Installation fails during Fortran compilation in latest Ubuntu LTS (18.04)

[egparedes]

I haven't managed to install ttpy in two different computers with Ubuntu 18.04 LTS. In the past I've installed ttpy in other systems without problems and I followed the instructions in the README file as usual, but this time does not work. The installation crashes during fortran compilation. I've tried using both gfortran-6 and gfortran-7 compilers in the Ubuntu repositories but it fails with a very similar error message:

Fortran f77 compiler: /usr/bin/gfortran -Wall -g -ffixed-form -fno-second-underscore -fPIC -O3 -funroll-loops
Fortran f90 compiler: /usr/bin/gfortran -Wall -g -fno-second-underscore -fPIC -O3 -funroll-loops
Fortran fix compiler: /usr/bin/gfortran -Wall -g -ffixed-form -fno-second-underscore -Wall -g -fno-second-underscore -fPIC -O3 -funroll-loops
creating build/temp.linux-x86_64-3.6/tt
creating build/temp.linux-x86_64-3.6/tt/tt-fort
creating build/temp.linux-x86_64-3.6/tt/tt-fort/print
compile options: '-I/home/henrique/.virtualenvs/tttest/lib/python3.6/site-packages/numpy/core/include -Ibuild/temp.linux-x86_64-3.6 -Ibuild/temp.linux-x86_64-3.6 -Ibuild/temp.linux-x86_64-3.6 -I/usr/include/python3.6m -I/home/henrique/.virtualenvs/tttest/include/python3.6m -c'
extra options: '-Jbuild/temp.linux-x86_64-3.6 -Ibuild/temp.linux-x86_64-3.6'
gfortran:f90: tt/tt-fort/print/putstrmodule.F90
gfortran:f90: tt/tt-fort/print/dispmodule.f90
tt/tt-fort/print/dispmodule.f90:1248:0:

     character(widthmax_dint(x, fmt)) :: sa(size(x))

internal compiler error: in conv_function_val, at fortran/trans-expr.c:3717
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-7/README.Bugs> for instructions.
tt/tt-fort/print/dispmodule.f90:1248:0:

     character(widthmax_dint(x, fmt)) :: sa(size(x))

internal compiler error: in conv_function_val, at fortran/trans-expr.c:3717
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-7/README.Bugs> for instructions.
error: Command "/usr/bin/gfortran -Wall -g -fno-second-underscore -fPIC -O3 -funroll-loops -I/home/henrique/.virtualenvs/tttest/lib/python3.6/site-packages/numpy/core/include -Ibuild/temp.linux-x86_64-3.6 -Ibuild/temp.linux-x86_64-3.6 -Ibuild/temp.linux-x86_64-3.6 -I/usr/include/python3.6m -I/home/henrique/.virtualenvs/tttest/include/python3.6m -c -c tt/tt-fort/print/dispmodule.f90 -o build/temp.linux-x86_64-3.6/tt/tt-fort/print/dispmodule.o -Jbuild/temp.linux-x86_64-3.6 -Ibuild/temp.linux-x86_64-3.6" failed with exit status 1

It looks to me like a weird bug in gfortran, but I'm not a fortran expert so I don't know how to fix it. Any ideas?

Thanks for your time.

[daskol]

Yeah, I have the same issue with my gfortran 7.3.0 and 8.1.0. Try other fortran compiler. For example, ifort 18.0.2 works properly.

I have already reported the bug however there is no any activity. You could report the bug to gcc community too in order to bring more attention to the issue.

[egparedes]

Thanks for the tip, @daskol. It works for me now using different gfortran 4.x and gfortran 5.x versions, so they probably created the bug affecting ttpy in some gfortran 6.x version. Is there anyway I can upvote your GCC bug report? Can you send me some bug reference number?

[daskol]

This bug is fixed in GNU Fortran 9.0. Most likely, the fix will be backported later. Here is link to bug report.