Fix estimating block size, repeat collation on error (#1178)

* Fix extimating block size, repeat collation on error

* Cancel collation when it is non needed

crypto/block/block.h

@@ -239,6 +239,12 @@ struct ParamLimits {
   bool deserialize(vm::CellSlice& cs);
   int classify(td::uint64 value) const;
   bool fits(unsigned cls, td::uint64 value) const;
+  void multiply_by(double x) {
+    CHECK(x > 0.0);
+    for (td::uint32& y : limits_) {
+      y = (td::uint32)std::min<double>(y * x, 1e9);
+    }
+  }
 
  private:
   std::array<td::uint32, limits_cnt> limits_;

validator/fabric.h

@@ -26,6 +26,8 @@ namespace ton {
 
 namespace validator {
 
+enum CollateMode { skip_store_candidate = 1 };
+
 td::actor::ActorOwn<Db> create_db_actor(td::actor::ActorId<ValidatorManager> manager, std::string db_root_,
                                         td::Ref<ValidatorManagerOptions> opts);
 td::actor::ActorOwn<LiteServerCache> create_liteserver_cache_actor(td::actor::ActorId<ValidatorManager> manager,
@@ -81,7 +83,8 @@ void run_validate_query(ShardIdFull shard, BlockIdExt min_masterchain_block_id,
 void run_collate_query(ShardIdFull shard, const BlockIdExt& min_masterchain_block_id, std::vector<BlockIdExt> prev,
                        Ed25519_PublicKey creator, td::Ref<ValidatorSet> validator_set,
                        td::Ref<CollatorOptions> collator_opts, td::actor::ActorId<ValidatorManager> manager,
-                       td::Timestamp timeout, td::Promise<BlockCandidate> promise);
+                       td::Timestamp timeout, td::Promise<BlockCandidate> promise,
+                       td::CancellationToken cancellation_token, unsigned mode, int attempt_idx = 0);
 void run_collate_hardfork(ShardIdFull shard, const BlockIdExt& min_masterchain_block_id, std::vector<BlockIdExt> prev,
                           td::actor::ActorId<ValidatorManager> manager, td::Timestamp timeout,
                           td::Promise<BlockCandidate> promise);

validator/impl/collator-impl.h

@@ -76,6 +76,9 @@ class Collator final : public td::actor::Actor {
   td::Timestamp timeout;
   td::Timestamp queue_cleanup_timeout_, soft_timeout_, medium_timeout_;
   td::Promise<BlockCandidate> main_promise;
+  unsigned mode_ = 0;
+  int attempt_idx_;
+  bool allow_repeat_collation_ = false;
   ton::BlockSeqno last_block_seqno{0};
   ton::BlockSeqno prev_mc_block_seqno{0};
   ton::BlockSeqno new_block_seqno{0};
@@ -90,7 +93,8 @@ class Collator final : public td::actor::Actor {
  public:
   Collator(ShardIdFull shard, bool is_hardfork, BlockIdExt min_masterchain_block_id, std::vector<BlockIdExt> prev,
            Ref<ValidatorSet> validator_set, Ed25519_PublicKey collator_id, Ref<CollatorOptions> collator_opts,
-           td::actor::ActorId<ValidatorManager> manager, td::Timestamp timeout, td::Promise<BlockCandidate> promise);
+           td::actor::ActorId<ValidatorManager> manager, td::Timestamp timeout, td::Promise<BlockCandidate> promise,
+           td::CancellationToken cancellation_token, unsigned mode, int attempt_idx);
   ~Collator() override = default;
   bool is_busy() const {
     return busy_;
@@ -318,6 +322,7 @@ class Collator final : public td::actor::Actor {
   bool insert_out_msg(Ref<vm::Cell> out_msg);
   bool insert_out_msg(Ref<vm::Cell> out_msg, td::ConstBitPtr msg_hash);
   bool register_out_msg_queue_op(bool force = false);
+  bool register_dispatch_queue_op(bool force = false);
   bool update_min_mc_seqno(ton::BlockSeqno some_mc_seqno);
   bool combine_account_transactions();
   bool update_public_libraries();
@@ -348,10 +353,14 @@ class Collator final : public td::actor::Actor {
   bool create_block();
   Ref<vm::Cell> collate_shard_block_descr_set();
   bool create_collated_data();
+
   bool create_block_candidate();
   void return_block_candidate(td::Result<td::Unit> saved);
   bool update_last_proc_int_msg(const std::pair<ton::LogicalTime, ton::Bits256>& new_lt_hash);
 
+  td::CancellationToken cancellation_token_;
+  bool check_cancelled();
+
  public:
   static td::uint32 get_skip_externals_queue_size();
 

validator/impl/collator.cpp

@@ -45,11 +45,13 @@ using td::Ref;
 using namespace std::literals::string_literals;
 
 // Don't increase MERGE_MAX_QUEUE_LIMIT too much: merging requires cleaning the whole queue in out_msg_queue_cleanup
-static const td::uint32 FORCE_SPLIT_QUEUE_SIZE = 4096;
+static constexpr td::uint32 FORCE_SPLIT_QUEUE_SIZE = 4096;
-static const td::uint32 SPLIT_MAX_QUEUE_SIZE = 100000;
+static constexpr td::uint32 SPLIT_MAX_QUEUE_SIZE = 100000;
-static const td::uint32 MERGE_MAX_QUEUE_SIZE = 2047;
+static constexpr td::uint32 MERGE_MAX_QUEUE_SIZE = 2047;
-static const td::uint32 SKIP_EXTERNALS_QUEUE_SIZE = 8000;
+static constexpr td::uint32 SKIP_EXTERNALS_QUEUE_SIZE = 8000;
-static const int HIGH_PRIORITY_EXTERNAL = 10;  // don't skip high priority externals when queue is big
+static constexpr int HIGH_PRIORITY_EXTERNAL = 10;  // don't skip high priority externals when queue is big
+
+static constexpr int MAX_ATTEMPTS = 5;
 
 #define DBG(__n) dbg(__n)&&
 #define DSTART int __dcnt = 0;
@@ -74,11 +76,15 @@ static inline bool dbg(int c) {
  * @param manager The ActorId of the ValidatorManager.
  * @param timeout The timeout for the collator.
  * @param promise The promise to return the result.
+ * @param cancellation_token Token to cancel collation.
+ * @param mode +1 - skip storing candidate to disk.
+ * @param attempt_idx The index of the attempt, starting from 0. On later attempts collator decreases block limits and skips some steps.
  */
 Collator::Collator(ShardIdFull shard, bool is_hardfork, BlockIdExt min_masterchain_block_id,
                    std::vector<BlockIdExt> prev, td::Ref<ValidatorSet> validator_set, Ed25519_PublicKey collator_id,
                    Ref<CollatorOptions> collator_opts, td::actor::ActorId<ValidatorManager> manager,
-                   td::Timestamp timeout, td::Promise<BlockCandidate> promise)
+                   td::Timestamp timeout, td::Promise<BlockCandidate> promise, td::CancellationToken cancellation_token,
+                   unsigned mode, int attempt_idx)
     : shard_(shard)
     , is_hardfork_(is_hardfork)
     , min_mc_block_id{min_masterchain_block_id}
@@ -93,9 +99,13 @@ Collator::Collator(ShardIdFull shard, bool is_hardfork, BlockIdExt min_mastercha
     , soft_timeout_(td::Timestamp::at(timeout.at() - 3.0))
     , medium_timeout_(td::Timestamp::at(timeout.at() - 1.5))
     , main_promise(std::move(promise))
-    , perf_timer_("collate", 0.1, [manager](double duration) {
+    , mode_(mode)
-      send_closure(manager, &ValidatorManager::add_perf_timer_stat, "collate", duration);
+    , attempt_idx_(attempt_idx)
-    }) {
+    , perf_timer_("collate", 0.1,
+                  [manager](double duration) {
+                    send_closure(manager, &ValidatorManager::add_perf_timer_stat, "collate", duration);
+                  })
+    , cancellation_token_(std::move(cancellation_token)) {
 }
 
 /**
@@ -107,7 +117,11 @@ Collator::Collator(ShardIdFull shard, bool is_hardfork, BlockIdExt min_mastercha
  * The results of these queries are handled by corresponding callback functions.
  */
 void Collator::start_up() {
-  LOG(WARNING) << "Collator for shard " << shard_.to_str() << " started";
+  LOG(WARNING) << "Collator for shard " << shard_.to_str() << " started"
+               << (attempt_idx_ ? PSTRING() << " (attempt #" << attempt_idx_ << ")" : "");
+  if (!check_cancelled()) {
+    return;
+  }
   LOG(DEBUG) << "Previous block #1 is " << prev_blocks.at(0).to_str();
   if (prev_blocks.size() > 1) {
     LOG(DEBUG) << "Previous block #2 is " << prev_blocks.at(1).to_str();
@@ -340,7 +354,15 @@ bool Collator::fatal_error(td::Status error) {
   error.ensure_error();
   LOG(ERROR) << "cannot generate block candidate for " << show_shard(shard_) << " : " << error.to_string();
   if (busy_) {
-    main_promise(std::move(error));
+    if (allow_repeat_collation_ && error.code() != ErrorCode::cancelled && attempt_idx_ + 1 < MAX_ATTEMPTS &&
+        !is_hardfork_ && !timeout.is_in_past()) {
+      LOG(WARNING) << "Repeating collation (attempt #" << attempt_idx_ + 1 << ")";
+      run_collate_query(shard_, min_mc_block_id, prev_blocks, created_by_, validator_set_, collator_opts_, manager,
+                        td::Timestamp::in(10.0), std::move(main_promise), std::move(cancellation_token_), mode_,
+                        attempt_idx_ + 1);
+    } else {
+      main_promise(std::move(error));
+    }
     busy_ = false;
   }
   stop();
@@ -382,6 +404,9 @@ bool Collator::fatal_error(std::string err_msg, int err_code) {
  */
 void Collator::check_pending() {
   // LOG(DEBUG) << "pending = " << pending;
+  if (!check_cancelled()) {
+    return;
+  }
   if (!pending) {
     step = 2;
     try {
@@ -712,6 +737,15 @@ bool Collator::unpack_last_mc_state() {
     return fatal_error(limits.move_as_error());
   }
   block_limits_ = limits.move_as_ok();
+  if (attempt_idx_ == 3) {
+    LOG(INFO) << "Attempt #3: bytes, gas limits /= 2";
+    block_limits_->bytes.multiply_by(0.5);
+    block_limits_->gas.multiply_by(0.5);
+  } else if (attempt_idx_ == 4) {
+    LOG(INFO) << "Attempt #4: bytes, gas limits /= 4";
+    block_limits_->bytes.multiply_by(0.25);
+    block_limits_->gas.multiply_by(0.25);
+  }
   LOG(DEBUG) << "block limits: bytes [" << block_limits_->bytes.underload() << ", " << block_limits_->bytes.soft()
              << ", " << block_limits_->bytes.hard() << "]";
   LOG(DEBUG) << "block limits: gas [" << block_limits_->gas.underload() << ", " << block_limits_->gas.soft() << ", "
@@ -2093,6 +2127,7 @@ bool Collator::do_collate() {
   if (max_lt == start_lt) {
     ++max_lt;
   }
+  allow_repeat_collation_ = true;
   // NB: interchanged 1.2 and 1.1 (is this always correct?)
   // 1.1. re-adjust neighbors' out_msg_queues (for oneself)
   if (!add_trivial_neighbor()) {
@@ -2333,6 +2368,9 @@ bool Collator::out_msg_queue_cleanup() {
         LOG(WARNING) << "cleaning up outbound queue takes too long, ending";
         break;
       }
+      if (!check_cancelled()) {
+        return false;
+      }
       if (i == queue_parts.size()) {
         i = 0;
       }
@@ -3532,6 +3570,9 @@ bool Collator::process_inbound_internal_messages() {
       stats_.limits_log += PSTRING() << "INBOUND_INT_MESSAGES: timeout\n";
       break;
     }
+    if (!check_cancelled()) {
+      return false;
+    }
     auto kv = nb_out_msgs_->extract_cur();
     CHECK(kv && kv->msg.not_null());
     LOG(DEBUG) << "processing inbound message with (lt,hash)=(" << kv->lt << "," << kv->key.to_hex()
@@ -3565,6 +3606,10 @@ bool Collator::process_inbound_external_messages() {
     LOG(INFO) << "skipping processing of inbound external messages";
     return true;
   }
+  if (attempt_idx_ >= 2) {
+    LOG(INFO) << "Attempt #" << attempt_idx_ << ": skip external messages";
+    return true;
+  }
   if (out_msg_queue_size_ > SKIP_EXTERNALS_QUEUE_SIZE) {
     LOG(INFO) << "skipping processing of inbound external messages (except for high-priority) because out_msg_queue is "
                  "too big ("
@@ -3586,6 +3631,9 @@ bool Collator::process_inbound_external_messages() {
       stats_.limits_log += PSTRING() << "INBOUND_EXT_MESSAGES: timeout\n";
       break;
     }
+    if (!check_cancelled()) {
+      return false;
+    }
     auto ext_msg = ext_msg_struct.cell;
     ton::Bits256 hash{ext_msg->get_hash().bits()};
     int r = process_external_message(std::move(ext_msg));
@@ -3692,6 +3740,10 @@ bool Collator::process_dispatch_queue() {
     if (max_per_initiator[iter] == 0 || max_total_count[iter] == 0) {
       continue;
     }
+    if (iter > 0 && attempt_idx_ >= 1) {
+      LOG(INFO) << "Attempt #" << attempt_idx_ << ": skip process_dispatch_queue";
+      break;
+    }
     vm::AugmentedDictionary cur_dispatch_queue{dispatch_queue_->get_root(), 256, block::tlb::aug_DispatchQueue};
     std::map<std::tuple<WorkchainId, StdSmcAddress, LogicalTime>, size_t> count_per_initiator;
     size_t total_count = 0;
@@ -3704,13 +3756,13 @@ bool Collator::process_dispatch_queue() {
         stats_.limits_log += PSTRING() << "DISPATCH_QUEUE_STAGE_" << iter << ": "
                                        << block_full_comment(*block_limit_status_, block::ParamLimits::cl_normal)
                                        << "\n";
-        return true;
+        return register_dispatch_queue_op(true);
       }
       if (soft_timeout_.is_in_past(td::Timestamp::now())) {
         block_full_ = true;
         LOG(WARNING) << "soft timeout reached, stop processing dispatch queue";
         stats_.limits_log += PSTRING() << "DISPATCH_QUEUE_STAGE_" << iter << ": timeout\n";
-        return true;
+        return register_dispatch_queue_op(true);
       }
       StdSmcAddress src_addr;
       td::Ref<vm::CellSlice> account_dispatch_queue;
@@ -3788,6 +3840,7 @@ bool Collator::process_dispatch_queue() {
     if (iter == 0) {
       have_unprocessed_account_dispatch_queue_ = false;
     }
+    register_dispatch_queue_op(true);
   }
   return true;
 }
@@ -3811,12 +3864,7 @@ bool Collator::process_deferred_message(Ref<vm::CellSlice> enq_msg, StdSmcAddres
     return fatal_error(PSTRING() << "failed to delete message from DispatchQueue: address=" << src_addr.to_hex()
                                  << ", lt=" << lt);
   }
-  ++dispatch_queue_ops_;
+  register_dispatch_queue_op();
-  if (!(dispatch_queue_ops_ & 63)) {
-    if (!block_limit_status_->add_proof(dispatch_queue_->get_root_cell())) {
-      return false;
-    }
-  }
   ++sender_generated_messages_count_[src_addr];
 
   LogicalTime enqueued_lt = 0;
@@ -3909,6 +3957,7 @@ bool Collator::process_deferred_message(Ref<vm::CellSlice> enq_msg, StdSmcAddres
   ++unprocessed_deferred_messages_[src_addr];
   LOG(INFO) << "delivering deferred message from account " << src_addr.to_hex() << ", lt=" << lt
             << ", emitted_lt=" << emitted_lt;
+  block_limit_status_->add_cell(msg_env);
   register_new_msg(std::move(new_msg));
   msg_metadata = std::move(env.metadata);
   return true;
@@ -4088,11 +4137,7 @@ bool Collator::enqueue_message(block::NewOutMsg msg, td::RefInt256 fwd_fees_rema
     }
     ++dispatch_dict_size;
     dispatch_queue_->set(src_addr, block::pack_account_dispatch_queue(dispatch_dict, dispatch_dict_size));
-    ++dispatch_queue_ops_;
+    return register_dispatch_queue_op();
-    if (!(dispatch_queue_ops_ & 63)) {
-      return block_limit_status_->add_proof(dispatch_queue_->get_root_cell());
-    }
-    return true;
   }
 
   auto next_hop = block::interpolate_addr(src_prefix, dest_prefix, route_info.second);
@@ -4134,6 +4179,9 @@ bool Collator::process_new_messages(bool enqueue_only) {
       stats_.limits_log += PSTRING() << "NEW_MESSAGES: "
                                      << block_full_comment(*block_limit_status_, block::ParamLimits::cl_normal) << "\n";
     }
+    if (!check_cancelled()) {
+      return false;
+    }
     LOG(DEBUG) << "have message with lt=" << msg.lt;
     int res = process_one_new_message(std::move(msg), enqueue_only);
     if (res < 0) {
@@ -4973,6 +5021,23 @@ bool Collator::register_out_msg_queue_op(bool force) {
   }
 }
 
+/**
+ * Registers a dispatch queue message queue operation.
+ * Adds the proof to the block limit status every 64 operations.
+ *
+ * @param force If true, the proof will always be added to the block limit status.
+ *
+ * @returns True if the operation was successfully registered, false otherwise.
+ */
+bool Collator::register_dispatch_queue_op(bool force) {
+  ++dispatch_queue_ops_;
+  if (force || !(dispatch_queue_ops_ & 63)) {
+    return block_limit_status_->add_proof(dispatch_queue_->get_root_cell());
+  } else {
+    return true;
+  }
+}
+
 /**
  * Creates a new shard state and the Merkle update.
  *
@@ -5098,9 +5163,10 @@ bool Collator::compute_out_msg_queue_info(Ref<vm::Cell>& out_msg_queue_info) {
   vm::CellSlice maybe_extra = cb.as_cellslice();
   cb.reset();
 
-  return register_out_msg_queue_op(true) && out_msg_queue_->append_dict_to_bool(cb)  // _ out_queue:OutMsgQueue
+  return register_out_msg_queue_op(true) && register_dispatch_queue_op(true) &&
-         && processed_upto_->pack(cb)                                                // proc_info:ProcessedInfo
+         out_msg_queue_->append_dict_to_bool(cb)   // _ out_queue:OutMsgQueue
-         && cb.append_cellslice_bool(maybe_extra)                                    // extra:(Maybe OutMsgQueueExtra)
+         && processed_upto_->pack(cb)              // proc_info:ProcessedInfo
+         && cb.append_cellslice_bool(maybe_extra)  // extra:(Maybe OutMsgQueueExtra)
          && cb.finalize_to(out_msg_queue_info);
 }
 
@@ -5492,14 +5558,18 @@ bool Collator::create_block_candidate() {
                                  << consensus_config.max_collated_data_size << ")");
   }
   // 4. save block candidate
-  LOG(INFO) << "saving new BlockCandidate";
+  if (mode_ & CollateMode::skip_store_candidate) {
-  td::actor::send_closure_later(
+    td::actor::send_closure_later(actor_id(this), &Collator::return_block_candidate, td::Unit());
-      manager, &ValidatorManager::set_block_candidate, block_candidate->id, block_candidate->clone(),
+  } else {
-      validator_set_->get_catchain_seqno(), validator_set_->get_validator_set_hash(),
+    LOG(INFO) << "saving new BlockCandidate";
-      [self = get_self()](td::Result<td::Unit> saved) -> void {
+    td::actor::send_closure_later(
-        LOG(DEBUG) << "got answer to set_block_candidate";
+        manager, &ValidatorManager::set_block_candidate, block_candidate->id, block_candidate->clone(),
-        td::actor::send_closure_later(std::move(self), &Collator::return_block_candidate, std::move(saved));
+        validator_set_->get_catchain_seqno(), validator_set_->get_validator_set_hash(),
-      });
+        [self = get_self()](td::Result<td::Unit> saved) -> void {
+          LOG(DEBUG) << "got answer to set_block_candidate";
+          td::actor::send_closure_later(std::move(self), &Collator::return_block_candidate, std::move(saved));
+        });
+  }
   // 5. communicate about bad and delayed external messages
   if (!bad_ext_msgs_.empty() || !delay_ext_msgs_.empty()) {
     LOG(INFO) << "sending complete_external_messages() to Manager";
@@ -5643,6 +5713,18 @@ void Collator::after_get_external_messages(td::Result<std::vector<std::pair<Ref<
   check_pending();
 }
 
+/**
+ * Checks if collation was cancelled via cancellation token
+ *
+ * @returns false if the collation was cancelled, true otherwise
+ */
+bool Collator::check_cancelled() {
+  if (cancellation_token_) {
+    return fatal_error(td::Status::Error(ErrorCode::cancelled, "cancelled"));
+  }
+  return true;
+}
+
 td::uint32 Collator::get_skip_externals_queue_size() {
   return SKIP_EXTERNALS_QUEUE_SIZE;
 }

validator/impl/fabric.cpp

@@ -214,16 +214,19 @@ void run_validate_query(ShardIdFull shard, BlockIdExt min_masterchain_block_id,
 void run_collate_query(ShardIdFull shard, const BlockIdExt& min_masterchain_block_id, std::vector<BlockIdExt> prev,
                        Ed25519_PublicKey creator, td::Ref<ValidatorSet> validator_set,
                        td::Ref<CollatorOptions> collator_opts, td::actor::ActorId<ValidatorManager> manager,
-                       td::Timestamp timeout, td::Promise<BlockCandidate> promise) {
+                       td::Timestamp timeout, td::Promise<BlockCandidate> promise,
+                       td::CancellationToken cancellation_token, unsigned mode, int attempt_idx) {
   BlockSeqno seqno = 0;
   for (auto& p : prev) {
     if (p.seqno() > seqno) {
       seqno = p.seqno();
     }
   }
-  td::actor::create_actor<Collator>(PSTRING() << "collate" << shard.to_str() << ":" << (seqno + 1), shard, false,
+  td::actor::create_actor<Collator>(PSTRING() << "collate" << shard.to_str() << ":" << (seqno + 1)
-                                    min_masterchain_block_id, std::move(prev), std::move(validator_set), creator,
+                                              << (attempt_idx ? "_" + td::to_string(attempt_idx) : ""),
-                                    std::move(collator_opts), std::move(manager), timeout, std::move(promise))
+                                    shard, false, min_masterchain_block_id, std::move(prev), std::move(validator_set),
+                                    creator, std::move(collator_opts), std::move(manager), timeout, std::move(promise),
+                                    std::move(cancellation_token), mode, attempt_idx)
       .release();
 }
 
@@ -239,7 +242,7 @@ void run_collate_hardfork(ShardIdFull shard, const BlockIdExt& min_masterchain_b
   td::actor::create_actor<Collator>(PSTRING() << "collate" << shard.to_str() << ":" << (seqno + 1), shard, true,
                                     min_masterchain_block_id, std::move(prev), td::Ref<ValidatorSet>{},
                                     Ed25519_PublicKey{Bits256::zero()}, td::Ref<CollatorOptions>{true},
-                                    std::move(manager), timeout, std::move(promise))
+                                    std::move(manager), timeout, std::move(promise), td::CancellationToken{}, 0, 0)
       .release();
 }
 

validator/manager-disk.cpp

@@ -129,7 +129,7 @@ void ValidatorManagerImpl::sync_complete(td::Promise<td::Unit> promise) {
   Ed25519_PublicKey created_by{td::Bits256::zero()};
   td::as<td::uint32>(created_by.as_bits256().data() + 32 - 4) = ((unsigned)std::time(nullptr) >> 8);
   run_collate_query(shard_id, last_masterchain_block_id_, prev, created_by, val_set, td::Ref<CollatorOptions>{true},
-                    actor_id(this), td::Timestamp::in(10.0), std::move(P));
+                    actor_id(this), td::Timestamp::in(10.0), std::move(P), td::CancellationToken{}, 0);
 }
 
 void ValidatorManagerImpl::validate_fake(BlockCandidate candidate, std::vector<BlockIdExt> prev, BlockIdExt last,

validator/validator-group.cpp

@@ -55,7 +55,7 @@ void ValidatorGroup::generate_block_candidate(
       validator_set_, opts_->get_collator_options(), manager_, td::Timestamp::in(10.0),
       [SelfId = actor_id(this), cache = cached_collated_block_](td::Result<BlockCandidate> R) {
         td::actor::send_closure(SelfId, &ValidatorGroup::generated_block_candidate, std::move(cache), std::move(R));
-      });
+      }, cancellation_token_source_.get_cancellation_token(), /* mode = */ 0);
 }
 
 void ValidatorGroup::generated_block_candidate(std::shared_ptr<CachedCollatedBlock> cache, td::Result<BlockCandidate> R) {
@@ -188,6 +188,7 @@ void ValidatorGroup::accept_block_candidate(td::uint32 round_id, PublicKeyHash s
   prev_block_ids_ = std::vector<BlockIdExt>{next_block_id};
   cached_collated_block_ = nullptr;
   approved_candidates_cache_.clear();
+  cancellation_token_source_.cancel();
 }
 
 void ValidatorGroup::retry_accept_block_query(BlockIdExt block_id, td::Ref<BlockData> block,
@@ -433,6 +434,7 @@ void ValidatorGroup::destroy() {
     delay_action([ses]() mutable { td::actor::send_closure(ses, &validatorsession::ValidatorSession::destroy); },
                  td::Timestamp::in(10.0));
   }
+  cancellation_token_source_.cancel();
   stop();
 }
 

validator/validator-group.hpp

@@ -138,6 +138,7 @@ class ValidatorGroup : public td::actor::Actor {
     std::vector<td::Promise<BlockCandidate>> promises;
   };
   std::shared_ptr<CachedCollatedBlock> cached_collated_block_;
+  td::CancellationTokenSource cancellation_token_source_;
 
   void generated_block_candidate(std::shared_ptr<CachedCollatedBlock> cache, td::Result<BlockCandidate> R);