fix(ValidatorSite): handle rare null pointer dereference in timeout

src/ripple/app/misc/impl/ValidatorSite.cpp

@@ -316,8 +316,19 @@ ValidatorSite::onRequestTimeout(std::size_t siteIdx, error_code const& ec)
 
  {
  std::lock_guard lock_site{sites_mutex_};
- JLOG(j_.warn()) << "Request for " << sites_[siteIdx].activeResource->uri
- << " took too long";
+ // In some circumstances, both this function and the response
+ // handler (onSiteFetch or onTextFetch) can get queued and
+ // processed. In all observed cases, the response handler
+ // processes a network error. Usually, this function runs first,
+ // but on extremely rare occasions, the response handler can run
+ // first, which will leave activeResource empty.
+ auto const& site = sites_[siteIdx];
+ if (site.activeResource)
+ JLOG(j_.warn()) << "Request for " << site.activeResource->uri
+ << " took too long";
+ else
+ JLOG(j_.error()) << "Request took too long, but a response has "
+ "already been processed";
  }
 
  std::lock_guard lock_state{state_mutex_};