Fix confusing versionchanged note in crc32 and adler32

[animalize]

BPO	47040
Nosy	@gpshead, @animalize, @miss-islington
PRs	bpo-47040: improve document of checksum functions #31955 [3.10] bpo-47040: improve document of checksum functions (GH-31955) #32002 [3.9] [3.10] bpo-47040: improve document of checksum functions (GH-31955) (GH-32002) #32004

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/gpshead'
closed_at = <Date 2022-03-19.23:08:03.511>
created_at = <Date 2022-03-17.05:35:08.673>
labels = ['3.11', 'library', '3.9', '3.10', 'docs']
title = 'Fix confusing versionchanged note in crc32 and adler32'
updated_at = <Date 2022-03-20.07:21:41.731>
user = 'https://github.com/animalize'

bugs.python.org fields:

activity = <Date 2022-03-20.07:21:41.731>
actor = 'miss-islington'
assignee = 'gregory.p.smith'
closed = True
closed_date = <Date 2022-03-19.23:08:03.511>
closer = 'gregory.p.smith'
components = ['Documentation', 'Library (Lib)']
creation = <Date 2022-03-17.05:35:08.673>
creator = 'malin'
dependencies = []
files = []
hgrepos = []
issue_num = 47040
keywords = ['patch']
message_count = 8.0
messages = ['415386', '415389', '415574', '415582', '415583', '415592', '415594', '415595']
nosy_count = 4.0
nosy_names = ['gregory.p.smith', 'docs@python', 'malin', 'miss-islington']
pr_nums = ['31955', '32002', '32004']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue47040'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

[animalize]

Since CPython 3.0.0, the checksums are always truncated to unsigned int:
https://github.com/python/cpython/blob/v3.0/Modules/zlibmodule.c#L930
https://github.com/python/cpython/blob/v3.0/Modules/zlibmodule.c#L950

[animalize]

binascii.crc32 doc also has this invalid document:
doc: https://docs.python.org/3/library/binascii.html#binascii.crc32
3.0.0 code: https://github.com/python/cpython/blob/v3.0/Modules/binascii.c#L1035

In addition, binascii.crc32 has an USE_ZLIB_CRC32 code path, but it's buggy.
The length of zlib crc32() function is unsigned int, so if use USE_ZLIB_CRC32 code path and the data > 4GiB, the result is wrong.
Should we remove USE_ZLIB_CRC32 code path in binascii.c, or fix it?

USE_ZLIB_CRC32 code path in binascii.c (bug code):
https://github.com/python/cpython/blob/v3.11.0a6/Modules/binascii.c#L756-L767
crc32 in zlibmodule.c, it uses an UINT_MAX sliding window (right code):
https://github.com/python/cpython/blob/v3.11.0a6/Modules/zlibmodule.c#L1436

[gpshead]

New changeset b3f2d4c by Ma Lin in branch 'main':
bpo-47040: improve document of checksum functions (gh-31955)
b3f2d4c

[gpshead]

FYI - https://bugs.python.org/issue38256 covers the 32-bit bug.

[gpshead]

If you want to backport the documentation updates, feel free to make PRs for that.

[animalize]

PR 32002 is for 3.10/3.9 branches.

[gpshead]

New changeset 6d290d5 by Ma Lin in branch '3.10':
[3.10] bpo-47040: improve document of checksum functions (GH-31955) (GH-32002)
6d290d5

[miss-islington]

New changeset 73f4b47 by Miss Islington (bot) in branch '3.9':
[3.10] bpo-47040: improve document of checksum functions (GH-31955) (GH-32002)
73f4b47