Offence implementations can disable offenders independently from slashing (#10201)

* Offence implementations can disable offenders independently from slashing

* Fix build on CI

* Run cargo fmt

* Fixes based on review comments

* Make parameter naming consistent

* Fix migration and some English

* Fix migration - again

* cargo fmt

* Cover 2 new cases with a test

substrate/frame/staking/src/tests.rs

@@ -34,7 +34,7 @@ use sp_runtime::{
 	Perbill, Percent,
 };
 use sp_staking::{
-	offence::{OffenceDetails, OnOffenceHandler},
+	offence::{DisableStrategy, OffenceDetails, OnOffenceHandler},
 	SessionIndex,
 };
 use sp_std::prelude::*;
@@ -2250,6 +2250,7 @@ fn slash_in_old_span_does_not_deselect() {
 			}],
 			&[Perbill::from_percent(0)],
 			1,
+			DisableStrategy::WhenSlashed,
 		);
 
 		// the validator doesn't get chilled again
@@ -2266,6 +2267,7 @@ fn slash_in_old_span_does_not_deselect() {
 			// NOTE: A 100% slash here would clean up the account, causing de-registration.
 			&[Perbill::from_percent(95)],
 			1,
+			DisableStrategy::WhenSlashed,
 		);
 
 		// the validator doesn't get chilled again
@@ -2562,6 +2564,7 @@ fn slashing_nominators_by_span_max() {
 			}],
 			&[Perbill::from_percent(10)],
 			2,
+			DisableStrategy::WhenSlashed,
 		);
 
 		assert_eq!(Balances::free_balance(11), 900);
@@ -2588,6 +2591,7 @@ fn slashing_nominators_by_span_max() {
 			}],
 			&[Perbill::from_percent(30)],
 			3,
+			DisableStrategy::WhenSlashed,
 		);
 
 		// 11 was not further slashed, but 21 and 101 were.
@@ -2609,6 +2613,7 @@ fn slashing_nominators_by_span_max() {
 			}],
 			&[Perbill::from_percent(20)],
 			2,
+			DisableStrategy::WhenSlashed,
 		);
 
 		// 11 was further slashed, but 21 and 101 were not.
@@ -2744,6 +2749,7 @@ fn remove_deferred() {
 			&[OffenceDetails { offender: (11, exposure.clone()), reporters: vec![] }],
 			&[Perbill::from_percent(15)],
 			1,
+			DisableStrategy::WhenSlashed,
 		);
 
 		// fails if empty
@@ -2933,6 +2939,40 @@ fn non_slashable_offence_doesnt_disable_validator() {
 	});
 }
 
+#[test]
+fn slashing_independent_of_disabling_validator() {
+	ExtBuilder::default().build_and_execute(|| {
+		mock::start_active_era(1);
+		assert_eq_uvec!(Session::validators(), vec![11, 21]);
+
+		let exposure_11 = Staking::eras_stakers(Staking::active_era().unwrap().index, &11);
+		let exposure_21 = Staking::eras_stakers(Staking::active_era().unwrap().index, &21);
+
+		let now = Staking::active_era().unwrap().index;
+
+		// offence with no slash associated, BUT disabling
+		on_offence_in_era(
+			&[OffenceDetails { offender: (11, exposure_11.clone()), reporters: vec![] }],
+			&[Perbill::zero()],
+			now,
+			DisableStrategy::Always,
+		);
+
+		// offence that slashes 25% of the bond, BUT not disabling
+		on_offence_in_era(
+			&[OffenceDetails { offender: (21, exposure_21.clone()), reporters: vec![] }],
+			&[Perbill::from_percent(25)],
+			now,
+			DisableStrategy::Never,
+		);
+
+		// the offence for validator 10 was explicitly disabled
+		assert!(is_disabled(10));
+		// whereas validator 20 is explicitly not disabled
+		assert!(!is_disabled(20));
+	});
+}
+
 #[test]
 fn offence_threshold_triggers_new_era() {
 	ExtBuilder::default()
@@ -3595,7 +3635,7 @@ fn offences_weight_calculated_correctly() {
 	ExtBuilder::default().nominate(true).build_and_execute(|| {
 		// On offence with zero offenders: 4 Reads, 1 Write
 		let zero_offence_weight = <Test as frame_system::Config>::DbWeight::get().reads_writes(4, 1);
-		assert_eq!(Staking::on_offence(&[], &[Perbill::from_percent(50)], 0), zero_offence_weight);
+		assert_eq!(Staking::on_offence(&[], &[Perbill::from_percent(50)], 0, DisableStrategy::WhenSlashed), zero_offence_weight);
 
 		// On Offence with N offenders, Unapplied: 4 Reads, 1 Write + 4 Reads, 5 Writes
 		let n_offence_unapplied_weight = <Test as frame_system::Config>::DbWeight::get().reads_writes(4, 1)
@@ -3608,7 +3648,7 @@ fn offences_weight_calculated_correctly() {
 					reporters: vec![],
 				}
 			).collect();
-		assert_eq!(Staking::on_offence(&offenders, &[Perbill::from_percent(50)], 0), n_offence_unapplied_weight);
+		assert_eq!(Staking::on_offence(&offenders, &[Perbill::from_percent(50)], 0, DisableStrategy::WhenSlashed), n_offence_unapplied_weight);
 
 		// On Offence with one offenders, Applied
 		let one_offender = [
@@ -3629,7 +3669,7 @@ fn offences_weight_calculated_correctly() {
 			// `reward_cost` * reporters (1)
 			+ <Test as frame_system::Config>::DbWeight::get().reads_writes(2, 2);
 
-		assert_eq!(Staking::on_offence(&one_offender, &[Perbill::from_percent(50)], 0), one_offence_unapplied_weight);
+		assert_eq!(Staking::on_offence(&one_offender, &[Perbill::from_percent(50)], 0, DisableStrategy::WhenSlashed), one_offence_unapplied_weight);
 	});
 }