Transaction fee distribution:

Introduced BlockAuthorOption:
Engines are now able to specify who is the block author via  BlockAuthorOption::EngineBlockAuthor(Address),

Author: SurfingNerd

crates/ethcore/src/engines/hbbft/hbbft_engine.rs

@@ -11,7 +11,8 @@ use crate::{
         traits::{EngineClient, ForceUpdateSealing},
     },
     engines::{
-        Engine, EngineError, ForkChoice, Seal, SealingState, default_system_or_code_call,
+        BlockAuthorOption, Engine, EngineError, ForkChoice, Seal, SealingState,
+        default_system_or_code_call,
         hbbft::{
             contracts::random_hbbft::set_current_seed_tx_raw, hbbft_message_memorium::BadSealReason,
         },
@@ -595,14 +596,9 @@ impl HoneyBadgerBFT {
             .write()
             .insert(batch.epoch, random_number);
 
-        if let Some(mut header) = client.create_pending_block_at(batch_txns, timestamp, batch.epoch) {
+        if let Some(header) = client.create_pending_block_at(batch_txns, timestamp, batch.epoch) {
             let block_num = header.number();
             let hash = header.bare_hash();
-            if let Some(reward_contract_address) = self.params.block_reward_contract_address  {
-                header.set_author(reward_contract_address);    
-            } else {
-                warn!("Creating block with no blockRewardContractAddress {}", block_num);
-            }
             // TODO: trace is missleading here: we already got the signature shares, we can already
             trace!(target: "consensus", "Sending signature share of {} for block {}", hash, block_num);
             let step = match self
@@ -795,7 +791,7 @@ impl HoneyBadgerBFT {
             .map(|msg| msg.map(|m| Message::Sealing(block_num, m)));
         self.dispatch_messages(&client, messages, network_info);
         if let Some(sig) = step.output.into_iter().next() {
-            trace!(target: "consensus", "Signature for block {} is ready", block_num);
+            trace!(target: "consensus", "Signature for block {} is ready.", block_num);
             let state = Sealing::Complete(sig);
             self.sealing.write().insert(block_num, state);
 
@@ -1473,8 +1469,11 @@ impl Engine<EthereumMachine> for HoneyBadgerBFT {
         false
     }
 
-    fn use_block_author(&self) -> bool {
-        true
+    fn use_block_author(&self) -> BlockAuthorOption {
+        if let Some(address) = self.params.block_reward_contract_address {
+            return BlockAuthorOption::EngineBlockAuthor(address);
+        }
+        return BlockAuthorOption::ConfiguredBlockAuthor;
     }
 
     fn on_before_transactions(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
@@ -1542,7 +1541,7 @@ impl Engine<EthereumMachine> for HoneyBadgerBFT {
 
     /// Allow mutating the header during seal generation.
     fn on_seal_block(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
-       let random_numbers = self.random_numbers.read();
+        let random_numbers = self.random_numbers.read();
         match random_numbers.get(&block.header.number()) {
             None => {
                 warn!("No rng value available for header.");
@@ -1563,7 +1562,6 @@ impl Engine<EthereumMachine> for HoneyBadgerBFT {
         if let Some(address) = self.params.block_reward_contract_address {
             // only if no block reward skips are defined for this block.
             let header_number = block.header.number();
-            block.header.set_author(address);
 
             if self
                 .params

crates/ethcore/src/engines/mod.rs

@@ -305,6 +305,18 @@ pub enum EpochChange<M: Machine> {
     Yes(Proof<M>),
 }
 
+/// who shall author a new Block ?
+pub enum BlockAuthorOption {
+    /// use the Zero address as block author.
+    ZeroBlockAuthor,
+
+    /// use the block author from the config.
+    ConfiguredBlockAuthor,
+
+    /// use the block author provivided by the EngineClient.
+    EngineBlockAuthor(Address),
+}
+
 /// A consensus mechanism for the chain. Generally either proof-of-work or proof-of-stake-based.
 /// Provides hooks into each of the major parts of block import.
 pub trait Engine<M: Machine>: Sync + Send {
@@ -581,8 +593,8 @@ pub trait Engine<M: Machine>: Sync + Send {
     }
 
     /// Use the author as signer as well as block author.
-    fn use_block_author(&self) -> bool {
-        true
+    fn use_block_author(&self) -> BlockAuthorOption {
+        BlockAuthorOption::ConfiguredBlockAuthor
     }
 
     /// allows engines to define a block that should not get pruned in the DB.

crates/ethcore/src/miner/miner.rs

@@ -463,10 +463,10 @@ impl Miner {
         let params = self.params.read().clone();
 
         let block = match chain.prepare_open_block(
-            if self.engine.use_block_author() {
-                params.author
-            } else {
-                Address::zero()
+            match self.engine.use_block_author() {
+                crate::engines::BlockAuthorOption::ZeroBlockAuthor => Address::zero(),
+                crate::engines::BlockAuthorOption::ConfiguredBlockAuthor => params.author,
+                crate::engines::BlockAuthorOption::EngineBlockAuthor(address) => address,
             },
             params.gas_range_target,
             params.extra_data,