Custom Benchmark Errors and Override (#9517)

* initial idea

* update benchmark test to frame v2

* fix some errors

* fixes for elec phrag

* fix tests

* update extrinsic time and docs

* fix import

* undo extra changes

* helper function

* wrong way

* Update frame/benchmarking/src/utils.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* doesnt need encode/decode

* fix benchmark return

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/frame/elections-phragmen/src/benchmarking.rs

@@ -21,7 +21,9 @@
 
 use super::*;
 
-use frame_benchmarking::{account, benchmarks, impl_benchmark_test_suite, whitelist};
+use frame_benchmarking::{
+	account, benchmarks, impl_benchmark_test_suite, whitelist, BenchmarkError, BenchmarkResult,
+};
 use frame_support::{dispatch::DispatchResultWithPostInfo, traits::OnInitialize};
 use frame_system::RawOrigin;
 
@@ -332,9 +334,16 @@ benchmarks! {
 		}
 	}
 
+	// We use the max block weight for this extrinsic for now. See below.
+	remove_member_without_replacement {}: {
+		Err(BenchmarkError::Override(
+			BenchmarkResult::from_weight(T::BlockWeights::get().max_block)
+		))?;
+	}
+
 	// -- Root ones
 	#[extra] // this calls into phragmen and consumes a full block for now.
-	remove_member_without_replacement {
+	remove_member_without_replacement_extra {
 		// worse case is when we remove a member and we have no runner as a replacement. This
 		// triggers phragmen again. The only parameter is how many candidates will compete for the
 		// new slot.

substrate/frame/elections-phragmen/src/lib.rs

@@ -474,7 +474,7 @@ pub mod pallet {
 		#[pallet::weight(if *has_replacement {
 			T::WeightInfo::remove_member_with_replacement()
 		} else {
-			T::BlockWeights::get().max_block
+			T::WeightInfo::remove_member_without_replacement()
 		})]
 		pub fn remove_member(
 			origin: OriginFor<T>,

substrate/frame/elections-phragmen/src/weights.rs

@@ -54,6 +54,7 @@ pub trait WeightInfo {
 	fn renounce_candidacy_members() -> Weight;
 	fn renounce_candidacy_runners_up() -> Weight;
 	fn remove_member_with_replacement() -> Weight;
+	fn remove_member_without_replacement() -> Weight;
 	fn remove_member_wrong_refund() -> Weight;
 	fn clean_defunct_voters(v: u32, d: u32, ) -> Weight;
 	fn election_phragmen(c: u32, v: u32, e: u32, ) -> Weight;
@@ -150,6 +151,9 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 			.saturating_add(T::DbWeight::get().reads(5 as Weight))
 			.saturating_add(T::DbWeight::get().writes(5 as Weight))
 	}
+	fn remove_member_without_replacement() -> Weight {
+		T::BlockWeights::get().max_block
+	}
 	// Storage: Elections RunnersUp (r:1 w:0)
 	fn remove_member_wrong_refund() -> Weight {
 		(6_697_000 as Weight)
@@ -282,6 +286,11 @@ impl WeightInfo for () {
 			.saturating_add(RocksDbWeight::get().reads(5 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(5 as Weight))
 	}
+	fn remove_member_without_replacement() -> Weight {
+		(76_153_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(5 as Weight))
+			.saturating_add(RocksDbWeight::get().writes(5 as Weight))
+	}
 	// Storage: Elections RunnersUp (r:1 w:0)
 	fn remove_member_wrong_refund() -> Weight {
 		(6_697_000 as Weight)