Update Porting/cmpVERSION.pl to use git

Update Porting/cmpVERSION.pl to take a directory and a git tag,
rather than two directories, as suggested in perltodo.

1 files changed, 82 insertions, 51 deletions

diff --git a/Porting/cmpVERSION.pl b/Porting/cmpVERSION.pl
index 73a13572f0..22241c42bb 100644
--- a/Porting/cmpVERSION.pl
+++ b/Porting/cmpVERSION.pl
@@ -1,15 +1,15 @@
 #!/usr/bin/perl -w
 
 #
-# cmpVERSION - compare two Perl source trees for modules
-# that have identical version numbers but different contents.
+# cmpVERSION - compare the current Perl source tree and a given tag
+# for modules that have identical version numbers but different contents.
 #
 # with -d option, output the diffs too
 # with -x option, exclude dual-life modules (after all, there are tools
 #                 like core-cpan-diff that can already deal with them)
 #                 With this option, one of the directories must be '.'.
 #
-# Original by slaven@rezic.de, modified by jhi.
+# Original by slaven@rezic.de, modified by jhi and matt.w.johnson@gmail.com.
 #
 
 use strict;
@@ -25,7 +25,7 @@ use Maintainers;
 
 sub usage {
 die <<"EOF";
-usage: $0 [ -d -x ] source_dir1 source_dir2
+usage: $0 [ -d -x ] source_dir tag_to_compare
 EOF
 }
 
@@ -33,72 +33,103 @@ my %opts;
 getopts('dx', \%opts) or usage;
 @ARGV == 2 or usage;
 
-for (@ARGV[0, 1]) {
-    die "$0: '$_' does not look like Perl directory\n"
-	unless -f catfile($_, "perl.h") && -d catdir($_, "Porting");
-}
+my ($source_dir, $tag_to_compare) = @ARGV[0,1];
+die "$0: '$source_dir' does not look like a Perl directory\n"
+    unless -f catfile($source_dir, "perl.h") && -d catdir($source_dir, "Porting");
+die "$0: '$source_dir' is a Perl directory but does not look like Git working directory\n"
+    unless -d catdir($source_dir, ".git");
+
+my $tag_exists = `git --no-pager tag -l $tag_to_compare 2>/dev/null`;
+chomp $tag_exists;
+
+die "$0: '$tag_to_compare' is not a known Git tag\n"
+    unless $tag_exists eq $tag_to_compare;
 
 my %dual_files;
 if ($opts{x}) {
-    die "With -x, one of the directories must be '.'\n"
-	unless $ARGV[0] eq '.' or  $ARGV[1] eq '.';
+    die "With -x, the directory must be '.'\n"
+	unless $source_dir eq '.';
     for my $m (grep $Maintainers::Modules{$_}{CPAN},
 				keys %Maintainers::Modules)
     {
 
-	$dual_files{"./$_"} = 1 for Maintainers::get_module_files($m);
+	$dual_files{$_} = 1 for Maintainers::get_module_files($m);
     }
 }
 
-my $dir2 = rel2abs($ARGV[1]);
-chdir $ARGV[0] or die "$0: chdir '$ARGV[0]' failed: $!\n";
+chdir $source_dir or die "$0: chdir '$source_dir' failed: $!\n";
 
 # Files to skip from the check for one reason or another,
 # usually because they pull in their version from some other file.
 my %skip;
 @skip{
-    './lib/Carp/Heavy.pm',
-    './lib/Config.pm',		# no version number but contents will vary
-    './lib/Exporter/Heavy.pm',
-    './win32/FindExt.pm',
+    'lib/Carp/Heavy.pm',
+    'lib/Config.pm',		# no version number but contents will vary
+    'lib/Exporter/Heavy.pm',
+    'win32/FindExt.pm',
 } = ();
-my $skip_dirs = qr|^\./t/lib|;
-
-my @wanted;
-my @diffs;
-find(
-     sub { /\.pm$/ &&
-	       $File::Find::dir !~ $skip_dirs &&
-	       ! exists $skip{$File::Find::name} &&
-	       ! exists $dual_files{$File::Find::name}
-	       &&
-	       do { my $file2 =
-			catfile(catdir($dir2, $File::Find::dir), $_);
-		    (my $xs_file1 = $_)     =~ s/\.pm$/.xs/;
-		    (my $xs_file2 = $file2) =~ s/\.pm$/.xs/;
-		    my $eq1 = compare($_, $file2) == 0;
-		    my $eq2 = 1;
-		    if (-e $xs_file1 && -e $xs_file2) {
-		        $eq2 = compare($xs_file1, $xs_file2) == 0;
-		    }
-		    return if $eq1 && $eq2;
-		    my $version1 = eval {MM->parse_version($_)};
-		    my $version2 = eval {MM->parse_version($file2)};
-		    return unless
-			defined $version1 &&
-			defined $version2 &&
-                        $version1 eq $version2;
-		    push @wanted, $File::Find::name;
-		    push @diffs, [ "$File::Find::dir/$_", $file2 ] unless $eq1;
-		    push @diffs, [ "$File::Find::dir/$xs_file1", $xs_file2 ]
-								   unless $eq2;
-		} }, curdir);
-for (sort @wanted) {
+my $skip_dirs = qr|^t/lib|;
+
+my @all_diffs = `git --no-pager diff --name-only $tag_to_compare`;
+chomp @all_diffs;
+
+my @module_diffs = grep {
+    my $this_dir;
+    $this_dir = $1 if m/^(.*)\//;
+    /\.pm$/ &&
+    (!defined($this_dir) || ($this_dir !~ $skip_dirs)) &&
+    !exists $skip{$_} && 
+    !exists $dual_files{$_}
+} @all_diffs;
+
+my (@output_files, @output_diffs);
+
+foreach my $pm_file (@module_diffs) {
+    (my $xs_file = $pm_file) =~ s/\.pm$/.xs/;
+    my $pm_eq = compare_git_file($pm_file, $tag_to_compare);
+    next unless defined $pm_eq;
+    my $xs_eq = 1;
+    if (-e $xs_file) {
+        $xs_eq = compare_git_file($xs_file, $tag_to_compare);
+        next unless defined $xs_eq;
+    }
+    next if ($pm_eq && $xs_eq);
+    my $pm_version = eval {MM->parse_version($pm_file)};
+    my $orig_pm_content = get_file_from_git($pm_file, $tag_to_compare);
+    my $orig_pm_version = eval {MM->parse_version(\$orig_pm_content)};
+    next unless
+	defined $pm_version &&
+	defined $orig_pm_version &&
+        $pm_version eq $orig_pm_version;
+    push @output_files, $pm_file;
+    push @output_diffs, $pm_file unless $pm_eq;
+    push @output_diffs, $xs_file unless $xs_eq;
+}
+
+sub compare_git_file {
+    my ($file, $tag) = @_;
+    open(my $orig_fh, "-|", "git --no-pager show $tag:$file 2>/dev/null");
+    return undef if eof($orig_fh);
+    my $is_eq = compare($file, $orig_fh) == 0;
+    close($orig_fh);
+    return $is_eq;
+}
+
+sub get_file_from_git {
+    my ($file, $tag) = @_;
+    local $/ = undef;
+    my $file_content = `git --no-pager show $tag:$file 2>/dev/null`;
+    return $file_content;
+}
+
+for (sort @output_files) {
     print "$_\n";
 }
+
 exit unless $opts{d};
-for (sort { $a->[0] cmp $b->[0] } @diffs) {
+
+for (sort @output_diffs) {
     print "\n";
-    system "diff -du '$_->[0]' '$_->[1]'";
+    system "git --no-pager diff $tag_to_compare '$_'";
 }