GH-46 Fix irreversible mode and simplify fetch_head_branch.

libraries/chain/controller.cpp

@@ -1408,7 +1408,7 @@ struct controller_impl {
 
       bool savanna_transistion_required = false;
       auto mark_branch_irreversible = [&, this](auto& forkdb) {
-         auto branch = savanna ? forkdb.fetch_head_branch( irreversible_block_id, new_lib_num)
+         auto branch = savanna ? forkdb.fetch_head_branch( fork_db_head_or_pending(forkdb)->id(), irreversible_block_id)
                                : forkdb.fetch_branch( fork_db_head_or_pending(forkdb)->id(), new_lib_num );
          try {
             auto should_process = [&](auto& bsp) {

libraries/chain/fork_database.cpp

@@ -135,7 +135,7 @@ namespace eosio::chain {
       void             remove_impl( const block_id_type& id );
       branch_t         fetch_branch_impl( const block_id_type& h, uint32_t trim_after_block_num ) const;
       block_branch_t   fetch_block_branch_impl( const block_id_type& h, uint32_t trim_after_block_num ) const;
-      branch_t         fetch_head_branch_impl( const block_id_type& b, uint32_t trim_after_block_num ) const;
+      branch_t         fetch_head_branch_impl( const block_id_type& h, const block_id_type& b ) const;
       full_branch_t    fetch_full_branch_impl(const block_id_type& h) const;
       bsp_t            search_on_branch_impl( const block_id_type& h, uint32_t block_num, include_root_t include_root ) const;
       bsp_t            search_on_head_branch_impl( uint32_t block_num, include_root_t include_root ) const;
@@ -441,23 +441,21 @@ namespace eosio::chain {
 
    template <class BSP>
    fork_database_t<BSP>::branch_t
-   fork_database_t<BSP>::fetch_head_branch(const block_id_type& b, uint32_t trim_after_block_num) const {
+   fork_database_t<BSP>::fetch_head_branch(const block_id_type& h, const block_id_type& b) const {
       std::lock_guard g(my->mtx);
-      return my->fetch_head_branch_impl(b, trim_after_block_num);
+      return my->fetch_head_branch_impl(h, b);
    }
 
    template <class BSP>
    fork_database_t<BSP>::branch_t
-   fork_database_impl<BSP>::fetch_head_branch_impl(const block_id_type& b, uint32_t trim_after_block_num) const {
+   fork_database_impl<BSP>::fetch_head_branch_impl(const block_id_type& h, const block_id_type& b) const {
       branch_t result;
-      if (!head)
-         return result;
       result.reserve(index.size());
       bool found_branch = false;
-      for (auto i = index.find(head->id()); i != index.end(); i = index.find((*i)->previous())) {
+      for (auto i = index.find(h); i != index.end(); i = index.find((*i)->previous())) {
          if ((*i)->id() == b)
             found_branch = true;
-         if (found_branch && (*i)->block_num() <= trim_after_block_num)
+         if (found_branch)
             result.push_back(*i);
       }
       return result;

libraries/chain/include/eosio/chain/fork_database.hpp

@@ -97,9 +97,11 @@ namespace eosio::chain {
       block_branch_t fetch_block_branch( const block_id_type& h, uint32_t trim_after_block_num = std::numeric_limits<uint32_t>::max() ) const;
 
       /**
-       * Similar to fetch_branch but only returns up to head or empty if b not on head branch.
+       * Returns the sequence of block states resulting from trimming the branch from the
+       * root block (exclusive) to the block with an id of `h` (inclusive) by removing any
+       * block states that are after block `b`. Returns empty if `b` not found on `h` branch.
        */
-      branch_t fetch_head_branch( const block_id_type& b, uint32_t trim_after_block_num = std::numeric_limits<uint32_t>::max() ) const;
+      branch_t fetch_head_branch( const block_id_type& h, const block_id_type& b ) const;
 
       /**
        *  Returns full branch of block_header_state pointers including the root.

unittests/fork_db_tests.cpp

@@ -121,9 +121,9 @@ BOOST_AUTO_TEST_CASE(add_remove_test) try {
    BOOST_TEST(forkdb.head()->id() == root->id());
    forkdb.mark_valid(bsp13a);
    BOOST_TEST(forkdb.head()->id() == bsp13a->id());
-   branch = forkdb.fetch_head_branch(bsp11c->id());
+   branch = forkdb.fetch_head_branch(forkdb.head()->id(), bsp11c->id());
    BOOST_TEST(branch.empty()); // bsp11c not on bsp13a branch
-   branch = forkdb.fetch_head_branch(bsp12a->id());
+   branch = forkdb.fetch_head_branch(forkdb.head()->id(), bsp12a->id());
    BOOST_REQUIRE(branch.size() == 2);
    BOOST_TEST(branch[0] == bsp12a);
    BOOST_TEST(branch[1] == bsp11a);