[PyQt] Building PyQt5.7 with Qt5.6: issues

[Thomas Petazzoni]

Hello,

According to
http://pyqt.sourceforge.net/Docs/PyQt5/introduction.html#an-explanation-of-version-numbers:

"""
Therefore, for PyQt5 v5.n.* the following are true.

    It will build against any version of Qt v5, but will not support
    any new features introduced in Qt v5.n+1 or later.
"""

Unfortunately, we are seeing build issues when building PyQt5.7 against
Qt5.6. Here are some of the issues we are seeing:

 - sipQtCoreQRect.cpp:1552:40: error: 'const class QRect' has no member
   named 'transposed'

   And indeed the transposed() method in QRect was added in Qt5.7, so
   it's not available in Qt5.6. See
   http://doc.qt.io/qt-5/qrect.html#transposed.

   More build log available at:
   http://autobuild.buildroot.net/results/030/0306710e0f39591dba74f24aff40f7f094bcfa6e/build-end.log

 - sipQtCoreQIODevice.cpp:1627:30: error: 'const class QIODevice' has
   no member named 'readChannelCount'

   sipQtCoreQIODevice.cpp:1652:30: error: 'const class QIODevice' has
   no member named 'writeChannelCount'

   writeChannelCount() was also introduced in Qt 5.7, see
   http://doc.qt.io/qt-5/qiodevice.html#writeChannelCount.

 - sipQtCoreQMetaObject.cpp:1086:30: error: 'const struct QMetaObject'
   has no member named 'inherits'

   The inherits() method of QMetaObject was also added in Qt 5.7, see
   http://doc.qt.io/qt-5/qmetaobject.html#inherits

So, is it really supported to build PyQt5.7 with Qt5.6, like the PyQt
website claims? Or am I reading the PyQt website incorrectly?

Thanks for your input,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com