Broadcast dag block in any condition

[jackzhhuang]

Pull request type

The dag block will not be broadcast if its block info's total difficulty is less than the header of the main, leading to an error: a new block that uses it as its one of parents will fail to be executed until the sync pull it.

  pub fn select_head(&mut self, new_branch: BlockChain) -> Result<()> {
        let executed_block = new_branch.head_block();
        let main_total_difficulty = self.main.get_total_difficulty()?;
        let branch_total_difficulty = new_branch.get_total_difficulty()?;
        let parent_is_main_head = self.is_main_head(&executed_block.header().parent_hash());

        if branch_total_difficulty > main_total_difficulty {
            let (enacted_count, enacted_blocks, retracted_count, retracted_blocks) =
                if !parent_is_main_head {
                    self.find_ancestors_from_accumulator(&new_branch)?
                } else {
                    (1, vec![executed_block.block.clone()], 0, vec![])
                };
            self.main = new_branch;

            self.do_new_head(
                executed_block,
                enacted_count,
                enacted_blocks,
                retracted_count,
                retracted_blocks,
            )?;
        } else {
            //send new branch event
            self.broadcast_new_branch(executed_block);
        }
        Ok(())
    }

The problem is in line: let executed_block = new_branch.head_block();. The executed_block will be the header not the latest mined block. This results that minded block will not be broadcast!

The solution is to broadcast any dag block in any condition. See the modified files.