str literals, which are not docstrings, should not be allowed between __future__ imports

[Arfrever]

BPO	17434
Nosy	@benjaminp

^{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 = None
closed_at = <Date 2013-03-16.16:27:04.132>
created_at = <Date 2013-03-16.00:13:57.549>
labels = ['interpreter-core']
title = 'str literals, which are not docstrings, should not be allowed between __future__ imports'
updated_at = <Date 2013-03-16.16:28:15.870>
user = 'https://bugs.python.org/Arfrever'

bugs.python.org fields:

activity = <Date 2013-03-16.16:28:15.870>
actor = 'python-dev'
assignee = 'none'
closed = True
closed_date = <Date 2013-03-16.16:27:04.132>
closer = 'benjamin.peterson'
components = ['Interpreter Core']
creation = <Date 2013-03-16.00:13:57.549>
creator = 'Arfrever'
dependencies = []
files = []
hgrepos = []
issue_num = 17434
keywords = []
message_count = 4.0
messages = ['184277', '184287', '184328', '184329']
nosy_count = 3.0
nosy_names = ['benjamin.peterson', 'Arfrever', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue17434'
versions = ['Python 2.7', 'Python 3.2', 'Python 3.3', 'Python 3.4']

[Arfrever]

test1.py shows that a str literal before first import from __future__ is a docstring.
test2.py shows that a str literal after first import from __future__ is not a docstring.
test2.py shows that if docstring is absent, then a single str literal between imports from __future__ does not cause SyntaxError, while it should.
test3.py shows that if docstring is present, then a str literal between imports from __future__ causes SyntaxError.
test4.py shows that if docstring is absent, then >=2 str literals between imports from __future__ cause SyntaxError.

$ cat test1.py
"some text"
from __future__ import absolute_import
print(__doc__)
$ cat test2.py
from __future__ import absolute_import
"some text"
from __future__ import print_function
print(__doc__)
$ cat test3.py
"some text 1"
from __future__ import absolute_import
"some text 2"
from __future__ import print_function
$ cat test4.py
from __future__ import absolute_import
"some text 1"
"some text 2"
from __future__ import print_function
$ python3.4 test1.py
some text
$ python3.4 test2.py
None
$ python3.4 test3.py
  File "test3.py", line 4
    from __future__ import print_function
    ^
SyntaxError: from __future__ imports must occur at the beginning of the file
$ python3.4 test4.py
  File "test4.py", line 4
    from __future__ import print_function
    ^
SyntaxError: from __future__ imports must occur at the beginning of the file
$

[Arfrever]

Jython and PyPy properly raise SyntaxError for test2.py.

[benjaminp]

46cadd3955d0

[python-dev]

New changeset 46cadd3955d0 by Benjamin Peterson in branch 'default':
reject non-docs strings between future imports (closes bpo-17434)
http://hg.python.org/cpython/rev/46cadd3955d0