fetch: use ref_namespaces during prefetch

The "refs/prefetch/" namespace is used by 'git fetch --prefetch' as a
replacement of the destination of the refpsec for a remote. Git also
removes refspecs that include tags.

Instead of using string literals for the 'refs/tags/ and
'refs/prefetch/' namespaces, use the entries in the ref_namespaces
array.

This kind of change could be done in many places around the codebase,
but we are isolating only to this change because of the way the
refs/prefetch/ namespace somewhat motivated the creation of the
ref_namespaces array.

Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

builtin/fetch.c

@@ -490,7 +490,9 @@ static void filter_prefetch_refspec(struct refspec *rs)
 			continue;
 		if (!rs->items[i].dst ||
 		    (rs->items[i].src &&
-		     !strncmp(rs->items[i].src, "refs/tags/", 10))) {
+		     !strncmp(rs->items[i].src,
+			      ref_namespace[NAMESPACE_TAGS].ref,
+			      strlen(ref_namespace[NAMESPACE_TAGS].ref)))) {
 			int j;
 
 			free(rs->items[i].src);
@@ -506,7 +508,7 @@ static void filter_prefetch_refspec(struct refspec *rs)
 		}
 
 		old_dst = rs->items[i].dst;
-		strbuf_addstr(&new_dst, "refs/prefetch/");
+		strbuf_addstr(&new_dst, ref_namespace[NAMESPACE_PREFETCH].ref);
 
 		/*
 		 * If old_dst starts with "refs/", then place