THRIFT-5087 test/test.py fails with "AssertionError: Python 3.3 or later is required for proper operation."
Client: Python
Patch: Jano Svitok

This closes #2055

THRIFT-5087: Show features log, check log presence
THRIFT-5087: Revert/Improve PR1995 (commit f8b004081da)

Make the condition work both
a) when both python2 and python3 are installed
b) when only python3 is installed

Check also python 3.8 when searching for 3.x
diff --git a/configure.ac b/configure.ac
index 99c3c9c..35f43ee 100755
--- a/configure.ac
+++ b/configure.ac
@@ -306,11 +306,15 @@
 have_py3="no"
 AX_THRIFT_LIB(py3, [Py3], yes)
 if test "$with_py3" = "yes"; then
-  if $PYTHON --version 2>&1 | grep -q "Python 3"; then
-    AC_PATH_PROGS([PYTHON3], [python3 python3.7 python37 python3.6 python36 python3.5 python35 python3.4 python34])
+  # if $PYTHON is 2.x then search for python 3. otherwise, $PYTHON is already 3.x
+  if $PYTHON --version 2>&1 | grep -q "Python 2"; then
+    AC_PATH_PROGS([PYTHON3], [python3 python3.8 python38 python3.7 python37 python3.6 python36 python3.5 python35 python3.4 python34])
     if test -n "$PYTHON3"; then
       have_py3="yes"
     fi
+  elif $PYTHON --version 2>&1 | grep -q "Python 3"; then
+    have_py3="yes"
+    PYTHON3=$PYTHON
   fi
 fi
 AM_CONDITIONAL(WITH_PY3, [test "$have_py3" = "yes"])