diff --git a/srml/balances/src/lib.rs b/srml/balances/src/lib.rs index 71f37cb8f8193..e22dba3fee477 100644 --- a/srml/balances/src/lib.rs +++ b/srml/balances/src/lib.rs @@ -397,6 +397,8 @@ decl_module! { /// `T::OnNewAccount::on_new_account` to be called. /// - Removing enough funds from an account will trigger /// `T::DustRemoval::on_unbalanced` and `T::OnFreeBalanceZero::on_free_balance_zero`. + /// - `transfer_keep_alive` works the same way as `transfer`, but has an additional + /// check that the transfer will not kill the origin account. /// /// # #[weight = SimpleDispatchInfo::FixedNormal(1_000_000)] @@ -407,7 +409,7 @@ decl_module! { ) { let transactor = ensure_signed(origin)?; let dest = T::Lookup::lookup(dest)?; - >::transfer(&transactor, &dest, value)?; + >::transfer(&transactor, &dest, value, ExistenceRequirement::AllowDeath)?; } /// Set the balances of a given account. @@ -462,8 +464,26 @@ decl_module! { ensure_root(origin)?; let source = T::Lookup::lookup(source)?; let dest = T::Lookup::lookup(dest)?; - >::transfer(&source, &dest, value)?; + >::transfer(&source, &dest, value, ExistenceRequirement::AllowDeath)?; } + + /// Same as the [`transfer`] call, but with a check that the transfer will not kill the + /// origin account. + /// + /// 99% of the time you want [`transfer`] instead. + /// + /// [`transfer`]: struct.Module.html#method.transfer + #[weight = SimpleDispatchInfo::FixedNormal(1_000_000)] + pub fn transfer_keep_alive( + origin, + dest: ::Source, + #[compact] value: T::Balance + ) { + let transactor = ensure_signed(origin)?; + let dest = T::Lookup::lookup(dest)?; + >::transfer(&transactor, &dest, value, ExistenceRequirement::KeepAlive)?; + } + } } @@ -851,7 +871,12 @@ where } } - fn transfer(transactor: &T::AccountId, dest: &T::AccountId, value: Self::Balance) -> Result { + fn transfer( + transactor: &T::AccountId, + dest: &T::AccountId, + value: Self::Balance, + existence_requirement: ExistenceRequirement, + ) -> Result { let from_balance = Self::free_balance(transactor); let to_balance = Self::free_balance(dest); let would_create = to_balance.is_zero(); @@ -878,6 +903,12 @@ where }; if transactor != dest { + if existence_requirement == ExistenceRequirement::KeepAlive { + if new_from_balance < Self::minimum_balance() { + return Err("transfer would kill account"); + } + } + Self::set_free_balance(transactor, new_from_balance); if !>::exists(dest) { Self::new_account(dest, new_to_balance); diff --git a/srml/balances/src/tests.rs b/srml/balances/src/tests.rs index 839ac67991c83..8afec6f697de1 100644 --- a/srml/balances/src/tests.rs +++ b/srml/balances/src/tests.rs @@ -24,7 +24,7 @@ use sr_primitives::traits::SignedExtension; use support::{ assert_noop, assert_ok, assert_err, traits::{LockableCurrency, LockIdentifier, WithdrawReason, WithdrawReasons, - Currency, ReservableCurrency} + Currency, ReservableCurrency, ExistenceRequirement::AllowDeath} }; use transaction_payment::ChargeTransactionPayment; use system::RawOrigin; @@ -39,7 +39,7 @@ fn basic_locking_should_work() { assert_eq!(Balances::free_balance(&1), 10); Balances::set_lock(ID_1, &1, 9, u64::max_value(), WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 5), + >::transfer(&1, &2, 5, AllowDeath), "account liquidity restrictions prevent withdrawal" ); }); @@ -49,7 +49,7 @@ fn basic_locking_should_work() { fn partial_locking_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, 5, u64::max_value(), WithdrawReasons::all()); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); }); } @@ -58,7 +58,7 @@ fn lock_removal_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, u64::max_value(), u64::max_value(), WithdrawReasons::all()); Balances::remove_lock(ID_1, &1); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); }); } @@ -67,7 +67,7 @@ fn lock_replacement_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, u64::max_value(), u64::max_value(), WithdrawReasons::all()); Balances::set_lock(ID_1, &1, 5, u64::max_value(), WithdrawReasons::all()); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); }); } @@ -76,7 +76,7 @@ fn double_locking_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, 5, u64::max_value(), WithdrawReasons::all()); Balances::set_lock(ID_2, &1, 5, u64::max_value(), WithdrawReasons::all()); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); }); } @@ -86,7 +86,7 @@ fn combination_locking_should_work() { Balances::set_lock(ID_1, &1, u64::max_value(), 0, WithdrawReasons::none()); Balances::set_lock(ID_2, &1, 0, u64::max_value(), WithdrawReasons::none()); Balances::set_lock(ID_3, &1, 0, 0, WithdrawReasons::all()); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); }); } @@ -95,17 +95,17 @@ fn lock_value_extension_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, 5, u64::max_value(), WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); Balances::extend_lock(ID_1, &1, 2, u64::max_value(), WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); Balances::extend_lock(ID_1, &1, 8, u64::max_value(), WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 3), + >::transfer(&1, &2, 3, AllowDeath), "account liquidity restrictions prevent withdrawal" ); }); @@ -120,7 +120,7 @@ fn lock_reasons_should_work() { .execute_with(|| { Balances::set_lock(ID_1, &1, 10, u64::max_value(), WithdrawReason::Transfer.into()); assert_noop!( - >::transfer(&1, &2, 1), + >::transfer(&1, &2, 1, AllowDeath), "account liquidity restrictions prevent withdrawal" ); assert_ok!(>::reserve(&1, 1)); @@ -134,7 +134,7 @@ fn lock_reasons_should_work() { ).is_ok()); Balances::set_lock(ID_1, &1, 10, u64::max_value(), WithdrawReason::Reserve.into()); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); assert_noop!( >::reserve(&1, 1), "account liquidity restrictions prevent withdrawal" @@ -148,7 +148,7 @@ fn lock_reasons_should_work() { ).is_ok()); Balances::set_lock(ID_1, &1, 10, u64::max_value(), WithdrawReason::TransactionPayment.into()); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); assert_ok!(>::reserve(&1, 1)); assert!( as SignedExtension>::pre_dispatch( ChargeTransactionPayment::from(1), @@ -165,12 +165,12 @@ fn lock_block_number_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, 10, 2, WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 1), + >::transfer(&1, &2, 1, AllowDeath), "account liquidity restrictions prevent withdrawal" ); System::set_block_number(2); - assert_ok!(>::transfer(&1, &2, 1)); + assert_ok!(>::transfer(&1, &2, 1, AllowDeath)); }); } @@ -179,18 +179,18 @@ fn lock_block_number_extension_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, 10, 2, WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); Balances::extend_lock(ID_1, &1, 10, 1, WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); System::set_block_number(2); Balances::extend_lock(ID_1, &1, 10, 8, WithdrawReasons::all()); assert_noop!( - >::transfer(&1, &2, 3), + >::transfer(&1, &2, 3, AllowDeath), "account liquidity restrictions prevent withdrawal" ); }); @@ -201,17 +201,17 @@ fn lock_reasons_extension_should_work() { ExtBuilder::default().existential_deposit(1).monied(true).build().execute_with(|| { Balances::set_lock(ID_1, &1, 10, 10, WithdrawReason::Transfer.into()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); Balances::extend_lock(ID_1, &1, 10, 10, WithdrawReasons::none()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); Balances::extend_lock(ID_1, &1, 10, 10, WithdrawReason::Reserve.into()); assert_noop!( - >::transfer(&1, &2, 6), + >::transfer(&1, &2, 6, AllowDeath), "account liquidity restrictions prevent withdrawal" ); }); @@ -746,3 +746,17 @@ fn burn_must_work() { assert_eq!(Balances::total_issuance(), init_total_issuance); }); } + +#[test] +fn transfer_keep_alive_works() { + ExtBuilder::default().existential_deposit(1).build().execute_with(|| { + let _ = Balances::deposit_creating(&1, 100); + assert_err!( + Balances::transfer_keep_alive(Some(1).into(), 2, 100), + "transfer would kill account" + ); + assert_eq!(Balances::is_dead_account(&1), false); + assert_eq!(Balances::total_balance(&1), 100); + assert_eq!(Balances::total_balance(&2), 0); + }); +} diff --git a/srml/generic-asset/src/lib.rs b/srml/generic-asset/src/lib.rs index 38bff08e12d0b..fda3b6ae048f4 100644 --- a/srml/generic-asset/src/lib.rs +++ b/srml/generic-asset/src/lib.rs @@ -1096,7 +1096,12 @@ where Zero::zero() } - fn transfer(transactor: &T::AccountId, dest: &T::AccountId, value: Self::Balance) -> Result { + fn transfer( + transactor: &T::AccountId, + dest: &T::AccountId, + value: Self::Balance, + _: ExistenceRequirement, // no existential deposit policy for generic asset + ) -> Result { >::make_transfer(&U::asset_id(), transactor, dest, value) } diff --git a/srml/support/src/traits.rs b/srml/support/src/traits.rs index aead54bbca6c5..297e128ebc2f0 100644 --- a/srml/support/src/traits.rs +++ b/srml/support/src/traits.rs @@ -384,6 +384,7 @@ pub trait Currency { source: &AccountId, dest: &AccountId, value: Self::Balance, + existence_requirement: ExistenceRequirement, ) -> result::Result<(), &'static str>; /// Deducts up to `value` from the combined balance of `who`, preferring to deduct from the