From ec85145f5950fb1eb64204920135648fb8e8a1a6 Mon Sep 17 00:00:00 2001
From: tgmichel <telmo@purestake.com>
Date: Tue, 22 Nov 2022 00:38:48 +0100
Subject: [PATCH] Fix gas used ratio (#898)

---
 client/rpc/src/eth/cache/mod.rs    | 31 ++++--------------------------
 ts-tests/tests/test-fee-history.ts |  2 +-
 2 files changed, 5 insertions(+), 28 deletions(-)

diff --git a/client/rpc/src/eth/cache/mod.rs b/client/rpc/src/eth/cache/mod.rs
index 8096247a7de32..d81b0327918bf 100644
--- a/client/rpc/src/eth/cache/mod.rs
+++ b/client/rpc/src/eth/cache/mod.rs
@@ -309,15 +309,13 @@ where
 		fee_history_cache: FeeHistoryCache,
 		block_limit: u64,
 	) {
-		use sp_runtime::Permill;
-
 		struct TransactionHelper {
 			gas_used: u64,
 			effective_reward: u64,
 		}
 		// Calculates the cache for a single block
 		#[rustfmt::skip]
-			let fee_history_cache_item = |hash: H256, elasticity: Permill| -> (
+			let fee_history_cache_item = |hash: H256| -> (
 			FeeHistoryCacheItem,
 			Option<u64>
 		) {
@@ -360,17 +358,9 @@ where
 			};
 			if let (Some(block), Some(receipts)) = (block, receipts) {
 				block_number = Some(block.header.number.as_u64());
-				// Calculate the gas used ratio.
-				// TODO this formula needs the pallet-base-fee configuration.
-				// By now we assume just the default 0.125 (elasticity multiplier 8).
 				let gas_used = block.header.gas_used.as_u64() as f64;
 				let gas_limit = block.header.gas_limit.as_u64() as f64;
-				let elasticity_multiplier: f64 = (elasticity / Permill::from_parts(1_000_000))
-					.deconstruct()
-					.into();
-				let gas_target = gas_limit / elasticity_multiplier;
-
-				result.gas_used_ratio = gas_used / (gas_target * elasticity_multiplier);
+				result.gas_used_ratio = gas_used / gas_limit;
 
 				let mut previous_cumulative_gas = U256::zero();
 				let used_gas = |current: U256, previous: &mut U256| -> u64 {
@@ -449,19 +439,6 @@ where
 
 		while let Some(notification) = notification_st.next().await {
 			if notification.is_new_best {
-				let hash = notification.hash;
-				let id = BlockId::Hash(hash);
-				let schema = frontier_backend_client::onchain_storage_schema::<B, C, BE>(
-					client.as_ref(),
-					id,
-				);
-				let handler = overrides
-					.schemas
-					.get(&schema)
-					.unwrap_or(&overrides.fallback);
-
-				let default_elasticity = Permill::from_parts(125_000);
-				let elasticity = handler.elasticity(&id).unwrap_or(default_elasticity);
 				// In case a re-org happened on import.
 				if let Some(tree_route) = notification.tree_route {
 					if let Ok(fee_history_cache) = &mut fee_history_cache.lock() {
@@ -475,13 +452,13 @@ where
 						// Insert enacted.
 						let _ = tree_route.enacted().iter().map(|hash_and_number| {
 							let (result, block_number) =
-								fee_history_cache_item(hash_and_number.hash, elasticity);
+								fee_history_cache_item(hash_and_number.hash);
 							commit_if_any(result, block_number);
 						});
 					}
 				}
 				// Cache the imported block.
-				let (result, block_number) = fee_history_cache_item(hash, elasticity);
+				let (result, block_number) = fee_history_cache_item(notification.hash);
 				commit_if_any(result, block_number);
 			}
 		}
diff --git a/ts-tests/tests/test-fee-history.ts b/ts-tests/tests/test-fee-history.ts
index fce8908171d4b..2677d39ab7503 100644
--- a/ts-tests/tests/test-fee-history.ts
+++ b/ts-tests/tests/test-fee-history.ts
@@ -74,7 +74,7 @@ describeWithFrontier("Frontier RPC (Fee History)", (context) => {
 		// baseFeePerGas is always the requested block range + 1 (the next derived base fee).
 		expect(result.baseFeePerGas.length).to.be.eq(blockCount + 1);
 		// gasUsedRatio for the requested block range.
-		expect(result.gasUsedRatio.length).to.be.eq(blockCount);
+		expect(result.gasUsedRatio).to.be.deep.eq(Array(blockCount).fill(0.03575712));
 		// two-dimensional reward list for the requested block range.
 		expect(result.reward.length).to.be.eq(blockCount);
 		// each block has a reward list which's size is the requested percentile list.