refs: use size_t indexes when iterating over ref transaction updates

Eliminate any chance of integer overflow on platforms where the two
types have different sizes.

Signed-off-by: Michael Haggerty <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: mhagger

refs.c

@@ -848,7 +848,7 @@ struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 
 void ref_transaction_free(struct ref_transaction *transaction)
 {
-	int i;
+	size_t i;
 
 	if (!transaction)
 		return;

refs/files-backend.c

@@ -2850,7 +2850,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE,
 			       "ref_transaction_commit");
-	int ret = 0, i;
+	size_t i;
+	int ret = 0;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
@@ -3057,7 +3058,8 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE,
 			       "initial_ref_transaction_commit");
-	int ret = 0, i;
+	size_t i;
+	int ret = 0;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
 	assert(err);