[tor-bugs] #8231 [Tor]: Clients can go crazy when unable to find directory guards

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#8231: Clients can go crazy when unable to find directory guards
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 Reporter:  nickm       |          Owner:                    
     Type:  defect      |         Status:  needs_review      
 Priority:  critical    |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor         |        Version:                    
 Keywords:  tor-client  |         Parent:                    
   Points:              |   Actualpoints:                    
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Comment(by andrea):

 Replying to [comment:2 arma]:
 > {{{
 > +  if (entry_guard_get_by_id_digest(node->identity) != NULL) {
 > +    log_info(LD_CIRC, "I was about to add a duplicate entry guard.");
 > +    /* This can happen if we choose a guard, then the node goes away,
 then
 > +     * comes back. */
 > +    ((node_t*) node)->using_as_guard = 1;
 > +    return NULL;
 > +  }
 > }}}
 >
 > don't we want to return the guard here, to show success?

 I think we want to return NULL, since it looks like the things that call
 this mainly use the return value to know if the guard list changed.  The
 comment for the add_an_entry_guard() function could perhaps do a better
 job of explaining this.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8231#comment:3>
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