[Pythonmac-SIG] py2app cannot move to target thread error

[Daniel Miller]

> Has anyone within earshot of this list successfully built a PyQt  
> app with SQL support using py2app?  I've been poking and prodding  
> at the problem for a few months now and I'm no closer to a solution  
> to the "cannot move to thread ..." error.

Yes, I think I got this to work recently with Qt3. If I remember  
correctly, it was due to loading multiple versions of the QtCore  
library. I think the problem has to do with with Qt plugins not being  
handled correctly by py2app, and thus the plugins are not being  
loaded from within in the app bundle. Here's the relevant snippets  
from the setup.py that I used:

name = "program"

setup(
     name = name,
     ...
     setup_requires=["py2app"],
     options = {
         "py2app": dict(
             argv_emulation=True,
             frameworks=[
                 "/path/to/qt/plugins/sqldrivers/libqsqlpsql.dylib",
             ],
         )
     },
     ...
)

if "py2app" in sys.argv:
     # fix the bundle created by py2app
     def do(cmd):
         print " ".join(cmd)
         subprocess.call(cmd)
     appdir = os.path.abspath(os.path.join("dist", name + ".app",  
"Contents"))

     ...

     # move the sql driver where Qt will find it
     plugin_dir = join(appdir, "Resources", "sqldrivers")
     os.makedirs(plugin_dir)
     do(["mv", join(appdir, "Frameworks", "libqsqlpsql.dylib"),  
plugin_dir])


It might be necessary to put the sqldrivers in Contents/MacOS rather  
than Contents/Resources. I was doing a lot of other strange stuff  
with this app because I was trying to bundle a bunch of legacy C apps  
into a stand-alone application that would run on Mac OS.

I'm not familiar with using py2app with macports libraries. But it's  
a red flag to me that your app is loading libraries from /opt/local/...

> dyld: loaded: /opt/local/libexec/qt4-mac/plugins/sqldrivers/ 
> libqsqlpsql.bundle
> dyld: loaded: /opt/local/lib/postgresql83/libpq.5.dylib
> dyld: loaded: /opt/local/libexec/qt4-mac/lib/QtSql.framework/ 
> Versions/4/QtSql
> dyld: loaded: /opt/local/libexec/qt4-mac/lib/QtCore.framework/ 
> Versions/4/QtCore
> dyld: loaded: /opt/local/lib/libz.1.dylib
> dyld: loaded: /opt/local/lib/libssl.0.9.8.dylib
> dyld: loaded: /opt/local/lib/libcrypto.0.9.8.dylib

Shouldn't those libraries be in your app bundle? I would expect to  
see them loading from somewhere like /path/to/your/program.app/ 
Contents/MacOS/../Frameworks

This leads me to believe that you are in fact loading more than one  
Qt library, which is causing the "cannot move to thread" error, and  
is probably due to Qt using the wrong plugin(s).

One more thing: I think the plugin resolution logic in Qt changed  
between Qt3 and Qt4, so the recipe I gave above might not work.  
You'll need to look that up in the Qt documentation.

~ Daniel