combine-diff: move show_log_first logic/action out of paths scanning

Judging from sample outputs and tests nothing changes in diff -c output,
and this change will help later patches, when we'll be refactoring paths
scanning into its own function with several variants - the
show_log_first logic / code will stay common to all of them.

NOTE: only now we have to take care to explicitly not show anything if
parents array is empty, as in fact there are some clients in Git code,
which calls diff_tree_combined() in such a way.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/combine-diff.c b/combine-diff.c
index 24ca7e2334b68e06afd24051ad1aafcc129bcba4..68d2e53be66c5085ab908cfc14c01f00ac1be6f0 100644 (file)
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -1311,6 +1311,20 @@ void diff_tree_combined(const unsigned char *sha1,
        struct combine_diff_path *p, *paths = NULL;
        int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
 
+       /* nothing to do, if no parents */
+       if (!num_parent)
+               return;
+
+       show_log_first = !!rev->loginfo && !rev->no_commit_id;
+       needsep = 0;
+       if (show_log_first) {
+               show_log(rev);
+
+               if (rev->verbose_header && opt->output_format)
+                       printf("%s%c", diff_line_prefix(opt),
+                              opt->line_termination);
+       }
+
        diffopts = *opt;
        copy_pathspec(&diffopts.pathspec, &opt->pathspec);
        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
@@ -1319,8 +1333,6 @@ void diff_tree_combined(const unsigned char *sha1,
        /* tell diff_tree to emit paths in sorted (=tree) order */
        diffopts.orderfile = NULL;
 
-       show_log_first = !!rev->loginfo && !rev->no_commit_id;
-       needsep = 0;
        /* find set of paths that everybody touches */
        for (i = 0; i < num_parent; i++) {
                /* show stat against the first parent even
@@ -1336,14 +1348,6 @@ void diff_tree_combined(const unsigned char *sha1,
                diffcore_std(&diffopts);
                paths = intersect_paths(paths, i, num_parent);
 
-               if (show_log_first && i == 0) {
-                       show_log(rev);
-
-                       if (rev->verbose_header && opt->output_format)
-                               printf("%s%c", diff_line_prefix(opt),
-                                      opt->line_termination);
-               }
-
                /* if showing diff, show it in requested order */
                if (diffopts.output_format != DIFF_FORMAT_NO_OUTPUT &&
                    opt->orderfile) {