diff --git a/refs.c b/refs.c
index ea0f598efe..7417f9a5af 100644
--- a/refs.c
+++ b/refs.c
@@ -84,6 +84,25 @@ static int ref_entry_cmp(const void *a, const void *b)
 	return strcmp(one->name, two->name);
 }
 
+/*
+ * Emit a warning and return true iff ref1 and ref2 have the same name
+ * and the same sha1.  Die if they have the same name but different
+ * sha1s.
+ */
+static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
+{
+	if (!strcmp(ref1->name, ref2->name)) {
+		/* Duplicate name; make sure that the SHA1s match: */
+		if (hashcmp(ref1->sha1, ref2->sha1))
+			die("Duplicated ref, and SHA1s don't match: %s",
+			    ref1->name);
+		warning("Duplicated ref: %s", ref1->name);
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
 static void sort_ref_array(struct ref_array *array)
 {
 	int i = 0, j = 1;
@@ -98,11 +117,7 @@ static void sort_ref_array(struct ref_array *array)
 	for (; j < array->nr; j++) {
 		struct ref_entry *a = array->refs[i];
 		struct ref_entry *b = array->refs[j];
-		if (!strcmp(a->name, b->name)) {
-			if (hashcmp(a->sha1, b->sha1))
-				die("Duplicated ref, and SHA1s don't match: %s",
-				    a->name);
-			warning("Duplicated ref: %s", a->name);
+		if (is_dup_ref(a, b)) {
 			free(b);
 			continue;
 		}