[issue46681] gzip.compress does not forward compresslevel to zlib.compress

[Ilya Leoshkevich]

New submission from Ilya Leoshkevich <iii at linux.ibm.com>:

Started with:

commit ea23e7820f02840368569db8082bd0ca4d59b62a
Author: Ruben Vorderman <r.h.p.vorderman at lumc.nl>
Date:   Thu Sep 2 17:02:59 2021 +0200

    bpo-43613: Faster implementation of gzip.compress and gzip.decompress (GH-27941)
    
    Co-authored-by: Łukasz Langa <lukasz at langa.pl>

The fix is quite trivial:

--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -587,7 +587,8 @@ def compress(data, compresslevel=_COMPRESS_LEVEL_BEST, *, mtime=None):
     header = _create_simple_gzip_header(compresslevel, mtime)
     trailer = struct.pack("<LL", zlib.crc32(data), (len(data) & 0xffffffff))
     # Wbits=-15 creates a raw deflate block.
-    return header + zlib.compress(data, wbits=-15) + trailer
+    return (header + zlib.compress(data, level=compresslevel, wbits=-15) +
+            trailer)

I'll send a PR.

----------
components: Library (Lib)
messages: 412843
nosy: iii-i
priority: normal
severity: normal
status: open
title: gzip.compress does not forward compresslevel to zlib.compress
type: behavior
versions: Python 3.11

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue46681>
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