From 461b2d48531bac522ddb0b7eb532ebb70427f7d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Drwi=C4=99ga?= <tomusdrw@users.noreply.github.com>
Date: Thu, 19 Apr 2018 11:25:15 +0200
Subject: [PATCH] Fix receipts stripping. (#8414)

---
 ethcore/src/block.rs         | 28 ++++++++++++++++++----------
 ethcore/src/client/client.rs | 13 ++++++++++---
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/ethcore/src/block.rs b/ethcore/src/block.rs
index e3622c293..d9f3d27af 100644
--- a/ethcore/src/block.rs
+++ b/ethcore/src/block.rs
@@ -491,6 +491,24 @@ impl ClosedBlock {
 }
 
 impl LockedBlock {
+
+	/// Removes outcomes from receipts and updates the receipt root.
+	///
+	/// This is done after the block is enacted for historical reasons.
+	/// We allow inconsistency in receipts for some chains if `validate_receipts_transition`
+	/// is set to non-zero value, so the check only happens if we detect
+	/// unmatching root first and then fall back to striped receipts.
+	pub fn strip_receipts_outcomes(&mut self) {
+		for receipt in &mut self.block.receipts {
+			receipt.outcome = TransactionOutcome::Unknown;
+		}
+		self.block.header.set_receipts_root(
+			ordered_trie_root(self.block.receipts.iter().map(|r| r.rlp_bytes()))
+		);
+		// compute hash and cache it.
+		self.block.header.compute_hash();
+	}
+
 	/// Get the hash of the header without seal arguments.
 	pub fn hash(&self) -> H256 { self.header().bare_hash() }
 
@@ -570,7 +588,6 @@ fn enact(
 	last_hashes: Arc<LastHashes>,
 	factories: Factories,
 	is_epoch_begin: bool,
-	strip_receipts: bool,
 ) -> Result<LockedBlock, Error> {
 	{
 		if ::log::max_log_level() >= ::log::LogLevel::Trace {
@@ -600,12 +617,6 @@ fn enact(
 		b.push_uncle(u)?;
 	}
 
-	if strip_receipts {
-		for receipt in &mut b.block.receipts {
-			receipt.outcome = TransactionOutcome::Unknown;
-		}
-	}
-
 	Ok(b.close_and_lock())
 }
 
@@ -619,8 +630,6 @@ pub fn enact_verified(
 	last_hashes: Arc<LastHashes>,
 	factories: Factories,
 	is_epoch_begin: bool,
-	// Remove state root from transaction receipts to make them EIP-98 compatible.
-	strip_receipts: bool,
 ) -> Result<LockedBlock, Error> {
 	let view = view!(BlockView, &block.bytes);
 
@@ -635,7 +644,6 @@ pub fn enact_verified(
 		last_hashes,
 		factories,
 		is_epoch_begin,
-		strip_receipts,
 	)
 }
 
diff --git a/ethcore/src/client/client.rs b/ethcore/src/client/client.rs
index d2b63b6cd..bb7f5894b 100644
--- a/ethcore/src/client/client.rs
+++ b/ethcore/src/client/client.rs
@@ -415,7 +415,6 @@ impl Importer {
 		let db = client.state_db.read().boxed_clone_canon(header.parent_hash());
 
 		let is_epoch_begin = chain.epoch_transition(parent.number(), *header.parent_hash()).is_some();
-		let strip_receipts = header.number() < engine.params().validate_receipts_transition;
 		let enact_result = enact_verified(
 			block,
 			engine,
@@ -425,13 +424,21 @@ impl Importer {
 			last_hashes,
 			client.factories.clone(),
 			is_epoch_begin,
-			strip_receipts,
 		);
 
-		let locked_block = enact_result.map_err(|e| {
+		let mut locked_block = enact_result.map_err(|e| {
 			warn!(target: "client", "Block import failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
 		})?;
 
+		// Strip receipts for blocks before validate_receipts_transition,
+		// if the expected receipts root header does not match.
+		// (i.e. allow inconsistency in receipts outcome before the transition block)
+		if header.number() < engine.params().validate_receipts_transition
+			&& header.receipts_root() != locked_block.block().header().receipts_root()
+		{
+			locked_block.strip_receipts_outcomes();
+		}
+
 		// Final Verification
 		if let Err(e) = self.verifier.verify_block_final(&header, locked_block.block().header()) {
 			warn!(target: "client", "Stage 5 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);