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

When 'commitdiff' action is requested without 'hp' (hash parent)
parameter, and commit given by 'h' (hash) parameter is merge commit,
show merge as combined diff.

Earlier for merge commits without 'hp' parameter diff to first parent
was shown.

Note that in compact combined (--cc) format 'uninteresting' hunks
omission mechanism can make that there is no patch corresponding to
line in raw format (difftree) output. That is why (at least for now)
we use --combined and not --cc format for showing commitdiff for merge
commits.

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

diff --git a/gitweb.perl b/gitweb.perl
index 49c21b99962ba1dba765237d6ec46f6ebcd062390af253f47ef717766dd8e7ec..68ef52eefb0b7b6d0d1f2af2c54eb624da27d6fc81b3941d3e955901e1f64a6a 100755 (executable)
--- a/gitweb.perl
+++ b/gitweb.perl
@@ -4392,8 +4392,10 @@ sub git_commitdiff {
                }
        }
 
+       my $hash_parent_param = $hash_parent;
        if (!defined $hash_parent) {
-               $hash_parent = $co{'parent'} || '--root';
+               $hash_parent_param =
+                       @{$co{'parents'}} > 1 ? '-c' : $co{'parent'} || '--root';
        }
 
        # read commitdiff
@@ -4402,7 +4404,7 @@ sub git_commitdiff {
        if ($format eq 'html') {
                open $fd, "-|", git_cmd(), "diff-tree", '-r', @diff_opts,
                        "--no-commit-id", "--patch-with-raw", "--full-index",
-                       $hash_parent, $hash, "--"
+                       $hash_parent_param, $hash, "--"
                        or die_error(undef, "Open git-diff-tree failed");
 
                while (my $line = <$fd>) {
@@ -4414,7 +4416,7 @@ sub git_commitdiff {
 
        } elsif ($format eq 'plain') {
                open $fd, "-|", git_cmd(), "diff-tree", '-r', @diff_opts,
-                       '-p', $hash_parent, $hash, "--"
+                       '-p', $hash_parent_param, $hash, "--"
                        or die_error(undef, "Open git-diff-tree failed");
 
        } else {
@@ -4470,10 +4472,10 @@ TEXT
 
        # write patch
        if ($format eq 'html') {
-               git_difftree_body(\@difftree, $hash, $hash_parent);
+               git_difftree_body(\@difftree, $hash, $hash_parent || @{$co{'parents'}});
                print "<br/>\n";
 
-               git_patchset_body($fd, \@difftree, $hash, $hash_parent);
+               git_patchset_body($fd, \@difftree, $hash, $hash_parent || @{$co{'parents'}});
                close $fd;
                print "</div>\n"; # class="page_body"
                git_footer_html();