Revert PR #589

* Revert "Release Notes for PYTHON=python3"
  commit 2612b47c3f.

* Revert "Remove Python build dependency when LINKER_USE_RPATH=ORIGIN"
  commit f4c474eb77.

configure/CONFIG_BASE

@@ -54,7 +54,8 @@ CONVERTRELEASE   = $(PERL) $(call FIND_TOOL,convertRelease.pl)
 FILTERMAKEFLAGS  = $(PERL) $(call FIND_TOOL,filterMakeflags.pl)
 FULLPATHNAME     = $(PERL) $(TOOLS)/fullPathName.pl
 GENVERSIONHEADER = $(PERL) $(TOOLS)/genVersionHeader.pl $(QUIET_FLAG) $(QUESTION_FLAG)
-MAKERPATH        = $(PERL) $(TOOLS)/makeRPath.pl
+
+MAKERPATH = $(PYTHON) $(TOOLS)/makeRPath.py
 
 #---------------------------------------------------------------
 # tools for installing libraries and products

configure/CONFIG_COMMON

@@ -34,11 +34,11 @@ CROSS2 = $(CROSS_COMPILER_TARGET_ARCHS$(filter-out 1,$(words $(filter $(EPICS_HO
 BUILD_ARCHS = $(EPICS_HOST_ARCH) $(CROSS1) $(CROSS2)
 
 #-------------------------------------------------------
-# Defaults for Perl and Python assume they're on $PATH.
+# Default for perl if it's on the PATH,
-# Python (now python3) is only needed by developers, when building docs.
+# otherwise override this in os/CONFIG_SITE.<host_arch>.Common
-# Override these in os/CONFIG_SITE.<host_arch>.Common or CONFIG_SITE.local
 PERL = perl -CSD
-PYTHON = python3
+
+PYTHON = python
 
 #-------------------------------------------------------
 # Check configure/RELEASE file for consistency

documentation/RELEASE_NOTES.md

@@ -22,24 +22,6 @@ should also be read to understand what has changed since earlier releases:
 
 ## Changes made on the 7.0 branch since 7.0.8.1
 
-### Build system `$(PYTHON)` default changed
-
-The default value of the build system's `$(PYTHON)` variable has changed from
-`python` to `python3`, in line with many recent OS installations' removal of
-the `python` binary after Python 2 support ended.
-This change may affect EPICS support modules which run Python scripts at
-build-time that haven't yet been converted to Python 3.
-If needed, the value can be overridden in a `configure/CONFIG_SITE.local` file,
-either in Base or in the specific module.
-
-This variable was added in EPICS 7.0.3.1 and only used by Base when configured
-with `LINKER_USE_RPATH=ORIGIN`.
-That configuration now runs a Perl translation of the original script, so
-Python is not required to build Base.
-
-EPICS developers working on documentation may need to point `PYTHON` to a
-Pythons venv that has the additional packages needed to run Sphinx.
-
 ### Post monitors from compress record when it's reset
 
 Writing into a compress record's `RES` field now posts a monitor event instead

src/tools/Makefile

@@ -37,7 +37,6 @@ PERL_SCRIPTS += fullPathName.pl
 PERL_SCRIPTS += installEpics.pl
 PERL_SCRIPTS += makeAPIheader.pl
 PERL_SCRIPTS += makeMakefile.pl
-PERL_SCRIPTS += makeRPath.pl
 PERL_SCRIPTS += makeTestfile.pl
 PERL_SCRIPTS += mkmf.pl
 PERL_SCRIPTS += munch.pl
@@ -50,13 +49,14 @@ PERL_SCRIPTS += testFailures.pl
 PERL_SCRIPTS += useManifestTool.pl
 PERL_SCRIPTS += genVersionHeader.pl
 
+PERL_SCRIPTS += makeRPath.py
+
 HTMLS = style.css
 HTMLS += EPICS/Getopts.html
 HTMLS += EPICS/Path.html
 HTMLS += EPICS/Readfile.html
 HTMLS += fullPathName.html
 HTMLS += makeAPIheader.html
-HTMLS += makeRPath.html
 HTMLS += munch.html
 HTMLS += podToHtml.html
 HTMLS += podToMD.html

src/tools/makeRPath.pl

@@ -1,135 +0,0 @@
-#!/usr/bin/env perl
-#*************************************************************************
-# SPDX-License-Identifier: EPICS
-# EPICS BASE is distributed subject to a Software License Agreement found
-# in file LICENSE that is included with this distribution.
-#*************************************************************************
-
-use strict;
-use warnings;
-
-use Getopt::Long;
-use Cwd qw(abs_path getcwd);
-use File::Spec;
-use File::Basename;
-use Pod::Usage;
-
-# Example:
-#   target to be installed as: /build/bin/blah
-#   post-install will copy as: /install/bin/blah
-#
-# Need to link against:
-#   /install/lib/libA.so
-#   /build/lib/libB.so
-#   /other/lib/libC.so
-#
-# Want final result to be:
-#   -rpath $ORIGIN/../lib -rpath /other/lib \
-#   -rpath-link /build/lib -rpath-link /install/lib
-
-warn "[" . join(' ', $0, @ARGV) . "]\n"
-    if $ENV{EPICS_DEBUG_RPATH} && $ENV{EPICS_DEBUG_RPATH} eq 'YES';
-
-# Defaults for command-line arguments
-my $final = getcwd();
-my $root = '';
-my $origin = '$ORIGIN';
-my $help = 0;
-
-# Parse command-line arguments
-GetOptions(
-    'final|F=s'  => \$final,
-    'root|R=s'   => \$root,
-    'origin|O=s' => \$origin,
-    'help|h'     => \$help,
-) or pod2usage(
-    -exitval => 2,
-    -verbose => 1,
-    -noperldoc => 1,
-);
-
-# Display help message if requested
-pod2usage(
-    -exitval => 1,
-    -verbose => 2,
-    -noperldoc => 1,
-) if $help;
-
-# Convert paths to absolute
-$final = abs_path($final);
-my @roots = map { abs_path($_) } grep { length($_) } split(/:/, $root);
-
-# Determine the root containing the final location
-my $froot;
-foreach my $root (@roots) {
-    my $frel = File::Spec->abs2rel($final, $root);
-    if ($frel !~ /^\.\./) {
-        $froot = $root;
-        last;
-    }
-}
-
-if (!defined $froot) {
-    warn "makeRPath: Final location $final\n" .
-         "Not under any of: @roots\n";
-    @roots = ();  # Skip $ORIGIN handling below
-}
-
-# Prepare output
-my (@output, %output);
-foreach my $path (@ARGV) {
-    $path = abs_path($path);
-    foreach my $root (@roots) {
-        my $rrel = File::Spec->abs2rel($path, $root);
-        if ($rrel !~ /^\.\./) {
-            # Add rpath-link for internal use by 'ld'
-            my $opt = "-Wl,-rpath-link,$path";
-            push @output, $opt unless $output{$opt}++;
-
-            # Calculate relative path
-            my $rel_path = File::Spec->abs2rel($rrel, $final);
-            my $opath = File::Spec->catfile($origin, $rel_path);
-            $opt = "-Wl,-rpath,$opath";
-            push @output, $opt unless $output{$opt}++;
-            last;
-        }
-    }
-}
-
-# Print the output
-print join(' ', @output), "\n";
-
-__END__
-
-=head1 NAME
-
-makeRPath.pl - Compute and output -rpath entries for given paths
-
-=head1 SYNOPSIS
-
-makeRPath.pl [options] [path ...]
-
-=head1 OPTIONS
-
-    -h, --help      Display detailed help and exit
-    -F, --final     Final install location for ELF file
-    -R, --root      Root(s) of relocatable tree, separated by ':'
-    -O, --origin    Origin path (default: '$ORIGIN')
-
-=head1 DESCRIPTION
-
-Computes and outputs -rpath entries for each of the given paths.
-Paths under C<--root> will be computed as relative to C<--final>.
-
-=head1 EXAMPLE
-
-A library to be placed in C</build/lib> and linked against libraries in
-C</build/lib>, C</build/module/lib>, and C</other/lib> would pass
-
-  makeRPath.pl -F /build/lib -R /build /build/lib /build/module/lib /other/lib
-
-which generates
-
-  -Wl,-rpath,$ORIGIN/. -Wl,-rpath,$ORIGIN/../module/lib -Wl,-rpath,/other/lib
-
-=cut

src/tools/makeRPath.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python
+#*************************************************************************
+# SPDX-License-Identifier: EPICS
+# EPICS BASE is distributed subject to a Software License Agreement found
+# in file LICENSE that is included with this distribution.
+#*************************************************************************
+
+from __future__ import print_function
+
+import sys
+import os
+from collections import OrderedDict # used as OrderedSet
+
+from argparse import ArgumentParser
+
+if os.environ.get('EPICS_DEBUG_RPATH','')=='YES':
+    sys.stderr.write('%s'%sys.argv)
+
+P = ArgumentParser(description='''Compute and output -rpath entries for each of the given paths.
+  Paths under --root will be computed as relative to --final .''',
+epilog='''
+eg. A library to be placed in /build/lib and linked against libraries in
+'/build/lib', '/build/module/lib', and '/other/lib' would pass:
+
+ "makeRPath.py -F /build/lib -R /build /build/lib /build/module/lib /other/lib"
+which prints "-Wl,-rpath,$ORIGIN/. -Wl,-rpath,$ORIGIN/../module/lib -Wl,-rpath,/other/lib"
+''')
+P.add_argument('-F','--final',default=os.getcwd(), help='Final install location for ELF file')
+P.add_argument('-R','--root',default='', help='Root(s) of relocatable tree.  Separate with :')
+P.add_argument('-O', '--origin', default='$ORIGIN')
+P.add_argument('path', nargs='*')
+args = P.parse_args()
+
+# eg.
+# target to be installed as: /build/bin/blah
+#
+# post-install will copy as:  /install/bin/blah
+#
+# Need to link against:
+#   /install/lib/libA.so
+#   /build/lib/libB.so
+#   /other/lib/libC.so
+#
+# Want final result to be:
+#  -rpath $ORIGIN/../lib -rpath /other/lib \
+#  -rpath-link /build/lib -rpath-link /install/lib
+
+fdir = os.path.abspath(args.final)
+roots = [os.path.abspath(root) for root in args.root.split(':') if len(root)]
+
+# find the root which contains the final location
+froot = None
+for root in roots:
+    frel = os.path.relpath(fdir, root)
+    if not frel.startswith('..'):
+        # final dir is under this root
+        froot = root
+        break
+
+if froot is None:
+    sys.stderr.write("makeRPath: Final location %s\nNot under any of: %s\n"%(fdir, roots))
+    # skip $ORIGIN handling below...
+    roots = []
+
+output = OrderedDict()
+for path in args.path:
+    path = os.path.abspath(path)
+
+    for root in roots:
+        rrel = os.path.relpath(path, root)
+        if not rrel.startswith('..'):
+            # path is under this root
+
+            # some older binutils don't seem to handle $ORIGIN correctly
+            # when locating dependencies of libraries.  So also provide
+            # the absolute path for internal use by 'ld' only.
+            output['-Wl,-rpath-link,'+path] = True
+
+            # frel is final location relative to enclosing root
+            # rrel is target location relative to enclosing root
+            path = os.path.relpath(rrel, frel)
+            break
+
+    output['-Wl,-rpath,'+os.path.join(args.origin, path)] = True
+
+print(' '.join(output))