From 919fd84b7824654ebfa6f77284d4ee68f53a271b Mon Sep 17 00:00:00 2001
From: Antioch Peverell <apeverell@protonmail.com>
Date: Mon, 3 Dec 2018 22:27:03 +0000
Subject: [PATCH] cleanup unnecessary reset_head calls (#2072)

---
 chain/src/chain.rs                   | 19 ++-----------------
 chain/src/store.rs                   |  8 ++++----
 servers/src/common/adapters.rs       | 15 ++-------------
 servers/src/grin/sync/header_sync.rs |  3 ---
 servers/src/grin/sync/syncer.rs      |  2 --
 5 files changed, 8 insertions(+), 39 deletions(-)

diff --git a/chain/src/chain.rs b/chain/src/chain.rs
index 878b670c0..ef7cb086e 100644
--- a/chain/src/chain.rs
+++ b/chain/src/chain.rs
@@ -1014,14 +1014,6 @@ impl Chain {
 		self.orphans.len()
 	}
 
-	/// Reset header_head and sync_head to head of current body chain
-	pub fn reset_head(&self) -> Result<(), Error> {
-		let batch = self.store.batch()?;
-		batch.reset_head()?;
-		batch.commit()?;
-		Ok(())
-	}
-
 	/// Tip (head) of the block chain.
 	pub fn head(&self) -> Result<Tip, Error> {
 		self.store
@@ -1159,14 +1151,6 @@ impl Chain {
 			.block_exists(&h)
 			.map_err(|e| ErrorKind::StoreErr(e, "chain block exists".to_owned()).into())
 	}
-
-	/// Reset sync_head to the provided head.
-	pub fn reset_sync_head(&self, head: &Tip) -> Result<(), Error> {
-		let batch = self.store.batch()?;
-		batch.save_sync_head(head)?;
-		batch.commit()?;
-		Ok(())
-	}
 }
 
 fn setup_head(
@@ -1296,7 +1280,8 @@ fn setup_head(
 			head.last_block_h,
 			head.height,
 		);
-		batch.reset_head()?;
+		batch.reset_header_head()?;
+		batch.reset_sync_head()?;
 	}
 
 	batch.commit()?;
diff --git a/chain/src/store.rs b/chain/src/store.rs
index 060b94e26..4a0caa0ee 100644
--- a/chain/src/store.rs
+++ b/chain/src/store.rs
@@ -175,16 +175,16 @@ impl<'a> Batch<'a> {
 		self.db.put_ser(&vec![SYNC_HEAD_PREFIX], t)
 	}
 
+	/// Reset sync_head to the current head of the header chain.
 	pub fn reset_sync_head(&self) -> Result<(), Error> {
 		let head = self.header_head()?;
 		self.save_sync_head(&head)
 	}
 
-	// Reset both header_head and sync_head to the current head of the body chain
-	pub fn reset_head(&self) -> Result<(), Error> {
+	/// Reset header_head to the current head of the body chain.
+	pub fn reset_header_head(&self) -> Result<(), Error> {
 		let tip = self.head()?;
-		self.save_header_head(&tip)?;
-		self.save_sync_head(&tip)
+		self.save_header_head(&tip)
 	}
 
 	/// get block
diff --git a/servers/src/common/adapters.rs b/servers/src/common/adapters.rs
index 0550500b3..b4f69a3cf 100644
--- a/servers/src/common/adapters.rs
+++ b/servers/src/common/adapters.rs
@@ -215,11 +215,6 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 		if let &Err(ref e) = &res {
 			debug!("Block header {} refused by chain: {:?}", bhash, e.kind());
 			if e.is_bad_data() {
-				debug!(
-					"header_received: {} is a bad header, resetting header head",
-					bhash
-				);
-				let _ = self.chain().reset_head();
 				return false;
 			} else {
 				// we got an error when trying to process the block header
@@ -444,13 +439,7 @@ impl NetToChainAdapter {
 				true
 			}
 			Err(ref e) if e.is_bad_data() => {
-				debug!("process_block: {} is a bad block, resetting head", bhash);
-				let _ = self.chain().reset_head();
-
-				// we potentially changed the state of the system here
-				// so check everything is still ok
 				self.validate_chain(bhash);
-
 				false
 			}
 			Err(e) => {
@@ -486,9 +475,9 @@ impl NetToChainAdapter {
 		// We are out of consensus at this point and want to track the problem
 		// down as soon as possible.
 		// Skip this if we are currently syncing (too slow).
-		if self.chain().head().unwrap().height > 0
+		if self.config.chain_validation_mode == ChainValidationMode::EveryBlock
+			&& self.chain().head().unwrap().height > 0
 			&& !self.sync_state.is_syncing()
-			&& self.config.chain_validation_mode == ChainValidationMode::EveryBlock
 		{
 			let now = Instant::now();
 
diff --git a/servers/src/grin/sync/header_sync.rs b/servers/src/grin/sync/header_sync.rs
index b5e239322..890314fd2 100644
--- a/servers/src/grin/sync/header_sync.rs
+++ b/servers/src/grin/sync/header_sync.rs
@@ -66,9 +66,6 @@ impl HeaderSync {
 					header_head.height,
 				);
 
-				// Reset sync_head to the same as current header_head.
-				self.chain.reset_sync_head(&header_head).unwrap();
-
 				// Rebuild the sync MMR to match our updated sync_head.
 				self.chain.rebuild_sync_mmr(&header_head).unwrap();
 
diff --git a/servers/src/grin/sync/syncer.rs b/servers/src/grin/sync/syncer.rs
index 3f6496c8f..5b09e556e 100644
--- a/servers/src/grin/sync/syncer.rs
+++ b/servers/src/grin/sync/syncer.rs
@@ -198,8 +198,6 @@ impl SyncRunner {
 					ch.height,
 					ch.last_block_h
 				);
-
-				let _ = self.chain.reset_head();
 				is_syncing = false;
 			}
 		} else {