Re: recent 'lib.pm' change => dual-life lib.pm

Message-ID: <483BF56D.2020803@sneakemail.com>

p4raw-id: //depot/perl@33973

1 files changed, 56 insertions, 3 deletions

diff --git a/lib/lib_pm.PL b/lib/lib_pm.PL
index bb2f7ccfcd..c12570828f 100644
--- a/lib/lib_pm.PL
+++ b/lib/lib_pm.PL
@@ -13,10 +13,37 @@ my $Config_archname;
 my $Config_version;
 my $Config_inc_version_list;
 
-# Expand the variables only if explicitly requested because
-# otherwise relocating Perl becomes much harder.
+# Expand the variables only if explicitly requested
+# or if a previously installed lib.pm does this, too
+# because otherwise relocating Perl becomes much harder.
 
+my $expand_config_vars = 0;
 if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) {
+  $expand_config_vars = 1;
+}
+elsif (exists $ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) {
+  $expand_config_vars = 0;
+}
+else {
+  eval <<'HERE';
+  require lib;
+  my $lib_file = $INC{"lib.pm"};
+  open my $fh, '<', $lib_file
+    or die "Could not open file '$lib_file' for reading: $!";
+  my $ConfigRegex = qr/(?:use|require)\s+Config(?:\s+|;)/;
+  while (defined($_ = <$fh>)) {
+    # crude heuristics to check that we were using Config
+    if (/^\s*$ConfigRegex/ || /^\s*eval.*$ConfigRegex/) {
+      $expand_config_vars = 0;
+      last;
+    }
+  }
+  $expand_config_vars = 1;
+HERE
+  $expand_config_vars = 0 if $@;
+}
+
+if ($expand_config_vars) {
     $useConfig = '';
     $Config_archname = qq('$Config{archname}');
     $Config_version  = qq('$Config{version}');
@@ -58,7 +85,7 @@ my \@inc_version_list = $Config_inc_version_list;
 print OUT <<'!NO!SUBS!';
 
 our @ORIG_INC = @INC;	# take a handy copy of 'original' value
-our $VERSION = '0.56';
+our $VERSION = '0.57';
 my $Is_MacOS = $^O eq 'MacOS';
 my $Mac_FS;
 if ($Is_MacOS) {
@@ -244,14 +271,40 @@ paths, as it does now for Mac OS (where Unix-style or Mac-style paths
 work, and Unix-style paths are converted properly to Mac-style paths
 before being added to @INC).
 
+If you try to add a file to @INC as follows:
+
+  use lib 'this_is_a_file.txt';
+
+C<lib> will warn about this. The sole exceptions are files with the
+C<.par> extension which are intended to be used as libraries.
+
 =head1 SEE ALSO
 
 FindBin - optional module which deals with paths relative to the source file.
 
+PAR - optional module which can treat C<.par> files as Perl libraries.
+
 =head1 AUTHOR
 
 Tim Bunce, 2nd June 1995.
 
+C<lib> is maintained by the perl5-porters. Please direct
+any questions to the canonical mailing list. Anything that
+is applicable to the CPAN release can be sent to its maintainer,
+though.
+
+Maintainer: The Perl5-Porters <perl5-porters@perl.org>
+
+Maintainer of the CPAN release: Steffen Mueller <smueller@cpan.org>
+
+=head1 COPYRIGHT AND LICENSE
+
+This package has been part of the perl core since perl 5.001.
+It has been released separately to CPAN so older installations
+can benefit from bug fixes.
+
+This package has the same copyright and license as the perl core.
+
 =cut
 !NO!SUBS!