gitweb: Support comparing blobs (files) with different names

Fix the bug that caused "blobdiff" view called with new style URI
for a rename with change diff to be show as new (added) file diff.

New style URI for "blobdiff" for rename means with $hash_base ('hb') and
$hash_parent_base ('hpb') paramaters denoting tree-ish (usually commit)
of a blobs being compared, together with both $file_name ('f') and
$file_parent ('fp') parameters.

It is done by adding $file_parent ('fp') to the path limiter, meaning
that diff command becomes:

	git diff-tree [options] hpb hb -- fp f

Other option would be finding hash of a blob using git_get_hash_by_path
subroutine and comparing blobs using git-diff, or using extended SHA-1
syntax and compare blobs using git-diff:

	git diff [options] hpb:fp hp:f

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 3348583..3786955 100755 (executable)
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -3885,7 +3885,7 @@ sub git_blobdiff {
                        # read raw output
                        open $fd, "-|", git_cmd(), "diff-tree", '-r', @diff_opts,
                                $hash_parent_base, $hash_base,
-                               "--", $file_name
+                               "--", (defined $file_parent ? $file_parent : ()), $file_name
                                or die_error(undef, "Open git-diff-tree failed");
                        @difftree = map { chomp; $_ } <$fd>;
                        close $fd
@@ -3935,7 +3935,7 @@ sub git_blobdiff {
                # open patch output
                open $fd, "-|", git_cmd(), "diff-tree", '-r', @diff_opts,
                        '-p', $hash_parent_base, $hash_base,
-                       "--", $file_name
+                       "--", (defined $file_parent ? $file_parent : ()), $file_name
                        or die_error(undef, "Open git-diff-tree failed");
        }