Incompatibility between python 2.7 and C++17

[fabiocos]

During the test of #23194 a clang compilation failure has appeard, as seen in

https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-23194/27923/buildClang.log

Compiling edm plugin /build/cmsbld/jenkins/workspace/ib-any-integration/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/Integration/test/HistProducer.cc
In file included from /build/cmsbld/jenkins/workspace/ib-any-integration/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/Framework/src/EventProcessor.cc:46:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/cms/cmssw-patch/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/PythonParameterSet/interface/PythonProcessDesc.h:4:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/cms/cmssw-patch/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/PythonParameterSet/interface/BoostPython.h:5:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python.hpp:11:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python/args.hpp:8:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python/detail/prefix.hpp:13:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python/detail/wrap_python.hpp:151:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/Python.h:85:
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/unicodeobject.h:534:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register PyObject obj, / Object */
^~~~~~~~~
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/unicodeobject.h:553:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register PyObject obj / Object */
^~~~~~~~~
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/unicodeobject.h:575:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register const wchar_t w, / wchar_t buffer */
^~~~~~~~~
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/unicodeobject.h:593:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register wchar_t w, / wchar_t buffer */
^~~~~~~~~
Compiling edm plugin /build/cmsbld/jenkins/workspace/ib-any-integration/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/Integration/test/ThingExtSource.cc
In file included from /build/cmsbld/jenkins/workspace/ib-any-integration/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/Framework/src/EventProcessor.cc:46:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/cms/cmssw-patch/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/PythonParameterSet/interface/PythonProcessDesc.h:4:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/cms/cmssw-patch/CMSSW_10_2_X_2018-05-12-1100/src/FWCore/PythonParameterSet/interface/BoostPython.h:5:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python.hpp:11:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python/args.hpp:8:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python/detail/prefix.hpp:13:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/boost/1.63.0-omkpbe2/include/boost/python/detail/wrap_python.hpp:151:
In file included from /cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/Python.h:94:
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/stringobject.h:173:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register PyObject obj, / string or Unicode object */
^~~~~~~~~
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/stringobject.h:174:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register char *s, / pointer to buffer variable */
^~~~~~~~~
/cvmfs/cms-ib.cern.ch/nweek-02523/slc6_amd64_gcc630/external/python/2.7.11-omkpbe2/include/python2.7/stringobject.h:175:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register Py_ssize_t len / pointer to length variable or NULL
^~~~~~~~~

The problem appears unrelated to the changes in the PR , but it has been put into evidence by the tests of the package involved.

[cmsbuild]

A new Issue was created by @fabiocos Fabio Cossutti.

@davidlange6, @Dr15Jones, @smuzaffar, @fabiocos can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[smuzaffar]

this has been addressed by patching python 2.7 to avoid register keyword

cms-externals/cpython@583c0f2