Repository: paritytech/substrate
File: frame/elections-phragmen/src/migrations/unlock_and_unreserve_all_funds.rs (Rust)

Code before:
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! A migration that unreserves all deposit and unlocks all stake held in the context of this
//! pallet.

use crate::BalanceOf;
use core::iter::Sum;
use frame_support::traits::{LockableCurrency, OnRuntimeUpgrade, ReservableCurrency};
use sp_core::Get;
use sp_runtime::traits::Zero;
use sp_std::collections::btree_map::BTreeMap;

#[cfg(feature = "try-runtime")]
use sp_std::vec::Vec;

/// A migration that unreserves all deposit and unlocks all stake held in the context of this
/// pallet.
///
/// Useful to prevent funds from being locked up when the pallet is being deprecated.
///
/// The pallet should be made inoperable before or immediately after this migration is run.
///
/// (See also the `RemovePallet` migration in `frame/support/src/migrations.rs`)
pub struct UnlockAndUnreserveAllFunds<T: crate::Config>(sp_std::marker::PhantomData<T>);

impl<T: crate::Config> UnlockAndUnreserveAllFunds<T>
where
	BalanceOf<T>: Sum,
{
	/// Calculates and returns the total amounts deposited and staked by each account in the context
	/// of this pallet.
	///
	/// The deposited and staked amounts are returned in two separate `BTreeMap` collections.
	///
	/// The first `BTreeMap`, `account_deposited_sums`, contains each account's total amount
	/// deposited. This includes deposits made by Members, RunnerUps, Candidates, and Voters.
	///
	/// The second `BTreeMap`, `account_staked_sums`, contains each account's total amount staked.
	/// This includes stakes made by Voters.
	///
	/// # Returns
	///
	/// This function returns a tuple of two `BTreeMap` collections and the weight of the reads:
	///
	/// * `BTreeMap<T::AccountId, BalanceOf<T>>`: Map of account IDs to their respective total
	///   deposit sums.

Review comment (suggestion):
```suggestion
/// The pallet should be made inoperable before this migration is run.
```

Code after:
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! A migration that unreserves all deposit and unlocks all stake held in the context of this
//! pallet.

use crate::BalanceOf;
use core::iter::Sum;
use frame_support::traits::{LockableCurrency, OnRuntimeUpgrade, ReservableCurrency};
use sp_core::Get;
use sp_runtime::traits::Zero;
use sp_std::collections::btree_map::BTreeMap;

#[cfg(feature = "try-runtime")]
use sp_std::vec::Vec;

const LOG_TARGET: &str = "elections_phragmen::migrations::unlock_and_unreserve_all_funds";

/// A migration that unreserves all deposit and unlocks all stake held in the context of this
/// pallet.
///
/// Useful to prevent funds from being locked up when the pallet is being deprecated.
///
/// The pallet should be made inoperable before this migration is run.
///
/// (See also [`RemovePallet`][frame_support::migrations::RemovePallet])
pub struct UnlockAndUnreserveAllFunds<T: crate::Config>(sp_std::marker::PhantomData<T>);

impl<T: crate::Config> UnlockAndUnreserveAllFunds<T> {
	/// Calculates and returns the total amounts deposited and staked by each account in the context
	/// of this pallet.
	///
	/// The deposited and staked amounts are returned in two separate `BTreeMap` collections.
	///
	/// The first `BTreeMap`, `account_deposited_sums`, contains each account's total amount
	/// deposited. This includes deposits made by Members, RunnerUps, Candidates, and Voters.
	///
	/// The second `BTreeMap`, `account_staked_sums`, contains each account's total amount staked.
	/// This includes stakes made by Voters.
	///
	/// # Returns
	///
	/// This function returns a tuple of two `BTreeMap` collections and the weight of the reads:
	///
	/// * `BTreeMap<T::AccountId, BalanceOf<T>>`: Map of account IDs to their respective total
	///   deposit sums.
	/// * `BTreeMap<T::AccountId, BalanceOf<T>>`: Map of account IDs to their respective total