Some Invalid Relative Imports succeed in Py 3.0 & 3.1 [& correctly fail in 3.2rc1]

[mark-summerfield]

BPO	10926
Nosy	@brettcannon, @ncoghlan, @orsenthil, @mark-summerfield
Superseder	bpo-7902: relative import broken
Files	py-import-bug.tar.gz

^{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 2011-01-17.17:01:49.834>
created_at = <Date 2011-01-17.14:28:30.419>
labels = ['interpreter-core', 'type-bug']
title = 'Some Invalid Relative Imports succeed in Py 3.0 & 3.1 [& correctly fail in 3.2rc1]'
updated_at = <Date 2011-01-17.17:01:49.833>
user = 'https://github.com/mark-summerfield'

bugs.python.org fields:

activity = <Date 2011-01-17.17:01:49.833>
actor = 'r.david.murray'
assignee = 'none'
closed = True
closed_date = <Date 2011-01-17.17:01:49.834>
closer = 'r.david.murray'
components = ['Interpreter Core']
creation = <Date 2011-01-17.14:28:30.419>
creator = 'mark'
dependencies = []
files = ['20424']
hgrepos = []
issue_num = 10926
keywords = []
message_count = 3.0
messages = ['126399', '126404', '126409']
nosy_count = 4.0
nosy_names = ['brett.cannon', 'ncoghlan', 'orsenthil', 'mark']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '7902'
type = 'behavior'
url = 'https://bugs.python.org/issue10926'
versions = ['Python 3.1', 'Python 3.2']

[mark-summerfield]

I'm reporting this at Georg Brandl's suggestion.

If you unpack the attached (tiny) tarball you get this directory structure:

Graphics/
Graphics/Xpm.py
Graphics/Vector/
Graphics/Vector/init.py
Graphics/Vector/Svg.py
Graphics/init.py

The Svg.py file has this content:

#!/usr/bin/env python3
from ..Graphics import Xpm
SVG = 1

Here are 3 interactive actions, one each for 3.0, 3.1, and 3.2rc1:

$ python30
Python 3.0.1 (r301:69556, Jul 15 2010, 10:31:51) 
[GCC 4.4.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from Graphics.Vector import *
>>> Svg.SVG
1

$ python31
Python 3.1.2 (r312:79147, Jul 15 2010, 10:56:05) 
[GCC 4.4.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from Graphics.Vector import *
>>> Svg.SVG
1

$ ~/opt/python32rc1/bin/python3
Python 3.2rc1 (r32rc1:88035, Jan 16 2011, 08:32:59) 
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from Graphics.Vector import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "Graphics/Vector/Svg.py", line 2, in <module>
    from ..Graphics import Xpm
ImportError: No module named Graphics

So clearly 3.0 and 3.1 have the same behavior as each other; and this is different from 3.2rc1, and Georg says that 3.0 and 3.1 have a bug and that 3.2rc1 is correct.

PS R. David Murray suggests that this might be related to
http://bugs.python.org/issue7902

[ncoghlan]

Yeah, 7902 was a bug that tried to do an absolute import if an explicit relative import failed to find anything (i.e. it had inherited the old implicit relative import fallback, which was entirely inappropriate for the new use case).

Since the significant import in these examples should correctly be written as "from .. import Xpm", it should fail in 2.6.6 and 3.1.3 as well.

If you could confirm that at least 3.1.3 also gives the expected error message, we'll close this as a dupe of 7902.

[mark-summerfield]

I just installed 3.1.3 and it does indeed give the import error:

Python 3.1.3 (r313:86834, Jan 17 2011, 16:29:46) 
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from Graphics.Vector import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "Graphics/Vector/Svg.py", line 2, in <module>
    from ..Graphics import Xpm
ImportError: No module named Graphics