Fix block detail updating (#11015)

* Add finality parameter to `null engine`

* Add testcase for finalization marking in `ethcore` client

* Add double cache read for db

* Prevent lost update of block details

* Read with pending update for block details in batch

ethcore/engines/null-engine/src/lib.rs

@@ -27,19 +27,26 @@ use machine::{
 	ExecutedBlock,
 	Machine,
 };
-use common_types::snapshot::Snapshotting;
+use common_types::{
+	ancestry_action::AncestryAction,
+	header::ExtendedHeader,
+	snapshot::Snapshotting
+};
 
 /// Params for a null engine.
 #[derive(Clone, Default)]
 pub struct NullEngineParams {
 	/// base reward for a block.
 	pub block_reward: U256,
+	/// Immediate finalization.
+	pub immediate_finalization: bool
 }
 
 impl From<ethjson::spec::NullEngineParams> for NullEngineParams {
 	fn from(p: ethjson::spec::NullEngineParams) -> Self {
 		NullEngineParams {
 			block_reward: p.block_reward.map_or_else(Default::default, Into::into),
+			immediate_finalization: p.immediate_finalization.unwrap_or(false)
 		}
 	}
 }
@@ -108,4 +115,13 @@ impl Engine for NullEngine {
 	fn params(&self) -> &CommonParams {
 		self.machine.params()
 	}
+
+	fn ancestry_actions(&self, _header: &Header, ancestry: &mut dyn Iterator<Item=ExtendedHeader>) -> Vec<AncestryAction> {
+		if self.params.immediate_finalization {
+			// always mark parent finalized
+			ancestry.take(1).map(|e| AncestryAction::MarkFinalized(e.header.hash())).collect()
+		} else {
+			Vec::new()
+		}
+	}
 }