On the eclair cluster
vahi@eclair-sub-01 pegasus]$ python3 --version
Python 3.6.8

[vahi@eclair-sub-01 pegasus]$ ls -lht /usr/bin/python3*
-rwxr-xr-x 1 root root 7.6K Nov 15 01:24 /usr/bin/python3.9
-rwxr-xr-x 1 root root 7.6K Nov 15 00:56 /usr/bin/python3.11
lrwxrwxrwx. 1 root root 25 Mar 27 2023 /usr/bin/python3 -> /etc/alternatives/python3
lrwxrwxrwx 1 root root 31 Oct 9 2021 /usr/bin/python3.6 -> /usr/libexec/platform-python3.6
lrwxrwxrwx 1 root root 32 Oct 9 2021 /usr/bin/python3.6m -> /usr/libexec/platform-python3.6m
[vahi@eclair-sub-01 pegasus]$

With python3.6 pegasus build fails as expected, since future feature annotations is not defined.
compile-externals:
[exec] Building python-dateutil-2.8.1.tar.gz
[exec] Traceback (most recent call last):
[exec] File "setup.py", line 56, in <module>
[exec] "test": Unsupported
[exec] File "/usr/lib/python3.6/site-packages/setuptools/_init_.py", line 129, in setup
[exec] return distutils.core.setup(**attrs)
[exec] File "/usr/lib64/python3.6/distutils/core.py", line 108, in setup
[exec] _setup_distribution = dist = klass(attrs)
[exec] File "/usr/lib/python3.6/site-packages/setuptools/dist.py", line 370, in _init_
[exec] k: v for k, v in attrs.items()
[exec] File "/usr/lib64/python3.6/distutils/dist.py", line 281, in _init_
[exec] self.finalize_options()
[exec] File "/usr/lib/python3.6/site-packages/setuptools/dist.py", line 529, in finalize_options
[exec] ep.load()(self, ep.name, value)
[exec] File "/usr/lib/python3.6/site-packages/pkg_resources/_init_.py", line 2318, in load
[exec] return self.resolve()
[exec] File "/usr/lib/python3.6/site-packages/pkg_resources/_init_.py", line 2324, in resolve
[exec] module = _import_(self.module_name, fromlist=['__name__'], level=0)
[exec] File "/nas/home/vahi/software/src/pegasus/src/externals/python-dateutil-2.8.1/.eggs/setuptools_scm-8.0.4-py3.6.egg/setuptools_scm/_init_.py", line 5
[exec] from _future_ import annotations
[exec] ^
[exec] SyntaxError: future feature annotations is not defined

However, if i create an alias to the 3.9 install
[vahi@eclair-sub-01 pegasus]$ alias python3=python3.9
[vahi@eclair-sub-01 pegasus]$ which python3
alias python3='python3.9'
/usr/bin/python3.9
[vahi@eclair-sub-01 pegasus]$ python3 --version
Python 3.9.18

the build still detects 3.6 somehow
[vahi@eclair-sub-01 pegasus]$ python3 --version
Python 3.9.18
[vahi@eclair-sub-01 pegasus]$ ant dist
Unable to locate tools.jar. Expected to find it in /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.392.b08-4.el8.x86_64/lib/tools.jar
Buildfile: /nas/home/vahi/software/src/pegasus/build.xml
[echo] Pegasus Version: 5.0.7dev
[echo] JAVA TARGET is 1.8
[echo] JAVA SOURCE is 1.8
[echo] Running in CI false
[echo] Build timestamp: 20231207233136Z
[echo] Architecture: x86_64_almalinux_8
[echo] OSID: almalinux8
[echo] Library subdir: lib64
[echo] Python: /usr/bin/python3
[echo] Python library subdir: lib64/python3.6/site-packages

set-git-hash: