postgresql/config/python.m4
Peter Eisentraut 37f21ed132 Remove support for Python older than 2.6
Supporting very old Python versions is a maintenance burden,
especially with the several variant test files to maintain for Python
<2.6.

Since we have dropped support for older OpenSSL versions in
7b283d0e1d, RHEL 5 is now effectively
desupported, and that was also the only mainstream operating system
still using Python versions before 2.6, so it's a good time to drop
those as well.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/98b69261-298c-13d2-f34d-836fd9c29b21%402ndquadrant.com
2020-01-08 22:47:22 +01:00

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#
# Autoconf macros for configuring the build of Python extension modules
#
# config/python.m4
#
# PGAC_PATH_PYTHON
# ----------------
# Look for Python and set the output variable 'PYTHON' if found,
# fail otherwise.
#
# As the Python 3 transition happens and PEP 394 isn't updated, we
# need to cater to systems that don't have unversioned "python" by
# default. Some systems ship with "python3" by default and perhaps
# have "python" in an optional package. Some systems only have
# "python2" and "python3", in which case it's reasonable to prefer the
# newer version.
AC_DEFUN([PGAC_PATH_PYTHON],
[PGAC_PATH_PROGS(PYTHON, [python python3 python2])
AC_ARG_VAR(PYTHON, [Python program])dnl
if test x"$PYTHON" = x""; then
AC_MSG_ERROR([Python not found])
fi
])
# _PGAC_CHECK_PYTHON_DIRS
# -----------------------
# Determine the name of various directories of a given Python installation,
# as well as the Python version.
AC_DEFUN([_PGAC_CHECK_PYTHON_DIRS],
[AC_REQUIRE([PGAC_PATH_PYTHON])
python_fullversion=`${PYTHON} -c "import sys; print(sys.version)" | sed q`
AC_MSG_NOTICE([using python $python_fullversion])
# python_fullversion is typically n.n.n plus some trailing junk
python_majorversion=`echo "$python_fullversion" | sed '[s/^\([0-9]*\).*/\1/]'`
python_minorversion=`echo "$python_fullversion" | sed '[s/^[0-9]*\.\([0-9]*\).*/\1/]'`
python_version=`echo "$python_fullversion" | sed '[s/^\([0-9]*\.[0-9]*\).*/\1/]'`
# Reject unsupported Python versions as soon as practical.
if test "$python_majorversion" -lt 3 -a "$python_minorversion" -lt 6; then
AC_MSG_ERROR([Python version $python_version is too old (version 2.6 or later is required)])
fi
AC_MSG_CHECKING([for Python distutils module])
if "${PYTHON}" -c 'import distutils' 2>&AS_MESSAGE_LOG_FD
then
AC_MSG_RESULT(yes)
else
AC_MSG_RESULT(no)
AC_MSG_ERROR([distutils module not found])
fi
AC_MSG_CHECKING([Python configuration directory])
python_configdir=`${PYTHON} -c "import distutils.sysconfig; print(' '.join(filter(None,distutils.sysconfig.get_config_vars('LIBPL'))))"`
AC_MSG_RESULT([$python_configdir])
AC_MSG_CHECKING([Python include directories])
python_includespec=`${PYTHON} -c "
import distutils.sysconfig
a = '-I' + distutils.sysconfig.get_python_inc(False)
b = '-I' + distutils.sysconfig.get_python_inc(True)
if a == b:
print(a)
else:
print(a + ' ' + b)"`
if test "$PORTNAME" = win32 ; then
python_includespec=`echo $python_includespec | sed 's,[[\]],/,g'`
fi
AC_MSG_RESULT([$python_includespec])
AC_SUBST(python_majorversion)[]dnl
AC_SUBST(python_version)[]dnl
AC_SUBST(python_includespec)[]dnl
])# _PGAC_CHECK_PYTHON_DIRS
# PGAC_CHECK_PYTHON_EMBED_SETUP
# -----------------------------
#
# Set python_libdir to the path of the directory containing the Python shared
# library. Set python_libspec to the -L/-l linker switches needed to link it.
# Set python_additional_libs to contain any additional linker switches needed
# for subsidiary libraries.
#
# In modern, well-configured Python installations, LIBDIR gives the correct
# directory name and LDLIBRARY is the file name of the shlib. But in older
# installations LDLIBRARY is frequently a useless path fragment, and it's also
# possible that the shlib is in a standard library directory such as /usr/lib
# so that LIBDIR is irrelevant. Also, some packagers put the .so symlink for
# the shlib in ${python_configdir} even though Python itself never does.
# We must also check that what we found is a shared library not a plain
# library, which we do by checking its extension. (We used to rely on
# Py_ENABLE_SHARED, but that only tells us that a shlib exists, not that
# we found it.)
AC_DEFUN([PGAC_CHECK_PYTHON_EMBED_SETUP],
[AC_REQUIRE([_PGAC_CHECK_PYTHON_DIRS])
AC_MSG_CHECKING([how to link an embedded Python application])
python_libdir=`${PYTHON} -c "import distutils.sysconfig; print(' '.join(filter(None,distutils.sysconfig.get_config_vars('LIBDIR'))))"`
python_ldlibrary=`${PYTHON} -c "import distutils.sysconfig; print(' '.join(filter(None,distutils.sysconfig.get_config_vars('LDLIBRARY'))))"`
# If LDLIBRARY exists and has a shlib extension, use it verbatim.
ldlibrary=`echo "${python_ldlibrary}" | sed -e 's/\.so$//' -e 's/\.dll$//' -e 's/\.dylib$//' -e 's/\.sl$//'`
if test -e "${python_libdir}/${python_ldlibrary}" -a x"${python_ldlibrary}" != x"${ldlibrary}"
then
ldlibrary=`echo "${ldlibrary}" | sed "s/^lib//"`
found_shlib=1
else
# Otherwise, guess the base name of the shlib.
# LDVERSION was added in Python 3.2, before that use VERSION,
# or failing that, $python_version from _PGAC_CHECK_PYTHON_DIRS.
python_ldversion=`${PYTHON} -c "import distutils.sysconfig; print(' '.join(filter(None,distutils.sysconfig.get_config_vars('LDVERSION'))))"`
if test x"${python_ldversion}" != x""; then
ldlibrary="python${python_ldversion}"
else
python_version_var=`${PYTHON} -c "import distutils.sysconfig; print(' '.join(filter(None,distutils.sysconfig.get_config_vars('VERSION'))))"`
if test x"${python_version_var}" != x""; then
ldlibrary="python${python_version_var}"
else
ldlibrary="python${python_version}"
fi
fi
# Search for a likely-looking file.
found_shlib=0
for d in "${python_libdir}" "${python_configdir}" /usr/lib64 /usr/lib
do
# We don't know the platform DLSUFFIX here, so check 'em all.
for e in .so .dll .dylib .sl; do
if test -e "$d/lib${ldlibrary}$e"; then
python_libdir="$d"
found_shlib=1
break 2
fi
done
done
# Some platforms (OpenBSD) require us to accept a bare versioned shlib
# (".so.n.n") as well. However, check this only after failing to find
# ".so" anywhere, because yet other platforms (Debian) put the .so
# symlink in a different directory from the underlying versioned shlib.
if test "$found_shlib" != 1; then
for d in "${python_libdir}" "${python_configdir}" /usr/lib64 /usr/lib
do
for f in "$d/lib${ldlibrary}.so."* ; do
if test -e "$f"; then
python_libdir="$d"
found_shlib=1
break 2
fi
done
done
fi
# As usual, Windows has its own ideas. Possible default library
# locations include c:/Windows/System32 and (for Cygwin) /usr/bin,
# and the "lib" prefix might not be there.
if test "$found_shlib" != 1 -a \( "$PORTNAME" = win32 -o "$PORTNAME" = cygwin \); then
for d in "${python_libdir}" "${python_configdir}" c:/Windows/System32 /usr/bin
do
for f in "$d/lib${ldlibrary}.dll" "$d/${ldlibrary}.dll" ; do
if test -e "$f"; then
python_libdir="$d"
found_shlib=1
break 2
fi
done
done
fi
fi
if test "$found_shlib" != 1; then
AC_MSG_ERROR([could not find shared library for Python
You might have to rebuild your Python installation. Refer to the
documentation for details. Use --without-python to disable building
PL/Python.])
fi
python_libspec="-L${python_libdir} -l${ldlibrary}"
python_additional_libs=`${PYTHON} -c "import distutils.sysconfig; print(' '.join(filter(None,distutils.sysconfig.get_config_vars('LIBS','LIBC','LIBM','BASEMODLIBS'))))"`
AC_MSG_RESULT([${python_libspec} ${python_additional_libs}])
AC_SUBST(python_libdir)[]dnl
AC_SUBST(python_libspec)[]dnl
AC_SUBST(python_additional_libs)[]dnl
])# PGAC_CHECK_PYTHON_EMBED_SETUP