GH-6 Revert back to flat_map for simpler and not storing unneeded imp…

…lementation

libraries/chain/block_header_state.cpp

@@ -106,23 +106,18 @@ void finish_next(const block_header_state& prev,
    if (!prev.proposer_policies.empty()) {
       auto it = prev.proposer_policies.begin();
       // +1 since this is called after the block is built, this will be the active schedule for the next block
-      while (it != prev.proposer_policies.end() && it->first.slot <= next_header_state.header.timestamp.slot + 1) {
+      if (it->first.slot <= next_header_state.header.timestamp.slot + 1) {
          next_header_state.active_proposer_policy = it->second;
-         ++it;
-      }
-      if (it == prev.proposer_policies.begin()) { // none made active
+         next_header_state.proposer_policies = { ++it, prev.proposer_policies.end() };
+      } else {
          next_header_state.proposer_policies = prev.proposer_policies;
-      } else if (it != prev.proposer_policies.end()) { // some made active
-         next_header_state.proposer_policies = { it, prev.proposer_policies.end() };
-      } else { // all made active
-         // next_header_state.proposer_policies will be emtpy
       }
    }
 
    if (if_ext.new_proposer_policy) {
       // called when assembling the block
-      next_header_state.proposer_policies.emplace_back(if_ext.new_proposer_policy->active_time,
-                                                       std::move(if_ext.new_proposer_policy));
+      next_header_state.proposer_policies[if_ext.new_proposer_policy->active_time] =
+         std::move(if_ext.new_proposer_policy);
    }
 
    // finality_core

libraries/chain/controller.cpp

@@ -507,7 +507,7 @@ struct building_block {
 
          const producer_authority_schedule& lhs = get_next_sched();
 
-         decltype(lhs.version) v = lhs.version;
+         auto v = lhs.version;
 
          if (!std::ranges::equal(lhs.producers, producers)) {
             ++v;

libraries/chain/include/eosio/chain/block_header_state.hpp

@@ -68,18 +68,13 @@ struct block_header_state {
    finalizer_policy_ptr                active_finalizer_policy; // finalizer set + threshold + generation, supports `digest()`
    proposer_policy_ptr                 active_proposer_policy;  // producer authority schedule, supports `digest()`
 
-   // <block time when proposer_policy will become active, proposer policy>
+   // block time when proposer_policy will become active
+   // current algorithm only two entries possible, for for the next,next round and one for block round after that
    // The active time is the next,next producer round. For example,
    //   round A [1,2,..12], next_round B [1,2,..12], next_next_round C [1,2,..12], D [1,2,..12]
    //   If proposed in A1, A2, .. A12 becomes active in C1
    //   If proposed in B1, B2, .. B12 becomes active in D1
-   // This is a `deque` because the same active block time can contain up to 12 entries (one per block)
-   // for the entry proposed in a block:
-   //   For example, proposer policy proposed: P1 in A1, P2 in A7, P3 in A12, P4 in B2, P5 in B12 then the map contains:
-   //       [C1 -> P1],[C1 -> P2],[C1 -> P3],[D1 -> P4],[D1 -> P5]
-   //   At C1 P1,P2,P3 are applied causing an active policy of P3
-   //   At D1 P4,P5 are appliced causing an acive policy of P5
-   std::deque<std::pair<block_timestamp_type, proposer_policy_ptr>> proposer_policies;
+   flat_map<block_timestamp_type, proposer_policy_ptr>     proposer_policies;
 
    // track in-flight finalizer policies. This is a `multimap` because the same block number
    // can hold a `proposed` and a `pending` finalizer_policy. When that block becomes final, the

libraries/chain/include/eosio/chain/snapshot_detail.hpp

@@ -116,7 +116,7 @@ namespace eosio::chain::snapshot_detail {
       finality_core                                       core;
       finalizer_policy_ptr                                active_finalizer_policy;
       proposer_policy_ptr                                 active_proposer_policy;
-      std::deque<std::pair<block_timestamp_type, proposer_policy_ptr>> proposer_policies;
+      flat_map<block_timestamp_type, proposer_policy_ptr> proposer_policies;
       flat_multimap<block_num_type, finalizer_policy_tracker> finalizer_policies;
       uint32_t                                            finalizer_policy_generation;