Drop only accepted duplicate ext messages, don't cache errors (#902)

Co-authored-by: SpyCheese <[email protected]>

validator/impl/liteserver-cache.hpp

@@ -85,6 +85,10 @@ class LiteServerCacheImpl : public LiteServerCache {
     }
   }
 
+  void drop_send_message_from_cache(td::Bits256 key) override {
+    send_message_cache_.erase(key);
+  }
+
  private:
   struct CacheEntry : public td::ListNode {
     explicit CacheEntry(td::Bits256 key, td::BufferSlice value) : key_(key), value_(std::move(value)) {

validator/impl/liteserver.cpp

@@ -531,10 +531,13 @@ void LiteQuery::perform_sendMessage(td::BufferSlice data) {
   auto copy = data.clone();
   td::actor::send_closure_later(
       manager_, &ValidatorManager::check_external_message, std::move(copy),
-      [Self = actor_id(this), data = std::move(data), manager = manager_](td::Result<td::Ref<ExtMessage>> res) mutable {
-        if(res.is_error()) {
-           td::actor::send_closure(Self, &LiteQuery::abort_query,
-                                   res.move_as_error_prefix("cannot apply external message to current state : "s));
+      [Self = actor_id(this), data = std::move(data), manager = manager_, cache = cache_,
+       cache_key = cache_key_](td::Result<td::Ref<ExtMessage>> res) mutable {
+        if (res.is_error()) {
+          // Don't cache errors
+          td::actor::send_closure(cache, &LiteServerCache::drop_send_message_from_cache, cache_key);
+          td::actor::send_closure(Self, &LiteQuery::abort_query,
+                                  res.move_as_error_prefix("cannot apply external message to current state : "s));
         } else {
           LOG(INFO) << "sending an external message to validator manager";
           td::actor::send_closure_later(manager, &ValidatorManager::send_external_message, res.move_as_ok());

validator/interfaces/liteserver.h

@@ -32,6 +32,7 @@ class LiteServerCache : public td::actor::Actor {
   virtual void update(td::Bits256 key, td::BufferSlice value) = 0;
 
   virtual void process_send_message(td::Bits256 key, td::Promise<td::Unit> promise) = 0;
+  virtual void drop_send_message_from_cache(td::Bits256 key) = 0;
 };
 
 } // namespace ton::validator