uu-codec trailing garbage workaround is Python 2 code

[vadmium]

BPO	22406
Nosy	@malemburg, @doerwalter, @vadmium, @serhiy-storchaka
Files	test.patch: Test uu_codec.patch: Fix

^{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/serhiy-storchaka'
closed_at = <Date 2014-11-07.12:56:21.744>
created_at = <Date 2014-09-14.13:46:54.340>
labels = ['easy', 'type-bug', 'library']
title = 'uu-codec trailing garbage workaround is Python 2 code'
updated_at = <Date 2014-11-07.12:56:21.743>
user = 'https://github.com/vadmium'

bugs.python.org fields:

activity = <Date 2014-11-07.12:56:21.743>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2014-11-07.12:56:21.744>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2014-09-14.13:46:54.340>
creator = 'martin.panter'
dependencies = []
files = ['36618', '36619']
hgrepos = []
issue_num = 22406
keywords = ['easy']
message_count = 5.0
messages = ['226870', '226877', '226898', '230800', '230803']
nosy_count = 5.0
nosy_names = ['lemburg', 'doerwalter', 'python-dev', 'martin.panter', 'serhiy.storchaka']
pr_nums = []
priority = 'low'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue22406'
versions = ['Python 3.4', 'Python 3.5']

[vadmium]

The handler for the “Trailing garbage” error for “uu-codec” uses Python 2 code, while the copy in the "uu” module has the correct Python 3 code.

Please change the line at

https://hg.python.org/cpython/file/775453a7b85d/Lib/encodings/uu_codec.py#l57

to look like

https://hg.python.org/cpython/file/775453a7b85d/Lib/uu.py#l148

In particular, drop ord() and use floor division. Better yet, maybe the code could be reused so that there is less duplication!

Demonstration:

>>> codecs.decode(b"begin 666 <data>\n!,___\n \nend\n", "uu-codec")
Traceback (most recent call last):
  File "/usr/lib/python3.4/encodings/uu_codec.py", line 54, in uu_decode
    data = binascii.a2b_uu(s)
binascii.Error: Trailing garbage

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.4/encodings/uu_codec.py", line 57, in uu_decode
    nbytes = (((ord(s[0])-32) & 63) * 4 + 5) / 3
TypeError: ord() expected string of length 1, but int found

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: decoding with 'uu-codec' codec failed (TypeError: ord() expected string of length 1, but int found)
>>> codecs.decode(b"begin 666 <data>\n!,P  \n \nend\n", "uu-codec")
b'3'  # Expected output for both cases

[serhiy-storchaka]

Do you want to provide a patch Martin?

[vadmium]

Here are two patches: a test and a fix. I’m not sure if it is okay to add a test for the “codecs” module with the tests for the “uu” module; it was easier that way because I am basically running the same test over the two different APIs.

[python-dev]

New changeset ad89a652b4ed by Serhiy Storchaka in branch '3.4':
Issue bpo-22406: Fixed the uu_codec codec incorrectly ported to 3.x.
https://hg.python.org/cpython/rev/ad89a652b4ed

New changeset b18ef4a3e7c1 by Serhiy Storchaka in branch 'default':
Issue bpo-22406: Fixed the uu_codec codec incorrectly ported to 3.x.
https://hg.python.org/cpython/rev/b18ef4a3e7c1

New changeset 7b82b58b8329 by Serhiy Storchaka in branch '2.7':
Backported tests for issue bpo-22406.
https://hg.python.org/cpython/rev/7b82b58b8329

[serhiy-storchaka]

I think it is safer now just fix existing code than replace it with totally different code with the risk of incompatibility. In any case uu_codec needs rewriting because currently it doesn't support incremental encoding and decoding.

Thank you for your contribution Martin. And if you are going to do further contribution, please submit a contributor form (https://www.python.org/psf/contrib/).

Few notes. It is more handy to provide all changes as one patch. And your patches contain trailing spaces in blank lines.