Reintegrate qt4reactor into twisted

[jknight]

So, the inevitable has happened, and there are now finally LGPL python bindings for the previously LGPL'd Qt, called "PySide":  http://codeposts.blogspot.com/2009/08/lgpl-python-bindings-for-qt-released.html

Supposedly, PySide is even API compatible with PyQt: just replace every PyQt4 import with a PySide import.

It'd thus be nice to get a qt4reactor like ( http://github.com/ghtdak/qtreactor/tree/master) merged back into twisted, but written for PySide instead of PyQt4.

I'd additionally note that if the compatibility is as it is claimed, an end-user who wants to use the designed-for-PySide qtreactor with PyQt4 -- perhaps because they already have PyQt4 installed and do not have PySide installed -- could pretty trivially poke a thing into sys.modules['PySide.QtCore'] first before calling qt4reactor.install(). But of course that's nothing to do with Twisted.

[exarkun]

Sounds good.

We need to:

• Figure out what the license is on qt4reactor. AIUI, a bunch of people have contributed to it, Glenn being the most recent developer. Hopefully they'll all be happy with MIT.
• Get a buildslave set up with PySide installed to run Qt tests
• Fix whatever test failures that slave points out (eg, hopefully there'll be one for < http://twistedmatrix.com/pipermail/twisted-python/2009-August/020267.html>, if not we might want to expand our test coverage a bit).
• Gooooooooo

[ghtdak]

I'm cool with changing to whatever license makes sense. IIRC, the other contributers would include Therve, Itmar Shtull-Trauring and Gabe Rudy

Maintainer: U{Glenn H Tarbox, PhD<mailto:glenn@…>} Previous maintainer: U{Itamar Shtull-Trauring<mailto:twisted@…>} Original port to QT4: U{Gabe Rudy<mailto:rudy@…>}

The current repo is under the launchpad tx project. Not sure if any clones are up at github with fixes we'd want included.

[sc]

Replying to ghtdak:

I'm cool with changing to whatever license makes sense. IIRC, the other contributers would include Therve, Itmar Shtull-Trauring and Gabe Rudy Maintainer: U{Glenn H Tarbox, PhD<mailto:glenn@…>} Previous maintainer: U{Itamar Shtull-Trauring<mailto:twisted@…>} Original port to QT4: U{Gabe Rudy<mailto:rudy@…>}

Following up on this mailing list thread as to the status of the qt4reactor and its licensing:

 http://twistedmatrix.com/pipermail/twisted-python/2010-June/022457.html

It would seem PySide has reached the point where it should be a viable alternative to PyQt, without the license complications.

It is still necessary to attain permission to re-release the qt4reactor code under Twisted's MIT license however.

[Killarny]

I've followed up a bit on the thread referenced by sc, and it appears that the qt4reactor has already been relicensed to something very permissive.

See:  http://twistedmatrix.com/pipermail/twisted-python/2010-June/022470.html and  https://github.com/ghtdak/qtreactor/blob/master/LICENSE

It seems that only the testing requirements outlined by exarkun above still remain for this ticket, before the code living at  https://github.com/ghtdak/qtreactor can be merged into Twisted.

[michaelnt]

I've made some updates to the qtreactor at  https://github.com/ghtdak/qtreactor and it now passes the complete Twisted test suite with the possible exception of UDP multicast.

It probably needs some more tests, the dpaste link in the email exarkun references can't be viewed anymore.

I've also added a win32event interface so this reactor can be used with serial ports on Windows.

[michaelnt]

I created a branch on github that has commits to

• undo the removal of the original qtreactor,
• update qtdemo.py to use Qt4, PySide and a WebKit view rather than plain html text
• update qtreactor with the latest code from qt4reactor

 https://github.com/michaelnt/twisted/commits/qt4reactor

[michaelnt]

Added patch that re-integrates the qtreactor and updates the qtdemo app.

Removed the win32event interface as this might be better in a separate ticket.

[thijs]

A coupe of coding standard issues to be resolved before this lands:

• copyright header should be bumped from 2001-2004 to 2001-2011
• don't add maintainer email addresses to the docstring to prevent spam and outdated info in the source code
• docstrings on 3 lines instead of 2:

  """
  foo
  """
  

[michaelnt]

Patch update to address review comments from thijs:

• Updated copyright
• Tidied up docstrings
• Removed maintainer names and emails

[thijs]

Thanks for the updates. I'd like to try this out, but applying it to the trunk throws some errors:

thijs@ubuntu:~/workspaces/opensource/Twisted/trunk$ patch -p0 < qtreactor-3977.patch 
patching file b/doc/core/examples/qtdemo.py
patching file b/twisted/internet/qtreactor.py
Hunk #1 FAILED at 1.
1 out of 1 hunk FAILED -- saving rejects to file b/twisted/internet/qtreactor.py.rej
patching file b/twisted/internet/test/reactormixins.py
Hunk #1 FAILED at 51.
1 out of 1 hunk FAILED -- saving rejects to file b/twisted/internet/test/reactormixins.py.rej
The next patch would delete the file a/twisted/plugins/twisted_qtstub.py,
which does not exist!  Assume -R? [n] 
Apply anyway? [n] y
patching file a/twisted/plugins/twisted_qtstub.py
Reversed (or previously applied) patch detected!  Assume -R? [n] 
Apply anyway? [n] 
Skipping patch.
1 out of 1 hunk ignored -- saving rejects to file a/twisted/plugins/twisted_qtstub.py.rej
patching file b/twisted/plugins/twisted_reactors.py
Hunk #1 FAILED at 36.
1 out of 1 hunk FAILED -- saving rejects to file b/twisted/plugins/twisted_reactors.py.rej

[michaelnt]

The patch came from git so it has to be applied as

patch -p1 < qtreactor-3977.patch

[michaelnt]

Updated the patch and checked that it will apply to trunk as

patch -p0 < qtreactor-3977.patch

[thijs]

Thanks for the updates. I'm using Ubuntu 10.10 maverick and installed pyside 1.0beta4 in the stock ubuntu python2.6 and it runs fine (with some non-related info printed at the console):

thijs@ubuntu:~/workspaces/opensource/Twisted/trunk$ /usr/bin/python2.6 doc/core/examples/qtdemo.py 
/home/thijs/.gtkrc-2.0:11: Unable to locate image file in pixmap_path: "Arrows/arrow-up_.png"
/home/thijs/.gtkrc-2.0:15: Overlay image options specified without filename
/home/thijs/.gtkrc-2.0:21: Unable to locate image file in pixmap_path: "Arrows/arrow-up_.png"
/home/thijs/.gtkrc-2.0:25: Overlay image options specified without filename

Is it possible to auto-load the twisted site in the webkit panel, because it currently shows a blank page with the url in the addressbar, making it seem that it couldn't be loaded (although it does when you hit enter in the addressbar). See attached screenshot.

[thijs]

pyflakes also reports some unused imports:

$ pyflakes qtdemo.py 
qtdemo.py:13: 'QObject' imported but unused
qtdemo.py:13: 'QCoreApplication' imported but unused
qtdemo.py:13: 'QSocketNotifier' imported but unused
qtdemo.py:13: 'QTimer' imported but unused
qtdemo.py:14: 'QEventLoop' imported but unused
qtdemo.py:15: 'QtCore' imported but unused

[michaelnt]

Updated patch

• removed un-needed imports
• qtdemo now loads default url on start up.

I think the .gtkrc warning are something to do with theming and are presumably wrong on your setup. The demo app doesn't have any icons so we should ignore these warnings.

[thijs]

Replying to michaelnt:

I think the .gtkrc warning are something to do with theming and are presumably wrong on your setup. The demo app doesn't have any icons so we should ignore these warnings.

Totally.

Looks good here:

There's a couple of places that have list of reactors (in docstrings and documentation) that would also need an update.

[michaelnt]

Documentation patch

[michaelnt]

Added a patch that updates the documentation.

I searched for epoll as a way to discover reactor documentation or references in the source code and couldn't find anywhere else that needs updating.

[thijs]

(In [30761]) Branching to 'qt4reactor-pyside-3977'

[thijs]

(In [30827]) Apply qtreactor-3977.patch, refs #3977

[thijs]

(In [30828]) Apply documentation-3977.patch, refs #3977

[thijs]

(In [30829]) Update docs, refs #3977

[thijs]

Replying to michaelnt:

Added a patch that updates the documentation. I searched for epoll as a way to discover reactor documentation or references in the source code and couldn't find anywhere else that needs updating.

Thanks, I created a branch, applied the tickets and made some cosmetic changes. Could you also add a line to the Reactor Functionality table in the  choosing-reactor howto? I'm not sure how stable it is, but tested on ubuntu.

[thijs]

Replying to exarkun:

* Get a buildslave set up with PySide installed to run Qt tests

Any chance you could supply a buildslave michaelnt?

[michaelnt]

Update on progress.

The Good News is I have set up a buildslave

 http://buildbot.twistedmatrix.com/builders/windows7-32-py2.7

The bad news is that

• running trial with the select reactor some of the QtReactor tests fail, but are incorrectly marked as skips by trial.
• Running trial with the qt reactor causes python to crash, and a dialog to get displayed by windows.

I'll keep looking into this.

[michaelnt]

All the tests should pass after this diff is applied if run against PySide 1.0 15759_15758.diff

Can someone apply this to the branch.

[exarkun]

(In [31243]) Apply 15759_15758.diff

refs #3977

[michaelnt]

Build results at  http://buildbot.twistedmatrix.com/builders/windows7-32-py2.7/builds/79

One failure when running the default reactor, test_qt4reactor failing to import twisted_qtstub. When running the complete test suite using the qt reactor python crashes.

If I re-run the individual tests they pass, I suspect a bug in PySide.

[thijs]

Replying to michaelnt:

Build results at  http://buildbot.twistedmatrix.com/builders/windows7-32-py2.7/builds/79 One failure when running the default reactor, test_qt4reactor failing to import twisted_qtstub. When running the complete test suite using the qt reactor python crashes.

That stub was removed in this branch (as part of [attachment:qtreactor-3977.patch in r30827)? Also fails with the qt reactor..

If I re-run the individual tests they pass, I suspect a bug in PySide.

When running this locally the qt reactor python doesn't crash and the test suite completes  with errors:

$ uname --all
Linux aspiration 3.0.0-16-generic #28-Ubuntu SMP Fri Jan 27 17:44:39 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
$ python -c "from PySide import __version__ as v; print v"
1.1.0
$ trial --reactor=qt twisted
...
Ran 6897 tests in 76.736s

FAILED (skips=767, expectedFailures=18, failures=13, errors=11, successes=6089)

[thijs]

(In [33611]) Merge forward, refs #3977

[thijs]

(In [33610]) Branching to 'qt4reactor-pyside-3977-2'