bytearray.__mod__() truncates on first \x00

[sanjioh]

BPO	29073
Nosy	@vstinner, @freakboy3742, @ethanfurman, @serhiy-storchaka, @sanjioh
Files	bytearray_format_nul.patch

^{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 2016-12-28.07:59:58.083>
created_at = <Date 2016-12-26.09:52:44.464>
labels = ['interpreter-core', 'type-bug']
title = 'bytearray.__mod__() truncates on first \\x00'
updated_at = <Date 2016-12-28.07:59:58.082>
user = 'https://github.com/sanjioh'

bugs.python.org fields:

activity = <Date 2016-12-28.07:59:58.082>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2016-12-28.07:59:58.083>
closer = 'serhiy.storchaka'
components = ['Interpreter Core']
creation = <Date 2016-12-26.09:52:44.464>
creator = 'sanjioh'
dependencies = []
files = ['46039']
hgrepos = []
issue_num = 29073
keywords = ['patch']
message_count = 4.0
messages = ['284018', '284020', '284021', '284160']
nosy_count = 6.0
nosy_names = ['vstinner', 'freakboy3742', 'ethan.furman', 'python-dev', 'serhiy.storchaka', 'sanjioh']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue29073'
versions = ['Python 3.5']

[sanjioh]

Originally posted by Russell Keith-Magee on Twitter:
https://twitter.com/freakboy3742/status/812609675283681280

Reproduced successfully on Python 3.5.2

>>> x = bytearray(1)
>>> y = {}
>>> x % y
Python3.5: bytearray(b'')
Python3.6: bytearray(b'\x00')

also:
>>> bytearray([0,1]) % {} # same with [], (), range(42)
bytearray(b'')
>>> bytearray([1,0]) % {}
bytearray(b'\x01')

[freakboy3742]

Since I was named dropped; it's worth pointing out that this has evidently been fixed - intentionally or otherwise - in 3.6.

It wasn't an issue in 3.4 and earlier because __mod__ wasn't implemented for bytestrings.

[serhiy-storchaka]

Indeed, there is an inconsistency between bytes and bytearray in 3.5:

>>> b'a\0b' % ()
b'a\x00b'
>>> bytearray(b'a\0b') % ()
bytearray(b'a')

It was unintentionally fixed in bpo-25399.

Proposed patch fixes the issue.

[python-dev]

New changeset 277b36596a54 by Serhiy Storchaka in branch '3.5':
Issue bpo-29073: bytearray formatting no longer truncates on first null byte.
https://hg.python.org/cpython/rev/277b36596a54

New changeset 9b77e3a586b0 by Serhiy Storchaka in branch '3.6':
Issue bpo-29073: Added a test for bytearray formatting with null byte.
https://hg.python.org/cpython/rev/9b77e3a586b0

New changeset 82bfdf599e24 by Serhiy Storchaka in branch 'default':
Issue bpo-29073: Added a test for bytearray formatting with null byte.
https://hg.python.org/cpython/rev/82bfdf599e24