Piecing it together from existing tools isn't really hard, and made for a nice distraction.
Call it as './git-blame-diff.perl HEAD^ HEAD' or so.
This lacks proper argument checking and a chdir to the repository top level. Maybe you could fill in the gaps and shape it as a contrib patch? For bonus points, change it so that the workdir version can be used as the new side of the diff, by omitting the second argument.
--- 8< --- #!/usr/bin/perl -w
sub parse_hunk_header {
my ($line) = @_;
my ($o_ofs, $o_cnt, $n_ofs, $n_cnt) =
$line =~ /^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/;
$o_cnt = 1 unless defined $o_cnt;
$n_cnt = 1 unless defined $n_cnt;
return ($o_ofs, $o_cnt, $n_ofs, $n_cnt);
}sub get_blame_prefix {
my ($line) = @_;
$line =~ /^([0-9a-f]+\s+\([^\)]+\))/ or die "bad blame output: $line";
return $1;
}my ($oldrev, $newrev) = @ARGV; open($diff, '-|', 'git', '--no-pager', 'diff', $oldrev, $newrev) or die;
my ($pre, $post);
my $filename;
while (<$diff>) {
if (m{^diff --git ./(.*) ./\1$}) {
$filename = $1;
} elsif (m{^(\+\+\+|---) ./$filename$}) {
# ignore
} elsif (m{^@@ }) {
my ($o_ofs, $o_cnt, $n_ofs, $n_cnt)
= parse_hunk_header($_);
my $o_end = $o_ofs + $o_cnt;
my $n_end = $n_ofs + $n_cnt;
open($pre, '-|', 'git', 'blame', "-L$o_ofs,$o_end",
$oldrev, '--', $filename) or die;
open($post, '-|', 'git', 'blame', "-L$n_ofs,$n_end",
$newrev, '--', $filename) or die;
} elsif (m{^ }) {
print get_blame_prefix(scalar <$pre>), "\t", $_;
scalar <$post>; # discard
} elsif (m{^\-}) {
print get_blame_prefix(scalar <$pre>), "\t", $_;
} elsif (m{^\+}) {
print get_blame_prefix(scalar <$post>), "\t", $_;
}
}
