installation into cpython 3.8 venv fails

[oberstet]

not sure: is python 3.8 and venv supported? the installer fails for me for a cpython 3.8 based venv:

(cpy381_1) ubuntu@markets:~/Plone-5.0.4-UnifiedInstaller$ ./install.sh --with-python=`which python3` standalone

Testing /home/ubuntu/cpy381_1/bin/python3 for Zope/Plone requirements....
  File "helper_scripts/checkPython.py", line 15
    print _("Failed: Python version must be 2.7.x.")
          ^
SyntaxError: invalid syntax

/home/ubuntu/cpy381_1/bin/python3 does not meet the requirements for Zope/Plone.

Please do one of the following:
1) Install python2.7 as a system dev package\;
2) Use --with-python=... option to point the installer to a useable python\; or
3) Use the --build-python option to tell the installer to build Python.

(cpy381_1) ubuntu@markets:~/Plone-5.0.4-UnifiedInstaller$ which python3
/home/ubuntu/cpy381_1/bin/python3
(cpy381_1) ubuntu@markets:~/Plone-5.0.4-UnifiedInstaller$ ll `which python3`
lrwxrwxrwx 1 ubuntu ubuntu 31 Feb  9 09:38 /home/ubuntu/cpy381_1/bin/python3 -> /home/ubuntu/cpy381/bin/python3*
(cpy381_1) ubuntu@markets:~/Plone-5.0.4-UnifiedInstaller$ python3 -V
Python 3.8.1
(cpy381_1) ubuntu@markets:~/Plone-5.0.4-UnifiedInstaller$ 

pip install plone runs happily without any error or warning in that exact venv

[oberstet]

I also tried master .. no luck:

(cpy381_1) ubuntu@markets:~/scm/3rdparty/Installers-UnifiedInstaller$ ./install.sh standalone --target=${HOME}/Plone--with-python=`which python3`

The install script directory must contain
/home/ubuntu/scm/3rdparty/Installers-UnifiedInstaller/packages and /home/ubuntu/scm/3rdparty/Installers-UnifiedInstaller/helper_scripts subdirectories.

(cpy381_1) ubuntu@markets:~/scm/3rdparty/Installers-UnifiedInstaller$ git log -n1
commit 97e668911b5945a343907ecc7d9386c3ed9022a0 (HEAD -> master, tag: 5.2.1-r2, origin/master, origin/HEAD)
Author: T. Kim Nguyen <tkn@alumni.uwaterloo.ca>
Date:   Tue Jan 21 11:24:29 2020 -0600

    include PloneHotfix20200121
(cpy381_1) ubuntu@markets:~/scm/3rdparty/Installers-UnifiedInstaller$ git remote -v
origin  https://github.com/plone/Installers-UnifiedInstaller.git (fetch)
origin  https://github.com/plone/Installers-UnifiedInstaller.git (push)
(cpy381_1) ubuntu@markets:~/scm/3rdparty/Installers-UnifiedInstaller$ 

[smcmahon]

It looks like you're installing Plone 5.0.4. Python 3.x is only supported in Plone 5.1+.

[oberstet]

ah, ok I see, thanks for your hint and sorry for the noise!