commit af29047480cacafaed697cb2a1fb24c5143078a8 Author: John Dennis Date: Sat Jul 7 10:59:32 2018 -0400 Configure should search for versioned Python interpreter. Following the guidelines in Python PEP 394 with regards to the python command on UNIX like systems preference should be given to explicitly versioned command interpreter as opposed to unversioned and that an unversioned python command should (but might not) refer to Python2. Also in some environments unversioned Python interpreters (e.g. /usr/bin/python) do not even exist, onlyh their explicitly versioned variants are (e.g. /usr/bin/python2 and /usr/bin/python3). Therefore the AC_CHECK_PROGS directive in configure.ac should not rely exclusively on an unversioned Python interpreter as it does not, rather it should search in priority order. First for python3, then for an unversionsed python because some distributions have already moved the default unversioned python to python3, and then finally search for python2. In the scenario where unversioned python is still pointing to python2 it's equivalent to selecting the last prority option of python2, but if unversioned python is pointing to python3 you get instead. The net result is always preferring python3 but gracefully falling back to python2 not matter how the environment exports it's Python. If AC_CHECK_PROGS for python does not check for the versioned variants the build fails in environments that only have versioned variants with this error: configure: error: Python must be installed to compile lasso License: MIT Signed-off-by: John Dennis diff --git a/configure.ac b/configure.ac index 898468e6..74766972 100644 --- a/configure.ac +++ b/configure.ac @@ -131,7 +131,7 @@ dnl AC_CHECK_PROGS(JAR, fastjar jar) AC_CHECK_PROGS(PERL, perl) AC_CHECK_PROGS(PHP5, php5 php) AC_CHECK_PROGS(PHP5_CONFIG, php-config5 php-config) -AC_CHECK_PROGS(PYTHON, python) +AC_CHECK_PROGS(PYTHON, python3 python python2) AC_CHECK_PROGS(SWIG, swig) dnl Make sure we have an ANSI compiler