replace `io.IncrementalNewlineDecoder` with non incremental newline decoders

[guoci]

BPO	46186
Nosy	@merwok, @JelleZijlstra, @guoci
PRs	GH-90344: replace io.IncrementalNewlineDecoder with non incremental newline decoders #30276

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

Show more details

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-12-27.18:01:06.947>
labels = ['3.11']
title = 'replace `io.IncrementalNewlineDecoder` with non incremental newline decoders'
updated_at = <Date 2022-01-27.20:45:24.350>
user = 'https://github.com/guoci'

bugs.python.org fields:

activity = <Date 2022-01-27.20:45:24.350>
actor = 'guoci'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2021-12-27.18:01:06.947>
creator = 'guoci'
dependencies = []
files = []
hgrepos = []
issue_num = 46186
keywords = ['patch']
message_count = 6.0
messages = ['409235', '409236', '409475', '409476', '411443', '411922']
nosy_count = 3.0
nosy_names = ['eric.araujo', 'JelleZijlstra', 'guoci']
pr_nums = ['30276']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue46186'
versions = ['Python 3.11']

[guoci]

replace unnecessary use of io.IncrementalNewlineDecoder in code.
Some uses of the decode method were also incorrect without the final=True argument.

[guoci]

In any case, the use of an incremental newline decoder is not required

[merwok]

Can you describe what the problem is?
Is it incorrect in some cases? Is it inefficient?

Without a statement of the issue, we can’t discuss a solution :)

[guoci]

Some uses of the decode method of io.IncrementalNewlineDecoder were incorrect without the final=True argument.
One way to fix it would be to add the final=True in all cases.
But the incremental decoding feature is not used, so I decided to replace it with stateless non-incremental newline decoders.

[JelleZijlstra]

If the old code is incorrect, can you give an example where it fails? Is it possible to write a unit test demonstrating that the current behavior is wrong?

[guoci]

The old code has an incorrect usage of io.IncrementalNewlineDecoder. Since the decode method is called only once, is it the final call and needs the final=True argument as documented in https://docs.python.org/dev/library/codecs.html#codecs.IncrementalDecoder.decode

It happens that in those cases, the results are correct in spite of the incorrect usage.