[Qgis-developer] OSGEO4W vs. Mac OS X Qt version (or ~34 plugins slightly broken)

[William Kyngesburye]

On May 10, 2012, at 11:43 AM, Larry Shaffer wrote:

> Hi William,
> 
> On Thu, May 10, 2012 at 8:26 AM, William Kyngesburye <woklist at kyngchaos.com> wrote:
> On May 9, 2012, at 12:08 PM, Larry Shaffer wrote:
> 
> > During a recent audit of almost every PyQGIS plugin (casually studying repetitive design patterns) and helping some users on gis.stackexhange.com [0] I have come across an issue that may affect over 30 plugins (for now, only on Mac).
> >
> > From what I can gather, William Kyngesburye's Mac builds (and Unix/Linux, too?) consistently use a current, stable version of Qt, now at 4.8, while the OSGEO4W package is at 4.4 [1]. This hasn't been an issue since, I believe (and assume), the bundled Qt in Mac builds included Qt3 support. The most recent 1.7.4 Mac version appears to have a bundled Qt with no Qt3 support (is this correct?).
> >
> I haven't included Qt3Support since QGIS 1.2, when the last of the Qt3 usage was removed (I think GRASS plugin was the last holdout).
> 
> I'm referring to Qt4 being compiled with the legacy '-qt3support' option (supposedly on by default [0]), not direct Qt3 support (frameworks, etc). Recently, when there was an issue with QWebKit on 10.6, you posted a configure line for compiling Qt4 to fix the problem [1]. I noted that you chose the '-no-qt3support' option. Is that the same Qt you used for bundling the recent QGIS 1.7.4-x? Had you nixed -qt3support in past builds, or used Nokia's pre-compiled Qt4 builds with '-qt3support'?
> 
> [0] http://qt-project.org/doc/qt-4.8/configure-options.html
> [1] http://osgeo-org.1560.n6.nabble.com/OS-X-QtWebKit-problem-fixed-PyQwt-still-broken-td4513113.html#a4519323
>  
"Qt3Support" is the library/framework you get with the qt3support compile option.  I don't think there is anything extra in the other frameworks/libraries when you compile with this option.

> > This has caused many PyQGIS plugins to fail to launch on Mac, due to their use of a Qt3-only QAction signal of activated() in a plugin's initGui() method. Basically, the plugin does not launch (i.e. does nothing), with no error. However, for Windows users, the plugin launches fine, causing problems when trying to offer cross-platform support for plugin issues.
> >
> > Can someone else verify these findings?
> >
> > I am slightly surprised Qt3 is still supported, and think dropping its support sounds like a good idea, especially for QGIS version 1.8 or >, but certainly don't know all the details on versioning for QGIS distributions. I understand this may cause problems with the OSGEO4W package. (btw: Why is it still on Qt 4.4?)
> >
> I would assume that Qt3 usage in external plugins would require support in PyQt, but PyQt has never compiled a PyQt3 module for me, and I'm not sure if it can, or how.
> 
> Can you think of anything else that might have caused this issue, via differences between your 1.7.3 and 1.7.4 builds? It may be even between the latest 1.7.4-x builds. I can try to re-install each of the versions to find when the issue occurs.
> 
There is something going on with the Qt 4.8.1 that I upgraded to in QGIS 1.7.4 (1.7.3 used Qt 4.8.0, which had the QtWebKit problem) - there are mysterious crashes is various places.  There may be other problems in the latest Qt that don't cause a crash, but break plugins.

>  
> > Here are the plugins I have found that use the deprecated activated() signal, including two core C++ [2]
> 
> This is odd because those plugins then should not even compile if Qt3 is missing.  And spatialquery works for me without Qt3Support.  (GRASS works, but has its own problems)
> 
> The 'Hello World' plugin is the simplest for testing/exhibiting the issue [2]. Odd that I get no launch of Spatial Query plugin, on all my 1.7.4-4 installs, but you're having success with it.
> 
> [2] http://plugins.qgis.org/plugins/HelloWorld/
> 
I tried on OSX 10.7, I'll try it this evening on OSX 10.6 when I get home.

>  
> > and a ZIP archive of the particular files that I found to contain that signal [3]. Without a complete examination of each plugin, I am not entirely certain all of the signals are of QAction. I tried to include only those that appear to be. (Note: there may be more uses of Qt3 deprecated methods, etc.)
> >
> > Please correct me if I am off on my assessment of this situation, or if I am late to the discussion.
> >
> > [0] http://gis.stackexchange.com/a/22953/6725 , http://gis.stackexchange.com/a/24860/6725
> > [1] http://trac.osgeo.org/osgeo4w/wiki/pkg-qt4-libs
> > [2] http://dl.dropbox.com/u/4058089/qgis/plugins_contain-qt3activated.txt
> > [3] http://dl.dropbox.com/u/4058089/qgis/plugins_contain-qt3activated.zip
> >
> > Regards,
> >
> > Larry Shaffer
> > Dakota Cartography
> > Black Hills, South Dakota
> > _______________________________________________
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> > Qgis-developer at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/qgis-developer
> 
> -----
> William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
> http://www.kyngchaos.com/
> 
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> 
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> 
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-----
William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
http://www.kyngchaos.com/

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