gitweb: Show combined diff for merge commits in 'commit' view

When commit shown is a merge commit (has more than one parent),
display combined difftree output (result of git-diff-tree -c).
Earlier (since commit 549ab4a30703012ff3a12b5455d319216805a8db)
difftree output (against first parent) was not printed for merges.

Examples of non-trivial merges:
  5bac4a671907604b5fb4e24ff682d5b0e8431931 (includes rename)
  addafaf92eeb86033da91323d0d3ad7a496dae83 (five parents)
  95f97567c1887d77f3a46b42d8622c76414d964d (evil merge)

Signed-off-by: Jakub Narebski <redacted>
Signed-off-by: Junio C Hamano <redacted>

diff --git a/gitweb.perl b/gitweb.perl
index 68ef52eefb0b7b6d0d1f2af2c54eb624da27d6fc81b3941d3e955901e1f64a6a..144369cf8a78dacb3cba78006e204cbaf133e461032579e92d0f70b5e403afdf 100755 (executable)
--- a/gitweb.perl
+++ b/gitweb.perl
@@ -4027,14 +4027,13 @@ sub git_commit {
                $parent = "--root";
        }
        my @difftree;
-       if (@$parents <= 1) {
-               # difftree output is not printed for merges
-               open my $fd, "-|", git_cmd(), "diff-tree", '-r', "--no-commit-id",
-                       @diff_opts, $parent, $hash, "--"
-                       or die_error(undef, "Open git-diff-tree failed");
-               @difftree = map { chomp; $_ } <$fd>;
-               close $fd or die_error(undef, "Reading git-diff-tree failed");
-       }
+       open my $fd, "-|", git_cmd(), "diff-tree", '-r', "--no-commit-id",
+               @diff_opts,
+               (@$parents <= 1 ? $parent : '-c'),
+               $hash, "--"
+               or die_error(undef, "Open git-diff-tree failed");
+       @difftree = map { chomp; $_ } <$fd>;
+       close $fd or die_error(undef, "Reading git-diff-tree failed");
 
        # non-textual hash id's can be cached
        my $expires;
@@ -4112,10 +4111,7 @@ sub git_commit {
        git_print_log($co{'comment'});
        print "</div>\n";
 
-       if (@$parents <= 1) {
-               # do not output difftree/whatchanged for merges
-               git_difftree_body(\@difftree, $hash, $parent);
-       }
+       git_difftree_body(\@difftree, $hash, @$parents);
 
        git_footer_html();
 }