command not found errors from configure

[Marc Culler]

It is disturbing when one sees "command not found" errors in a configure script.  That is what happens with 10.4.beta5.  After tracing it down I found that they are coming from lines like:

    if "${PYTHON_FOR_VENV}" -c "import sys; sys.exit(sys.version_info.minor < 11)"

then :

The variable PYTHON_FOR_VENV is set with the command:

if test x$sage_spkg_install_python3 = xno
then :

        PYTHON_FOR_VENV="$ac_cv_path_PYTHON3"

But I think that if sage_spkg_install_python3 has the value yes then PYTHON_FOR_VENV is not assigned a value, causing the errors when configure is run.

I have not determined what the collateral damage of this is.  But it seems to me that there should be a default value for  PYTHON_FOR_VENV.

- Marc

[Marc Culler]

Oh.  And I think the default value should probably  be set with:

PYTHON_FOR_VENV=/usr/bin/false

- Marc

[Matthias Koeppe]

Fix in https://github.com/sagemath/sage/pull/37959