Add explicit test for Python >= v3.7 in configure

Open MPI's Python scripts have been tested with v3.6 and work, but the
pympistandard module requires Python >= v3.7.  Hence, the minimum
Python version required is v3.7.

* Add an explicit test to early in configure.ac for Python >= v3.7
* Remove a test later in configure for Python >= v3.6 for generating
  the Fortran bindings
  * Since we will now always have Python >= v3.7, remove all the
    conditional logic for generating the Fortran bindings
* Update several places in the docs to note that Open MPI now requires
  Python >= v3.7 to build
  * Maintain the minimum required Python version in VERSION (along
    with other external dependency minimum versions)

Signed-off-by: Jeff Squyres <[email protected]>

Author: jsquyres

VERSION

@@ -33,6 +33,7 @@ automake_min_version=1.13.4
 autoconf_min_version=2.69.0
 libtool_min_version=2.4.2
 flex_min_version=2.5.4
+python_min_version=3.7
 
 # greek is generally used for alpha or beta release tags.  If it is
 # non-empty, it will be appended to the version number.  It does not

config/ompi_configure_options.m4

@@ -252,13 +252,4 @@ else
    ompi_want_ompio=1
 fi
 AM_CONDITIONAL(OMPI_OMPIO_SUPPORT, test "$ompi_want_ompio" = "1")
-
-# If the binding source files don't exist, then we need Python to generate them
-AM_PATH_PYTHON([3.6],,[:])
-binding_file="${srcdir}/ompi/mpi/c/ompi_send.c"
-AS_IF([! test -e "$binding_file" && test "$PYTHON" = ":"],
-      [AC_MSG_ERROR([Open MPI requires Python >=3.6 for generating the bindings. Aborting])])
-AM_CONDITIONAL(OMPI_GENERATE_BINDINGS,[test "$PYTHON" != ":"])
-
 ])dnl
-

configure.ac

@@ -77,6 +77,7 @@ OPAL_MAKEDIST_DISABLE=""
 # Start it up
 #
 
+. $srcdir/VERSION
 OPAL_CONFIGURE_SETUP
 opal_show_title "Configuring project_name_long"
 opal_show_subtitle "Prerequisites"
@@ -85,7 +86,10 @@ AC_PROG_SED
 
 AC_CHECK_PROG([PERL],[perl],[perl],[no])
 AS_IF([test "X$PERL" = "Xno"],
-      [AC_MSG_ERROR(["Open MPI requires perl. Aborting"])])
+      [AC_MSG_ERROR([Open MPI requires perl to build. Aborting.])])
+
+AM_PATH_PYTHON([$python_min_version],[],
+               [AC_MSG_ERROR([Open MPI requires Python >=$python_min_version to build. Aborting.])])
 
 #
 # Setup some things that must be done before AM-INIT-AUTOMAKE
@@ -153,7 +157,6 @@ OPAL_SAVE_VERSION([OPAL], [Open Portable Access Layer], [$srcdir/VERSION],
 
 # Get shared library version numbers
 
-. $srcdir/VERSION
 m4_ifdef([project_ompi],
          [AC_SUBST(libmpi_so_version)
           AC_SUBST(libmpi_mpifh_so_version)

docs/conf.py

@@ -101,6 +101,7 @@ def get_tarball_version(path, expr):
 autoconf_min_version = f"{ompi_data['autoconf_min_version']}"
 libtool_min_version = f"{ompi_data['libtool_min_version']}"
 flex_min_version = f"{ompi_data['flex_min_version']}"
+python_min_version = f"{ompi_data['python_min_version']}"
 mpi_standard_major_version = f"{ompi_data['mpi_standard_version']}"
 mpi_standard_minor_version = f"{ompi_data['mpi_standard_subversion']}"
 
@@ -304,6 +305,7 @@ def _doit(topdir):
 .. |autoconf_min_version| replace:: {autoconf_min_version}
 .. |libtool_min_version| replace:: {libtool_min_version}
 .. |flex_min_version| replace:: {flex_min_version}
+.. |python_min_version| replace:: {python_min_version}
 .. |mpi_standard_version| replace:: {mpi_standard_major_version}.{mpi_standard_minor_version}
 .. |mpi_standard_major_version| replace:: {mpi_standard_major_version}
 .. |mpi_standard_minor_version| replace:: {mpi_standard_minor_version}

docs/developers/prerequisites.rst

@@ -50,11 +50,25 @@ more detail.
 Python
 ------
 
-Python >= v3.6 is required for generating the Fortran bindings, which
-is necessary if you build Open MPI from a Git clone.
+Python >= |python_min_version| is required for several tasks during
+the Open MPI build, such as (but not limited to):
 
-Python is also required for running Sphinx to generate the docs, too
-(:ref:`see below <developers-requirements-sphinx-label>`).
+* Generating the Fortran bindings
+
+* Generating Fortran constants and compiler-specific symbols
+
+* Generating the "show help" messages
+
+* Generating bindings in the MPI man pages (from the pympistandrd
+  module)
+
+* Building the Open MPI documentation and man pages
+
+All of these are necessary are necessary when building from a Git
+clone.  Most of these can be accomplished with core Python; only
+building the full Open MPI documentation and man pages requires
+additional packages (:ref:`see below
+<developers-requirements-sphinx-label>`).
 
 Perl
 ----

docs/installing-open-mpi/quickstart.rst

@@ -62,7 +62,8 @@ Download the Open MPI source code from `the main Open MPI web site
              They are **not** official Open MPI releases.
 
 Open MPI uses a traditional ``configure`` script paired with ``make``
-to build.  Typical installs can be of the pattern:
+to build.  Open MPI uses both Perl and Python >= |python_min_version|
+as part of its build process.  Typical installs can be of the pattern:
 
 .. code-block:: sh
 

docs/installing-open-mpi/supported-systems.rst

@@ -23,6 +23,15 @@ Open MPI to compile and run properly.  The biggest obstacle is
 typically the assembly language, but that's fairly modular and we're
 happy to provide information about how to port it to new platforms.
 
+Open MPI uses both Perl and Python >= |python_min_version| while
+building.  You will need to have both of these available to build Open
+MPI from a source tarball.
+
+.. note:: The Open MPI community is slowly converting its Perl scripts
+          to Python; it is expected (hoped) that we'll someday have no
+          more Perl in the build process for official distribution
+          tarballs or Git clones.
+
 It should be noted that we are quite open to accepting patches for
 operating systems that we do not currently support.  If we do not have
 systems to test these on, we probably will only claim to

docs/release-notes/changelog/v6.0.x.rst

@@ -9,5 +9,12 @@ Open MPI version v6.0.0
 :Date: ...fill me in...
 
 - Open MPI now requires a C11-compliant compiler to build.
+
+- Open MPI now requires Python >= |python_min_version| to build.
+
+  - Open MPI has always required Perl to build; our Perl scripts are
+    slowly being converted to Python.
+
 - Removed ROMIO package.
+
 - Added MPI-4.1 ``MPI_Status_*`` functions.

ompi/mpi/c/Makefile.am

@@ -539,7 +539,7 @@ libmpi_c_noprofile_la_SOURCES = $(interface_profile_sources)
 libmpi_c_noprofile_la_CPPFLAGS = -DOMPI_BUILD_MPI_PROFILING=0
 
 # ABI generation rules
-if OMPI_GENERATE_BINDINGS
+
 %_generated.c: %.c.in
 	$(OMPI_V_GEN) $(PYTHON) $(top_srcdir)/ompi/mpi/bindings/bindings.py \
 	    --builddir $(abs_top_builddir) \
@@ -550,6 +550,5 @@ if OMPI_GENERATE_BINDINGS
 	    ompi \
 	    $<
 
-endif
 # Delete generated files on maintainer-clean
 MAINTAINERCLEANFILES = *_generated.c

ompi/mpi/fortran/use-mpi-f08/Makefile.am

@@ -431,8 +431,6 @@ lib@OMPI_LIBMPI_NAME@_usempif08_profile_la_FCFLAGS = \
 # *.in template.
 #
 
-if OMPI_GENERATE_BINDINGS
-
 include Makefile.prototype_files
 template_files =${prototype_files:%=$(abs_top_srcdir)/ompi/mpi/fortran/use-mpi-f08/%}
 
@@ -453,8 +451,6 @@ api_f08_generated.F90: $(template_files)
 
 EXTRA_DIST = $(prototype_files)
 
-endif
-
 # Delete generated file on maintainer-clean
 MAINTAINERCLEANFILES = api_f08_generated.F90