revision: clarify a 'return NULL' in get_reference()

When we know a pointer variable is NULL, it's clearer to
explicitly return NULL than to return that variable.

In get_reference(), when 'object' is NULL, we already return NULL
when 'revs->exclude_promisor_objects && is_promisor_object(oid)' is
true, but we return 'object' when 'revs->ignore_missing' is true.

Let's make the code clearer and more uniform by also explicitly
returning NULL when 'revs->ignore_missing' is true.

Helped-by: Eric Sunshine <[email protected]>
Signed-off-by: Christian Couder <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: chriscool

revision.c

@@ -385,7 +385,7 @@ static struct object *get_reference(struct rev_info *revs, const char *name,
 
 	if (!object) {
 		if (revs->ignore_missing)
-			return object;
+			return NULL;
 		if (revs->exclude_promisor_objects && is_promisor_object(oid))
 			return NULL;
 		die("bad object %s", name);