Bridge-using clients now use their cached microdesc consensus

Clients that use bridges were ignoring their cached microdesc-flavor
consensus files, because they only thought they should use the microdesc
flavor once they had a known-working bridge that could offer microdescs,
and at first boot no bridges are known-working.

This bug caused bridge-using clients to download a new microdesc consensus
on each startup.

Fixes bug 20269; bugfix on 0.2.3.12-alpha.

changes/bug20269

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - When clients that use bridges start up with a cached consensus
+      on disk, they were ignoring it and downloading a new one. Now they
+      use the cached one. Fixes bug 20269; bugfix on 0.2.3.12-alpha.

src/or/entrynodes.c

@@ -2521,27 +2521,6 @@ entries_retry_all(const or_options_t *options)
   entries_retry_helper(options, 1);
 }
 
-/** Return true if at least one of our bridges runs a Tor version that can
- * provide microdescriptors to us. If not, we'll fall back to asking for
- * full descriptors. */
-int
-any_bridge_supports_microdescriptors(void)
-{
-  const node_t *node;
-  if (!get_options()->UseBridges || !entry_guards)
-    return 0;
-  SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
-    node = node_get_by_id(e->identity);
-    if (node && node->is_running &&
-        node_is_bridge(node) && node_is_a_configured_bridge(node)) {
-      /* This is one of our current bridges, and we know enough about
-       * it to know that it will be able to answer our questions. */
-       return 1;
-    }
-  } SMARTLIST_FOREACH_END(e);
-  return 0;
-}
-
 /** Release all storage held by the list of entry guards and related
  * memory structs. */
 void

src/or/entrynodes.h

@@ -143,7 +143,6 @@ int any_bridge_descriptors_known(void);
 int entries_known_but_down(const or_options_t *options);
 void entries_retry_all(const or_options_t *options);
 
-int any_bridge_supports_microdescriptors(void);
 const smartlist_t *get_socks_args_by_bridge_addrport(const tor_addr_t *addr,
                                                      uint16_t port);
 

src/or/microdesc.c

@@ -920,11 +920,7 @@ we_use_microdescriptors_for_circuits(const or_options_t *options)
   int ret = options->UseMicrodescriptors;
   if (ret == -1) {
     /* UseMicrodescriptors is "auto"; we need to decide: */
-    /* If we are configured to use bridges and none of our bridges
-     * know what a microdescriptor is, the answer is no. */
-    if (options->UseBridges && !any_bridge_supports_microdescriptors())
-      return 0;
-    /* Otherwise, we decide that we'll use microdescriptors iff we are
+    /* We'll use microdescriptors iff we are
      * not a server, and we're not autofetching everything. */
     /* XXXX++ what does not being a server have to do with it? also there's
      * a partitioning issue here where bridges differ from clients. */