`.)
+.. _whatsnew311-gzip:
+
+gzip
+----
+
+* The :func:`gzip.compress` function is now faster when used with the
+ **mtime=0** argument as it delegates the compression entirely to a single
+ :func:`zlib.compress` operation. There is one side effect of this change: The
+ gzip file header contains an "OS" byte in its header. That was traditionally
+ always set to a value of 255 representing "unknown" by the :mod:`gzip`
+ module. Now, when using :func:`~gzip.compress` with **mtime=0**, it may be
+ set to a different value by the underlying zlib C library Python was linked
+ against.
+ (See :gh:`112346` for details on the side effect.)
+
.. _whatsnew311-hashlib:
hashlib