Python 3

[jpopelka]

any plans to port to Python 3 ?

I for example see:

python3 -c 'import redhawk.common.selector'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3.4/site-packages/redhawk/common/selector.py", line 75, in <module>
    import _selector
ImportError: No module named '_selector'

[ncoghlan]

I started work on an initial PR for Python 2/3 compatibility at ncoghlan@e924aec

The major changes in the initial patch are:

• switching to explicit relative imports
• using print as a function rather than as a statement
• using the "exception as name" except clause syntax rather than "exception, name"
• wrapping various builtins with "list" calls to preserve the Py2 behaviour of producing a list
• using six.moves to cope with some standard library rearrangements

The modified implementation mostly passes "python setup.py test" under Python 3.4, but I haven't checked it for Python 2.6/7 compatibility yet. There are also a couple of test failures: test_c_declarations and test_c_expressions both fail to locate their "test_descriptions" file (and switching those lines to use os.path.join didn't make a difference).

[spranesh]

Wow, thanks, @ncoghlan! I had a preliminary peek and it looks good - I'd be happy to review and upstream it when you are done. Let me know if anything seems particularly hard or unwieldy - I'd be happy to help.

[spranesh]

@jpopelka: Thank you for filing an issue. Just to clarify, when you say port do you mean:

1. Redhawk parses and queries python3 codebases.
2. Or Redhawk source code should be python3 compatible?

@ncoghlan's change should address the latter, but not the former.

Right now, I don't have the bandwidth to work on adding Python3 support in the LAST. I suspect I can get around to this over the next quarter, but I cannot make a firm guarantee at this time.

I can provide pointers if that'd help. I'd be happy to review and accept patches!

[ncoghlan]

This issue is specifically about getting Redhawk itself running on Python 3 (Jiri & I are working on the same project, and we're interested in running that on 3.4 or 3.5 instead of 2.7)

I filed #2 to cover eventually supporting the new syntactic constructs introduced in 3.3 and 3.5, but most of the code bases we're interested in analysing won't be using those new constructs yet.

[spranesh]

Thanks for clarifying and triaging!

[bkabrda]

Hi, so I pushed several commits to @ncoghlan's py3-compat branch. All the tests that pass for me on Python 2 now also pass on Python 3; there are however 31 tests (out of 234) that fail on both versions. I'm quite sure that the failures are the same in Python 2 and 3, so it seems I didn't break anything. Nick, feel free to review my commits and create a PR if you think this is good enough. @spranesh, feel free to review any time, I'd be glad for any comments/suggestions.

[ncoghlan]

PR submitted: #3

@bkabrda GitHub was clever enough to migrate my and @jpopelka's comments on the initial python-modernize output from the fork, so you may want to look into those.

[bkabrda]

Thanks. I had a look and pushed one more commit that addresses the issues. The PR is ready to be reviewed by @spranesh

[bkabrda]

@spranesh sorry to bother you again, but could you please release a new Redhawk version on PyPI? It'd really help me. Now I need to install things from git by pip if I want Python 3 support which is not very nice - I would like to be able to install from PyPI with Python 3 support. Thanks!

[bkabrda]

@spranesh ping, any plans for releasing new version of Redhawk with Py3 support?

[spranesh]

Yes, I plan to do a release with your changes within the next week or two.

[jpopelka]

Hello @spranesh
It's been few weeks and we'd like to know what's your realistic estimation of the release date. Don't feel pressed - we just want to finish the porting of our project to Python 3 and need to decide whether to still wait for the release or start running redhawk from the repository. Thank you !

[spranesh]

Sorry for dropping the ball on this. Please expect a release by August 23rd (i.e, two weeks from now).

[ncoghlan]

Not a problem! Thanks for setting a target date, though - while we've always had the option of installing 68a7400 directly from version control, we do consider it preferable to run on officially released versions of dependencies :)

[ncoghlan]

The 1.2.3 release now includes experimental support for running on Python 3.

However, as noted in #2, additional work will be needed to analyse new Python 3 specific syntax, and @bkabrda indicated in #3 (comment) that there can be problems with analysing Python 2 only syntax when running on Python 3.