using sip-wheel on MacOS

[Steve Borho]

> On Apr 29, 2020, at 3:02 AM, Phil Thompson <phil at riverbankcomputing.com> wrote:
> 
> On 29/04/2020 02:52, Steve Borho wrote:
>>> On Apr 28, 2020, at 3:46 PM, Phil Thompson <phil at riverbankcomputing.com> wrote:
>>> On 28/04/2020 18:49, Steve Borho wrote:
>>>>> On Apr 28, 2020, at 3:58 AM, Phil Thompson <phil at riverbankcomputing.com> wrote:
>>>>> On 28/04/2020 04:55, Steve Borho wrote:
>>>>>> Hello,
>>>>>> On Linux and Windows I can use sip-wheel to build binary wheels that
>>>>>> will gladly use the Qt libraries packaged by PyQt5, by compiling
>>>>>> against the same local version of Qt.
>>>>>> But when I try this on Mac, it is linking in the full paths to the
>>>>>> local (homebrew) Qt libraries
>>>>>> $ otool -L foo.cpython-37m-darwin.so
>>>>>> foo.cpython-37m-darwin.so:
>>>>>> 	/usr/local/opt/qt/lib/QtPrintSupport.framework/Versions/5/QtPrintSupport
>>>>>> (compatibility version 5.14.0, current version 5.14.1)
>>>>>> 	/usr/local/opt/qt/lib/QtOpenGL.framework/Versions/5/QtOpenGL
>>>>>> (compatibility version 5.14.0, current version 5.14.1)
>>>>>> 	/usr/local/opt/qt/lib/QtWidgets.framework/Versions/5/QtWidgets
>>>>>> (compatibility version 5.14.0, current version 5.14.1)
>>>>>> 	/usr/local/opt/qt/lib/QtDataVisualization.framework/Versions/5/QtDataVisualization
>>>>>> (compatibility version 5.14.0, current version 5.14.1)
>>>>>> 	/usr/local/opt/qt/lib/QtGui.framework/Versions/5/QtGui (compatibility
>>>>>> version 5.14.0, current version 5.14.1)
>>>>>> I see that sip-wheel has an option for:
>>>>>> --target-qt-dir DIR   the Qt libraries will be found in DIR when the wheel
>>>>>>                      is installed
>>>>>> but it is not clear how to target the PyQt5 packaged Qt libraries.
>>>>>> Has anyone else tackled this?  Thanks
>>>>> Assuming you are going to package a Qt installation with your wheel using pyqt-bundle at a later stage then pass '--target-qt-dir Qt/lib'.
>>>>> This will be documented in the next release of the PyQt docs.
>>>> Ideally the binaries in the wheel would use the Qt libraries in
>>>> ../PyQt5/Qt/lib/* from site-packages.
>>>> Does my app need to package its own copy of the Qt libraries if it
>>>> compiles its own shared library?
>>>> I just realized my Linux wheels have the same issue.  They are not
>>>> using PyQt5/Qt/lib, they are relying on the Qt libraries being present
>>>> where they were compiled.
>>> I'm not sure what it is you are trying to achieve. The wheels on PyPI are created by running sip-wheel using the --target-qt-dir. The wheel is compiled against a local Qt installation but targeted for a bundled copy of Qt. That wheel, if installed, would not run. pyqt-bundle is then run to bundle a copy of that local Qt installation to create a new wheel (the one uploaded to PyPI).
>> I have a PyQt application which implements some plotters in C++ and we
>> compile these into a shared library that links against several Qt
>> libraries. sip creates the Python bindings for it
>> When the application is installed as a wheel, ideally the plotter
>> shared library would link with the same Qt libraries that PyQt5 is
>> using, under site-packages/PyQt5/Qt/lib.
>> Any Qt libraries I package with my application could possibly be
>> incompatible with those that PyQt5 was compiled against and shipped
>> with.  Is it typical for apps that use both PyQt5 from Python and the
>> link to native Qt libraries to just ship the whole shebang (app + qt +
>> pyqt) in one wheel?  I’m curious how this is generally solved.
> 
> If you are relying on the PyQt5 wheels from PyPI then obviously you need to build against a compatible version of Qt. If you are using Qt libraries that are not bundled with the PyQt5 wheels then you will need to bundle them yourself in your own wheels.
> 
>> I actually have this almost working by adding this bit of shenanigans
>> to the main.py script:
>> import os
>> # relaunch the executable with site-packages/PyQt5/Qt/lib in library path
>> if 'APP_LIBPATH_HACK' not in os.environ:
>>    sitepackages = os.path.dirname(os.path.dirname(__file__))
>>    import sys
>>    if sys.platform in ('linux', 'darwin'):
>>        pyqt5 = os.path.join(sitepackages, 'PyQt5', 'Qt', 'lib')
>>    else:
>>        pyqt5 = os.path.join(sitepackages, 'PyQt5', 'Qt', 'bin')
>>    if os.path.isdir(pyqt5):
>>        if sys.platform == 'linux':
>>            os.environ['LD_LIBRARY_PATH'] = pyqt5
>>        elif sys.platform == 'darwin':
>>            os.environ['DYLD_FRAMEWORK_PATH'] = pyqt5
>>        else:
>>            os.environ['PATH'] = os.pathsep.join((pyqt5, os.environ['PATH']))
>>        os.environ['APP_LIBPATH_HACK'] = '1'
>>        os.execv(sys.argv[0], sys.argv)
>> It feels dirty, and doesn’t quite work because our plotter is linking
>> against QtDataVisualization and this Qt library is not packaged with
>> PyQt5, I presume because there are no Python bindings for it yet.  Is
>> support for QtDataVisualization on the roadmap?
> 
> PyQtDataVisualization was first released in March 2014.

Perfect, thanks.  I had found QScintilla in pypi, but didn’t think to look for that one.  Everything works now.

—
Steve