I have the impression the lldb can run with Python 3.
I couldn't find anything in the docs, but the build system seems prepared fort hat and it also uses six (a comaptibility layer to support both Python major versions).
Can we switch it in Fedora? Does anything block us?
Mea culpa. It seems it is not:
When i switch the build to python 3, it fails during bytecompilation, there is at least one Legacy Python print.
+ /usr/lib/rpm/brp-python-bytecompile /usr/bin/python 1
Bytecompiling .py files below /builddir/build/BUILDROOT/lldb-6.0.0-4.fc29.x86_64/usr/lib64/python3.6 using /usr/bin/python3.6
*** Error compiling '/builddir/build/BUILDROOT/lldb-6.0.0-4.fc29.x86_64/usr/lib64/python3.6/site-packages/lldb/utils/symbolication.py'...
File "/usr/lib64/python3.6/symbolication.py", line 206
print 'error: invalid section info string "%s"' % s
SyntaxError: Missing parentheses in call to 'print'. Did you mean print('error: invalid section info string "%s"' % s)?