dapp staking v3 - Freeze Improvements

pallets/collator-selection/Cargo.toml

@@ -59,6 +59,7 @@ std = [
 	"pallet-authorship/std",
 	"pallet-session/std",
 	"pallet-aura/std",
+	"pallet-balances/std",
 ]
 
 try-runtime = ["frame-support/try-runtime"]

pallets/collator-selection/src/lib.rs

@@ -109,6 +109,12 @@ pub mod pallet {
         }
     }
 
+    /// Used to check whether an account is allowed to be a candidate.
+    pub trait AccountCheck<AccountId> {
+        /// `true` if the account is allowed to be a candidate, `false` otherwise.
+        fn allowed_candidacy(account: &AccountId) -> bool;
+    }
+
     /// Configure the pallet by specifying the parameters and types on which it depends.
     #[pallet::config]
     pub trait Config: frame_system::Config {
@@ -157,6 +163,9 @@ pub mod pallet {
         /// How many in perc kicked collators should be slashed (set 0 to disable)
         type SlashRatio: Get<Perbill>;
 
+        /// Used to check whether an account is allowed to be a candidate.
+        type AccountCheck: AccountCheck<Self::AccountId>;
+
         /// The weight information of this pallet.
         type WeightInfo: WeightInfo;
     }
@@ -287,6 +296,8 @@ pub mod pallet {
         NoAssociatedValidatorId,
         /// Validator ID is not yet registered
         ValidatorNotRegistered,
+        /// Account is now allowed to be a candidate due to an external reason (e.g. it might be participating in dApp staking)
+        NotAllowedCandidate,
     }
 
     #[pallet::hooks]
@@ -375,6 +386,10 @@ pub mod pallet {
                 !Self::invulnerables().contains(&who),
                 Error::<T>::AlreadyInvulnerable
             );
+            ensure!(
+                T::AccountCheck::allowed_candidacy(&who),
+                Error::<T>::NotAllowedCandidate
+            );
 
             let validator_key = T::ValidatorIdOf::convert(who.clone())
                 .ok_or(Error::<T>::NoAssociatedValidatorId)?;
@@ -502,6 +517,11 @@ pub mod pallet {
                 })
                 .collect::<Vec<_>>()
         }
+
+        /// Check whether an account is a candidate.
+        pub fn is_account_candidate(account: &T::AccountId) -> bool {
+            Self::candidates().iter().any(|c| &c.who == account)
+        }
     }
 
     /// Keep track of number of authored blocks per authority, uncles are counted as well since

pallets/collator-selection/src/mock.rs

@@ -212,6 +212,15 @@ impl ValidatorRegistration<u64> for IsRegistered {
     }
 }
 
+pub(crate) const BLACKLISTED_ACCOUNT: u64 = 987654321;
+
+pub struct DummyAccountCheck;
+impl AccountCheck<u64> for DummyAccountCheck {
+    fn allowed_candidacy(account: &u64) -> bool {
+        *account != BLACKLISTED_ACCOUNT
+    }
+}
+
 impl Config for Test {
     type RuntimeEvent = RuntimeEvent;
     type Currency = Balances;
@@ -225,6 +234,7 @@ impl Config for Test {
     type ValidatorIdOf = IdentityCollator;
     type ValidatorRegistration = IsRegistered;
     type SlashRatio = SlashRatio;
+    type AccountCheck = DummyAccountCheck;
     type WeightInfo = ();
 }
 

pallets/collator-selection/src/tests.rs

@@ -214,6 +214,16 @@ fn cannot_register_as_candidate_if_poor() {
     });
 }
 
+#[test]
+fn cannot_register_candidate_if_externally_blacklisted() {
+    new_test_ext().execute_with(|| {
+        assert_noop!(
+            CollatorSelection::register_as_candidate(RuntimeOrigin::signed(BLACKLISTED_ACCOUNT)),
+            Error::<Test>::NotAllowedCandidate,
+        );
+    })
+}
+
 #[test]
 fn register_as_candidate_works() {
     new_test_ext().execute_with(|| {