Fix "git show --stat"

Signed-off-by: Junio C Hamano <junkio@cox.net>

revision.c

@@ -789,7 +789,8 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 	}
 	if (revs->combine_merges) {
 		revs->ignore_merges = 0;
-		if (revs->dense_combined_merges)
+		if (revs->dense_combined_merges &&
+		    (revs->diffopt.output_format != DIFF_FORMAT_DIFFSTAT))
 			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 	}
 	revs->diffopt.abbrev = revs->abbrev;