[Identity] Decouple usernames from identities

cumulus/parachains/runtimes/people/people-rococo/src/people.rs

@@ -36,6 +36,7 @@ parameter_types! {
 	//   17 | Min size without `IdentityInfo` (accounted for in byte deposit)
 	pub const BasicDeposit: Balance = deposit(1, 17);
 	pub const ByteDeposit: Balance = deposit(0, 1);
+	pub const UsernameDeposit: Balance = deposit(0, 32);
 	pub const SubAccountDeposit: Balance = deposit(1, 53);
 	pub RelayTreasuryAccount: AccountId =
 		parachains_common::TREASURY_PALLET_ID.into_account_truncating();
@@ -46,6 +47,7 @@ impl pallet_identity::Config for Runtime {
 	type Currency = Balances;
 	type BasicDeposit = BasicDeposit;
 	type ByteDeposit = ByteDeposit;
+	type UsernameDeposit = UsernameDeposit;
 	type SubAccountDeposit = SubAccountDeposit;
 	type MaxSubAccounts = ConstU32<100>;
 	type IdentityInformation = IdentityInfo;
@@ -57,6 +59,7 @@ impl pallet_identity::Config for Runtime {
 	type SigningPublicKey = <Signature as Verify>::Signer;
 	type UsernameAuthorityOrigin = EnsureRoot<Self::AccountId>;
 	type PendingUsernameExpiration = ConstU32<{ 7 * DAYS }>;
+	type UsernameGracePeriod = ConstU32<{ 3 * DAYS }>;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = weights::pallet_identity::WeightInfo<Runtime>;

cumulus/parachains/runtimes/people/people-rococo/src/weights/pallet_identity.rs

@@ -340,7 +340,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	/// Proof: `Identity::AccountOfUsername` (`max_values`: None, `max_size`: Some(73), added: 2548, mode: `MaxEncodedLen`)
 	/// Storage: `Identity::IdentityOf` (r:1 w:1)
 	/// Proof: `Identity::IdentityOf` (`max_values`: None, `max_size`: Some(7572), added: 10047, mode: `MaxEncodedLen`)
-	fn set_username_for() -> Weight {
+	fn set_username_for(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `80`
 		//  Estimated: `11037`
@@ -368,7 +368,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	}
 	/// Storage: `Identity::PendingUsernames` (r:1 w:1)
 	/// Proof: `Identity::PendingUsernames` (`max_values`: None, `max_size`: Some(77), added: 2552, mode: `MaxEncodedLen`)
-	fn remove_expired_approval() -> Weight {
+	fn remove_expired_approval(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `106`
 		//  Estimated: `3542`
@@ -406,4 +406,13 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	fn unbind_username() -> Weight {
+		Weight::zero()
+	}
+	fn remove_username() -> Weight {
+		Weight::zero()
+	}
+	fn kill_username(_p: u32, ) -> Weight {
+		Weight::zero()
+	}
 }

cumulus/parachains/runtimes/people/people-westend/src/people.rs

@@ -36,6 +36,7 @@ parameter_types! {
 	//   17 | Min size without `IdentityInfo` (accounted for in byte deposit)
 	pub const BasicDeposit: Balance = deposit(1, 17);
 	pub const ByteDeposit: Balance = deposit(0, 1);
+	pub const UsernameDeposit: Balance = deposit(0, 32);
 	pub const SubAccountDeposit: Balance = deposit(1, 53);
 	pub RelayTreasuryAccount: AccountId =
 		parachains_common::TREASURY_PALLET_ID.into_account_truncating();
@@ -46,6 +47,7 @@ impl pallet_identity::Config for Runtime {
 	type Currency = Balances;
 	type BasicDeposit = BasicDeposit;
 	type ByteDeposit = ByteDeposit;
+	type UsernameDeposit = UsernameDeposit;
 	type SubAccountDeposit = SubAccountDeposit;
 	type MaxSubAccounts = ConstU32<100>;
 	type IdentityInformation = IdentityInfo;
@@ -57,6 +59,7 @@ impl pallet_identity::Config for Runtime {
 	type SigningPublicKey = <Signature as Verify>::Signer;
 	type UsernameAuthorityOrigin = EnsureRoot<Self::AccountId>;
 	type PendingUsernameExpiration = ConstU32<{ 7 * DAYS }>;
+	type UsernameGracePeriod = ConstU32<{ 3 * DAYS }>;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = weights::pallet_identity::WeightInfo<Runtime>;

cumulus/parachains/runtimes/people/people-westend/src/weights/pallet_identity.rs

@@ -340,7 +340,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	/// Proof: `Identity::AccountOfUsername` (`max_values`: None, `max_size`: Some(73), added: 2548, mode: `MaxEncodedLen`)
 	/// Storage: `Identity::IdentityOf` (r:1 w:1)
 	/// Proof: `Identity::IdentityOf` (`max_values`: None, `max_size`: Some(7572), added: 10047, mode: `MaxEncodedLen`)
-	fn set_username_for() -> Weight {
+	fn set_username_for(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `80`
 		//  Estimated: `11037`
@@ -368,7 +368,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	}
 	/// Storage: `Identity::PendingUsernames` (r:1 w:1)
 	/// Proof: `Identity::PendingUsernames` (`max_values`: None, `max_size`: Some(77), added: 2552, mode: `MaxEncodedLen`)
-	fn remove_expired_approval() -> Weight {
+	fn remove_expired_approval(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `106`
 		//  Estimated: `3542`
@@ -406,4 +406,13 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	fn unbind_username() -> Weight {
+		Weight::zero()
+	}
+	fn remove_username() -> Weight {
+		Weight::zero()
+	}
+	fn kill_username(_p: u32, ) -> Weight {
+		Weight::zero()
+	}
 }

polkadot/runtime/common/src/integration_tests.rs

@@ -279,6 +279,7 @@ impl pallet_identity::Config for Test {
 	type Slashed = ();
 	type BasicDeposit = ConstU32<100>;
 	type ByteDeposit = ConstU32<10>;
+	type UsernameDeposit = ConstU32<10>;
 	type SubAccountDeposit = ConstU32<100>;
 	type MaxSubAccounts = ConstU32<2>;
 	type IdentityInformation = IdentityInfo<ConstU32<2>>;
@@ -289,6 +290,7 @@ impl pallet_identity::Config for Test {
 	type SigningPublicKey = <MultiSignature as Verify>::Signer;
 	type UsernameAuthorityOrigin = EnsureRoot<AccountId>;
 	type PendingUsernameExpiration = ConstU32<100>;
+	type UsernameGracePeriod = ConstU32<10>;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = ();

polkadot/runtime/rococo/src/lib.rs

@@ -685,6 +685,7 @@ parameter_types! {
 	// Minimum 100 bytes/ROC deposited (1 CENT/byte)
 	pub const BasicDeposit: Balance = 1000 * CENTS;       // 258 bytes on-chain
 	pub const ByteDeposit: Balance = deposit(0, 1);
+	pub const UsernameDeposit: Balance = deposit(0, 32);
 	pub const SubAccountDeposit: Balance = 200 * CENTS;   // 53 bytes on-chain
 	pub const MaxSubAccounts: u32 = 100;
 	pub const MaxAdditionalFields: u32 = 100;
@@ -696,6 +697,7 @@ impl pallet_identity::Config for Runtime {
 	type Currency = Balances;
 	type BasicDeposit = BasicDeposit;
 	type ByteDeposit = ByteDeposit;
+	type UsernameDeposit = UsernameDeposit;
 	type SubAccountDeposit = SubAccountDeposit;
 	type MaxSubAccounts = MaxSubAccounts;
 	type IdentityInformation = IdentityInfo<MaxAdditionalFields>;
@@ -707,6 +709,7 @@ impl pallet_identity::Config for Runtime {
 	type SigningPublicKey = <Signature as Verify>::Signer;
 	type UsernameAuthorityOrigin = EnsureRoot<Self::AccountId>;
 	type PendingUsernameExpiration = ConstU32<{ 7 * DAYS }>;
+	type UsernameGracePeriod = ConstU32<{ 30 * DAYS }>;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = weights::pallet_identity::WeightInfo<Runtime>;

polkadot/runtime/rococo/src/weights/pallet_identity.rs

@@ -362,7 +362,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	/// Proof: `Identity::AccountOfUsername` (`max_values`: None, `max_size`: Some(73), added: 2548, mode: `MaxEncodedLen`)
 	/// Storage: `Identity::IdentityOf` (r:1 w:1)
 	/// Proof: `Identity::IdentityOf` (`max_values`: None, `max_size`: Some(7572), added: 10047, mode: `MaxEncodedLen`)
-	fn set_username_for() -> Weight {
+	fn set_username_for(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `80`
 		//  Estimated: `11037`
@@ -390,7 +390,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	}
 	/// Storage: `Identity::PendingUsernames` (r:1 w:1)
 	/// Proof: `Identity::PendingUsernames` (`max_values`: None, `max_size`: Some(77), added: 2552, mode: `MaxEncodedLen`)
-	fn remove_expired_approval() -> Weight {
+	fn remove_expired_approval(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `106`
 		//  Estimated: `3542`
@@ -428,4 +428,13 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	fn unbind_username() -> Weight {
+		Weight::zero()
+	}
+	fn remove_username() -> Weight {
+		Weight::zero()
+	}
+	fn kill_username(_p: u32, ) -> Weight {
+		Weight::zero()
+	}
 }

polkadot/runtime/westend/src/lib.rs

@@ -928,6 +928,7 @@ parameter_types! {
 	// Minimum 100 bytes/KSM deposited (1 CENT/byte)
 	pub const BasicDeposit: Balance = 1000 * CENTS;       // 258 bytes on-chain
 	pub const ByteDeposit: Balance = deposit(0, 1);
+	pub const UsernameDeposit: Balance = deposit(0, 32);
 	pub const SubAccountDeposit: Balance = 200 * CENTS;   // 53 bytes on-chain
 	pub const MaxSubAccounts: u32 = 100;
 	pub const MaxAdditionalFields: u32 = 100;
@@ -940,6 +941,7 @@ impl pallet_identity::Config for Runtime {
 	type Slashed = ();
 	type BasicDeposit = BasicDeposit;
 	type ByteDeposit = ByteDeposit;
+	type UsernameDeposit = UsernameDeposit;
 	type SubAccountDeposit = SubAccountDeposit;
 	type MaxSubAccounts = MaxSubAccounts;
 	type IdentityInformation = IdentityInfo<MaxAdditionalFields>;
@@ -950,6 +952,7 @@ impl pallet_identity::Config for Runtime {
 	type SigningPublicKey = <Signature as Verify>::Signer;
 	type UsernameAuthorityOrigin = EnsureRoot<Self::AccountId>;
 	type PendingUsernameExpiration = ConstU32<{ 7 * DAYS }>;
+	type UsernameGracePeriod = ConstU32<{ 30 * DAYS }>;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = weights::pallet_identity::WeightInfo<Runtime>;

polkadot/runtime/westend/src/weights/pallet_identity.rs

@@ -366,7 +366,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	/// Proof: `Identity::AccountOfUsername` (`max_values`: None, `max_size`: Some(73), added: 2548, mode: `MaxEncodedLen`)
 	/// Storage: `Identity::IdentityOf` (r:1 w:1)
 	/// Proof: `Identity::IdentityOf` (`max_values`: None, `max_size`: Some(7572), added: 10047, mode: `MaxEncodedLen`)
-	fn set_username_for() -> Weight {
+	fn set_username_for(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `80`
 		//  Estimated: `11037`
@@ -394,7 +394,7 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 	}
 	/// Storage: `Identity::PendingUsernames` (r:1 w:1)
 	/// Proof: `Identity::PendingUsernames` (`max_values`: None, `max_size`: Some(77), added: 2552, mode: `MaxEncodedLen`)
-	fn remove_expired_approval() -> Weight {
+	fn remove_expired_approval(_p: u32, ) -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `106`
 		//  Estimated: `3542`
@@ -432,4 +432,13 @@ impl<T: frame_system::Config> pallet_identity::WeightInfo for WeightInfo<T> {
 			.saturating_add(T::DbWeight::get().reads(2))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	fn unbind_username() -> Weight {
+		Weight::zero()
+	}
+	fn remove_username() -> Weight {
+		Weight::zero()
+	}
+	fn kill_username(_p: u32, ) -> Weight {
+		Weight::zero()
+	}
 }

substrate/bin/node/runtime/src/impls.rs

@@ -65,7 +65,7 @@ impl IdentityVerifier<AccountId> for AllianceIdentityVerifier {
 	fn has_good_judgement(who: &AccountId) -> bool {
 		use pallet_identity::{IdentityOf, Judgement};
 		IdentityOf::<Runtime>::get(who)
-			.map(|(registration, _)| registration.judgements)
+			.map(|registration| registration.judgements)
 			.map_or(false, |judgements| {
 				judgements
 					.iter()

substrate/bin/node/runtime/src/lib.rs

@@ -1544,6 +1544,7 @@ parameter_types! {
 	// information, already accounted for by the byte deposit
 	pub const BasicDeposit: Balance = deposit(1, 17);
 	pub const ByteDeposit: Balance = deposit(0, 1);
+	pub const UsernameDeposit: Balance = deposit(0, 32);
 	pub const SubAccountDeposit: Balance = 2 * DOLLARS;   // 53 bytes on-chain
 	pub const MaxSubAccounts: u32 = 100;
 	pub const MaxAdditionalFields: u32 = 100;
@@ -1555,6 +1556,7 @@ impl pallet_identity::Config for Runtime {
 	type Currency = Balances;
 	type BasicDeposit = BasicDeposit;
 	type ByteDeposit = ByteDeposit;
+	type UsernameDeposit = UsernameDeposit;
 	type SubAccountDeposit = SubAccountDeposit;
 	type MaxSubAccounts = MaxSubAccounts;
 	type IdentityInformation = IdentityInfo<MaxAdditionalFields>;
@@ -1566,6 +1568,7 @@ impl pallet_identity::Config for Runtime {
 	type SigningPublicKey = <Signature as traits::Verify>::Signer;
 	type UsernameAuthorityOrigin = EnsureRoot<Self::AccountId>;
 	type PendingUsernameExpiration = ConstU32<{ 7 * DAYS }>;
+	type UsernameGracePeriod = ConstU32<{ 30 * DAYS }>;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = pallet_identity::weights::SubstrateWeight<Runtime>;

substrate/frame/alliance/src/mock.rs

@@ -85,11 +85,13 @@ impl pallet_collective::Config<AllianceCollective> for Test {
 parameter_types! {
 	pub const BasicDeposit: u64 = 100;
 	pub const ByteDeposit: u64 = 10;
+	pub const UsernameDeposit: u64 = 10;
 	pub const SubAccountDeposit: u64 = 100;
 	pub const MaxSubAccounts: u32 = 2;
 	pub const MaxAdditionalFields: u32 = 2;
 	pub const MaxRegistrars: u32 = 20;
 	pub const PendingUsernameExpiration: u64 = 100;
+	pub const UsernameGracePeriod: u64 = 10;
 }
 ord_parameter_types! {
 	pub const One: u64 = 1;
@@ -106,6 +108,7 @@ impl pallet_identity::Config for Test {
 	type Currency = Balances;
 	type BasicDeposit = BasicDeposit;
 	type ByteDeposit = ByteDeposit;
+	type UsernameDeposit = UsernameDeposit;
 	type SubAccountDeposit = SubAccountDeposit;
 	type MaxSubAccounts = MaxSubAccounts;
 	type IdentityInformation = IdentityInfo<MaxAdditionalFields>;
@@ -117,6 +120,7 @@ impl pallet_identity::Config for Test {
 	type SigningPublicKey = AccountU64;
 	type UsernameAuthorityOrigin = EnsureOneOrRoot;
 	type PendingUsernameExpiration = PendingUsernameExpiration;
+	type UsernameGracePeriod = UsernameGracePeriod;
 	type MaxSuffixLength = ConstU32<7>;
 	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = ();
@@ -149,7 +153,7 @@ impl IdentityVerifier<AccountId> for AllianceIdentityVerifier {
 
 	fn has_good_judgement(who: &AccountId) -> bool {
 		if let Some(judgements) =
-			IdentityOf::<Test>::get(who).map(|(registration, _)| registration.judgements)
+			IdentityOf::<Test>::get(who).map(|registration| registration.judgements)
 		{
 			judgements
 				.iter()

substrate/frame/identity/README.md

@@ -27,15 +27,24 @@ no state-bloat attack is viable.
 
 #### Usernames
 
-The pallet provides functionality for username authorities to issue usernames. When an account
-receives a username, they get a default instance of `IdentityInfo`. Usernames also serve as a
-reverse lookup from username to account.
+The pallet provides functionality for username authorities to issue usernames, which are independent
+of the identity information functionality; an account can set:
+- an identity without setting a username
+- a username without setting an identity
+- an identity and a username
 
-Username authorities are given an allocation by governance to prevent state bloat. Usernames
-impose no cost or deposit on the user.
+The username functionality implemented in this pallet is meant to be a user friendly lookup of
+accounts. There are mappings in both directions, "account -> username" and "username -> account".
 
-Users can have multiple usernames that map to the same `AccountId`, however one `AccountId` can
-only map to a single username, known as the *primary*.
+To grant a username, a username authority can either:
+- be given an allocation by governane of a specific amount of usernames to issue for free,
+  without any deposit associated with storage costs;
+- put up a deposit for each username it issues (usually a subsidized, reduced deposit, relative
+  to other deposits in the system).
+
+Users can have multiple usernames that map to the same `AccountId`, however one `AccountId` can only
+map to a single username, known as the _primary_. This primary username will be the result of a
+lookup in the `UsernameOf` map for any given account.
 
 ### Interface
 
@@ -50,7 +59,8 @@ only map to a single username, known as the *primary*.
 - `accept_username` - Accept a username issued by a username authority.
 - `remove_expired_approval` - Remove a username that was issued but never accepted.
 - `set_primary_username` - Set a given username as an account's primary.
-- `remove_dangling_username` - Remove a username that maps to an account without an identity.
+- `remove_dangling_username` - Remove a username that maps to an account without a primary username.
+- `remove_username` - Remove a username after its grace period has ended.
 
 ##### For General Users with Sub-Identities
 - `set_subs` - Set the sub-accounts of an identity.
@@ -66,12 +76,14 @@ only map to a single username, known as the *primary*.
 
 ##### For Username Authorities
 - `set_username_for` - Set a username for a given account. The account must approve it.
+- `unbind_username` - Start the grace period for a username.
 
 ##### For Superusers
 - `add_registrar` - Add a new registrar to the system.
 - `kill_identity` - Forcibly remove the associated identity; the deposit is lost.
 - `add_username_authority` - Add an account with the ability to issue usernames.
 - `remove_username_authority` - Remove an account with the ability to issue usernames.
+- `kill_username` - Forcibly remove a username.
 
 [`Call`]: ./enum.Call.html
 [`Config`]: ./trait.Config.html