Merge branch 'jc/maint-fetch-alt'

* jc/maint-fetch-alt:
  fetch-pack: objects in our alternates are available to us
  refs_from_alternate: helper to use refs from alternates

Conflicts:
	builtin/receive-pack.c

diff --cc builtin/fetch-pack.c
Simple merge

diff --cc builtin/receive-pack.c
Simple merge

diff --cc transport.c
index f1c07816e01bb0b1ad93d7665b1374e8cd36e6cb,3dfbc6a79c402bac5e18de97a12c131b556597c4..a02f79aae3d91ea4109d21a9ed9ca2d962125375
--- 1/transport.c
--- 2/transport.c
+++ b/transport.c
@@@ -1189,3 -1189,37 +1189,37 @@@ char *transport_anonymize_url(const cha
  literal_copy:
        return xstrdup(url);
  }
 -      other = xstrdup(make_absolute_path(e->base));
+ 
+ int refs_from_alternate_cb(struct alternate_object_database *e, void *cb)
+ {
+       char *other;
+       size_t len;
+       struct remote *remote;
+       struct transport *transport;
+       const struct ref *extra;
+       alternate_ref_fn *ref_fn = cb;
+ 
+       e->name[-1] = '\0';
++      other = xstrdup(real_path(e->base));
+       e->name[-1] = '/';
+       len = strlen(other);
+ 
+       while (other[len-1] == '/')
+               other[--len] = '\0';
+       if (len < 8 || memcmp(other + len - 8, "/objects", 8))
+               return 0;
+       /* Is this a git repository with refs? */
+       memcpy(other + len - 8, "/refs", 6);
+       if (!is_directory(other))
+               return 0;
+       other[len - 8] = '\0';
+       remote = remote_get(other);
+       transport = transport_get(remote, other);
+       for (extra = transport_get_remote_refs(transport);
+            extra;
+            extra = extra->next)
+               ref_fn(extra, NULL);
+       transport_disconnect(transport);
+       free(other);
+       return 0;
+ }