Bug when build ROOT with python3.7

ROOT
1

_ROOT Version: 6.15
_Platform: macos
_Compiler: mac default

bug.md buffers
/Users/chenxu/software/ROOT/git/bindings/pyroot/src/PyRootType.cxx:103:22: error:
¦ ¦ cannot initialize a variable of type ‘char *’ with an rvalue of type
¦ ¦ 'const char ’
¦ ¦ ¦ ¦ ¦ ¦ ¦char cppname = PyROOT_PyUnicode_AsString(pycppname);
¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [bindings/pyroot/CMakeFiles/PyROOT.dir/src/PyRootType.cxx.o] Error 1

/Users/chenxu/software/ROOT/git/bindings/pyroot/src/TPyROOTApplication.cxx:101:16: error:
¦ ¦ cannot initialize a variable of type ‘char *’ with an rvalue of type
¦ ¦ 'const char ’
¦ ¦ ¦ ¦char argi = PyROOT_PyUnicode_AsString( PyList_GET_ITEM( argl, i ) );
¦ ¦ ¦ ¦ ¦ ¦ ¦^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
/Users/chenxu/software/ROOT/git/bindings/pyroot/src/TPyROOTApplication.cxx:107:22: error:
¦ ¦ assigning to ‘char *’ from incompatible type ‘const char *’
¦ ¦ ¦ ¦argv[ i ] = argi;
¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦^~~~
1 error generated.

there may be some other bugs ,I’m still debugging

2

That particularly piece of code is so wrong on so many levels. In fact, it was the impetus for me to fork PyROOT, b/c that’s what cancerous bitrot looks like. :confused:

The whole cppname business was completely rewritten in cppyy master and this particular function is not needed in the first place, but to have a localized fix, at least it should not only add the ‘const’, but also push the Py_DECREF two statements down. Either way, the scope id is a data member of the type instance, so GetScope() is completely superfluous.

3

You should probably also replace ‘_PyObject_GC_TRACK’ by ‘PyObject_GC_Track’ (in Pythonize.cxx). The former is a macro version of the latter, but accesses a variable that is no longer exported in 3.7, leading to a missing symbol (_PyGC_generation0). This was the only issue I found in cppyy master to support 3.7 (fixes are in repo; to be released soon enough).

There used to be a performance improvement, but I see no adverse effect today by replacing the macro with the function call.

4

Hi,

The bug is being tracked here:

https://sft.its.cern.ch/jira/browse/ROOT-9521

Enric

5

cppyy master with support for p3.7 has been released on PyPI.