https://github.com/python/cpython/commit/40ce1248866cafd86e062ada66cdc1588b179846 commit: 40ce1248866cafd86e062ada66cdc1588b179846 branch: 3.12 author: Miss Islington (bot) <[email protected]> committer: gpshead <[email protected]> date: 2024-06-17T05:54:33Z summary:
[3.12] gh-112346: Document the OS byte in `gzip.compress` output change in 3.11 (GH-120480) (#120613) 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 <[email protected]> files: M Doc/library/gzip.rst M Doc/whatsnew/3.11.rst diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst index a2fff0f9fcb3e5..3008866671608a 100644 --- a/Doc/library/gzip.rst +++ b/Doc/library/gzip.rst @@ -194,7 +194,9 @@ The module defines the following items: .. versionchanged:: 3.11 Speed is improved by compressing all data at once instead of in a streamed fashion. Calls with *mtime* set to ``0`` are delegated to - :func:`zlib.compress` for better speed. + :func:`zlib.compress` for better speed. In this situation the + output may contain a gzip header "OS" byte value other than 255 + "unknown" as supplied by the underlying zlib implementation. .. function:: decompress(data) diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst index 5e272478ce83ee..cbd5bb23b89254 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 _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: [email protected]
