gps build no longer finding system includes for Ubuntu LTS (latest/Focal)

[steve-cs]

A recent change in the last 12-36 hours seems to have broken the gps build for me. It seems to be looking for python system includes in /usr/include/ when it has and should be looking in /usr/include/python3.8/. Builds of langkit and libadalang still work, so I don't think I trashed the python environment. But just to make sure I installed a fresh VM and I'm still seeing the problem. Might this be TB09-023 related?

Compile
   [Ada]          gps-main.adb
   [C]            python_support_gtk.c
In file included from /home/steve/gnat-builder/gps-build/gnatcoll_extras/src/python_support_gtk.c:19:
/usr/include/pygobject-3.0/pygobject.h:5:10: fatal error: Python.h: No such file or directory
    5 | #include <Python.h>
      |          ^~~~~~~~~~
compilation terminated.

If I create a link in /usr/include then this specific error goes away, but it immediately fails on another include.

Only one version of python is installed:

steve@steve-virtual-machine:/usr/include$ ls -l /usr/bin/python*
lrwxrwxrwx 1 root root       7 Apr 15  2020 /usr/bin/python -> python3
lrwxrwxrwx 1 root root       9 Dec  7 22:30 /usr/bin/python3 -> python3.8
-rwxr-xr-x 1 root root 5486352 Jul 28 05:59 /usr/bin/python3.8
lrwxrwxrwx 1 root root      33 Jul 28 05:59 /usr/bin/python3.8-config -> x86_64-linux-gnu-python3.8-config
lrwxrwxrwx 1 root root      16 Mar 13  2020 /usr/bin/python3-config -> python3.8-config
steve@steve-virtual-machine:/usr/include$ 

Configure seems to be finding python in the right place:

Checking for python... /usr/bin/python
checking for python version... 3.8
checking for python platform... linux
checking for python script directory... ${prefix}/lib/python3.8/site-packages
checking for python extension module directory... ${exec_prefix}/lib/python3.8/site-packages
checking for python3.8... (cached) /usr/bin/python
checking for a version of Python >= '2.1.0'... yes
checking for the distutils Python package... yes
checking for Python include path... -I/usr/include/python3.8
checking for Python library path... -L/usr/lib -lpython3.8
checking for Python site-packages path... /usr/lib/python3/dist-packages
checking python extra libraries... -lcrypt -lpthread -ldl  -lutil -lm -lm
checking python extra linking flags... -Xlinker -export-dynamic -Wl,-O1 -Wl,-Bsymbolic-functions

[steve-cs]

Three recent commits of TB09-023 have been reverted fixing this issue for now. Closing.

[setton]

Thank you @steve-cs for reporting this, and for confirming that it works again.

[steve-cs]

@setton, I could use a reality check. Should GPS build and run with Python3 now or is that still just on the roadmap? If current, I assume that I should be using the gnatcoll-bindings python3 module.

Rather embarrassingly shortly after reporting above that it was working I realized that it did build, but crashed at run time shortly after the splash screen and I never really had a Python3 only system working. I since reverted back to Python2 and things actually run again for me. A few more details are at: steve-cs/gnat-builder#33 if you're curious.

I can stick with Python2, but if you/Adacore have already moved to Python3, I'd like to update my builds to match.

[setton]

Hello @steve-cs - right now we're still with Python 2. We're hard at work on Python3, hopefully it'll land on the main branch in a few weeks.

[steve-cs]

@setton, I'll give it another shot when you're ready. Thanks.