git-pickaxe: simplify Octopus merges further

If more than one parents in an Octopus merge have the same
origin, ignore later ones because it would not make any
difference in the outcome.

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

builtin-pickaxe.c

@@ -915,6 +915,7 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
 		     i < MAXPARENT && parent;
 		     parent = parent->next, i++) {
 			struct commit *p = parent->item;
+			int j, same;
 
 			if (parent_origin[i])
 				continue;
@@ -934,7 +935,16 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
 				origin_decref(porigin);
 				goto finish;
 			}
-			parent_origin[i] = porigin;
+			for (j = same = 0; j < i; j++)
+				if (!hashcmp(parent_origin[j]->blob_sha1,
+					     porigin->blob_sha1)) {
+					same = 1;
+					break;
+				}
+			if (!same)
+				parent_origin[i] = porigin;
+			else
+				origin_decref(porigin);
 		}
 	}