Use free balance rather than total balance for elections phragmen (pa…

…ritytech#10646)

* use free balance rather than total balance

* Docs

Co-authored-by: emostov <32168567+emostov@users.noreply.github.com>

frame/elections-phragmen/src/lib.rs

@@ -280,7 +280,7 @@ pub mod pallet {
  /// - be less than the number of possible candidates. Note that all current members and
  /// runners-up are also automatically candidates for the next round.
  ///
- /// If `value` is more than `who`'s total balance, then the maximum of the two is used.
+ /// If `value` is more than `who`'s free balance, then the maximum of the two is used.
  ///
  /// The dispatch origin of this call must be signed.
  ///
@@ -342,7 +342,7 @@ pub mod pallet {
  };
 
  // Amount to be locked up.
- let locked_stake = value.min(T::Currency::total_balance(&who));
+ let locked_stake = value.min(T::Currency::free_balance(&who));
  T::Currency::set_lock(T::PalletId::get(), &who, locked_stake, WithdrawReasons::all());
 
  Voting::<T>::insert(&who, Voter { votes, deposit: new_deposit, stake: locked_stake });
@@ -1667,11 +1667,13 @@ mod tests {
  System::set_block_number(5);
  Elections::on_initialize(System::block_number());
 
+ assert_eq!(balances(&4), (34, 6));
+ assert_eq!(balances(&5), (45, 5));
  assert_eq!(
  Elections::members(),
  vec![
- SeatHolder { who: 4, stake: 40, deposit: 4 },
- SeatHolder { who: 5, stake: 50, deposit: 3 },
+ SeatHolder { who: 4, stake: 34, deposit: 4 },
+ SeatHolder { who: 5, stake: 45, deposit: 3 },
  ]
  );
  })
@@ -1762,7 +1764,7 @@ mod tests {
  assert_ok!(vote(Origin::signed(2), vec![5], 20));
 
  assert_eq!(balances(&2), (18, 2));
- assert_eq!(has_lock(&2), 20);
+ assert_eq!(has_lock(&2), 18);
  });
  }
 
@@ -1789,9 +1791,10 @@ mod tests {
  assert_ok!(submit_candidacy(Origin::signed(4)));
  assert_ok!(vote(Origin::signed(2), vec![5], 20));
 
+ // User only locks up to their free balance.
  assert_eq!(balances(&2), (18, 2));
- assert_eq!(has_lock(&2), 20);
- assert_eq!(locked_stake_of(&2), 20);
+ assert_eq!(has_lock(&2), 18);
+ assert_eq!(locked_stake_of(&2), 18);
 
  // can update; different stake; different lock and reserve.
  assert_ok!(vote(Origin::signed(2), vec![5, 4], 15));
@@ -1856,8 +1859,8 @@ mod tests {
  // 2 + 2
  assert_eq!(balances(&2), (16, 4));
  assert_eq!(Elections::voting(&2).deposit, 4);
- assert_eq!(has_lock(&2), 18);
- assert_eq!(locked_stake_of(&2), 18);
+ assert_eq!(has_lock(&2), 16);
+ assert_eq!(locked_stake_of(&2), 16);
 
  // back to 1 vote.
  assert_ok!(vote(Origin::signed(2), vec![4], 12));
@@ -2031,15 +2034,18 @@ mod tests {
  }
 
  #[test]
- fn can_vote_for_more_than_total_balance_but_moot() {
+ fn can_vote_for_more_than_free_balance_but_moot() {
  ExtBuilder::default().build_and_execute(|| {
  assert_ok!(submit_candidacy(Origin::signed(5)));
  assert_ok!(submit_candidacy(Origin::signed(4)));
 
- assert_ok!(vote(Origin::signed(2), vec![4, 5], 30));
- // you can lie but won't get away with it.
- assert_eq!(locked_stake_of(&2), 20);
- assert_eq!(has_lock(&2), 20);
+ // User has 100 free and 50 reserved.
+ assert_ok!(Balances::set_balance(Origin::root(), 2, 100, 50));
+ // User tries to vote with 150 tokens.
+ assert_ok!(vote(Origin::signed(2), vec![4, 5], 150));
+ // We truncate to only their free balance, after reserving additional for voting.
+ assert_eq!(locked_stake_of(&2), 98);
+ assert_eq!(has_lock(&2), 98);
  });
  }
 
@@ -2052,8 +2058,10 @@ mod tests {
  assert_ok!(vote(Origin::signed(3), vec![5], 30));
 
  assert_eq_uvec!(all_voters(), vec![2, 3]);
- assert_eq!(locked_stake_of(&2), 20);
- assert_eq!(locked_stake_of(&3), 30);
+ assert_eq!(balances(&2), (12, 8));
+ assert_eq!(locked_stake_of(&2), 12);
+ assert_eq!(balances(&3), (22, 8));
+ assert_eq!(locked_stake_of(&3), 22);
  assert_eq!(votes_of(&2), vec![5]);
  assert_eq!(votes_of(&3), vec![5]);
 
@@ -2133,7 +2141,10 @@ mod tests {
  System::set_block_number(5);
  Elections::on_initialize(System::block_number());
 
- assert_eq!(members_and_stake(), vec![(3, 30), (5, 20)]);
+ assert_eq!(balances(&3), (25, 5));
+ // votes for 5
+ assert_eq!(balances(&2), (18, 2));
+ assert_eq!(members_and_stake(), vec![(3, 25), (5, 18)]);
  assert!(Elections::runners_up().is_empty());
 
  assert_eq_uvec!(all_voters(), vec![2, 3, 4]);
@@ -2168,10 +2179,10 @@ mod tests {
  Elections::on_initialize(System::block_number());
 
  System::assert_last_event(Event::Elections(super::Event::NewTerm {
- new_members: vec![(4, 40), (5, 50)],
+ new_members: vec![(4, 35), (5, 45)],
  }));
 
- assert_eq!(members_and_stake(), vec![(4, 40), (5, 50)]);
+ assert_eq!(members_and_stake(), vec![(4, 35), (5, 45)]);
  assert_eq!(runners_up_and_stake(), vec![]);
 
  assert_ok!(Elections::remove_voter(Origin::signed(5)));
@@ -2202,7 +2213,7 @@ mod tests {
  System::set_block_number(5);
  Elections::on_initialize(System::block_number());
 
- assert_eq!(members_and_stake(), vec![(5, 50)]);
+ assert_eq!(members_and_stake(), vec![(5, 45)]);
  assert_eq!(Elections::election_rounds(), 1);
 
  // but now it has a valid target.
@@ -2212,7 +2223,7 @@ mod tests {
  Elections::on_initialize(System::block_number());
 
  // candidate 4 is affected by an old vote.
- assert_eq!(members_and_stake(), vec![(4, 30), (5, 50)]);
+ assert_eq!(members_and_stake(), vec![(4, 28), (5, 45)]);
  assert_eq!(Elections::election_rounds(), 2);
  assert_eq_uvec!(all_voters(), vec![3, 5]);
  });
@@ -2300,16 +2311,16 @@ mod tests {
 
  System::set_block_number(5);
  Elections::on_initialize(System::block_number());
- assert_eq!(members_and_stake(), vec![(4, 40), (5, 50)]);
- assert_eq!(runners_up_and_stake(), vec![(2, 20), (3, 30)]);
+ assert_eq!(members_and_stake(), vec![(4, 35), (5, 45)]);
+ assert_eq!(runners_up_and_stake(), vec![(2, 15), (3, 25)]);
 
- assert_ok!(vote(Origin::signed(5), vec![5], 15));
+ assert_ok!(vote(Origin::signed(5), vec![5], 10));
 
  System::set_block_number(10);
  Elections::on_initialize(System::block_number());
 
- assert_eq!(members_and_stake(), vec![(3, 30), (4, 40)]);
- assert_eq!(runners_up_and_stake(), vec![(5, 15), (2, 20)]);
+ assert_eq!(members_and_stake(), vec![(3, 25), (4, 35)]);
+ assert_eq!(runners_up_and_stake(), vec![(5, 10), (2, 15)]);
  });
  }
 
@@ -2443,8 +2454,8 @@ mod tests {
  System::set_block_number(b.into());
  Elections::on_initialize(System::block_number());
  // we keep re-electing the same folks.
- assert_eq!(members_and_stake(), vec![(4, 40), (5, 50)]);
- assert_eq!(runners_up_and_stake(), vec![(2, 20), (3, 30)]);
+ assert_eq!(members_and_stake(), vec![(4, 35), (5, 45)]);
+ assert_eq!(runners_up_and_stake(), vec![(2, 15), (3, 25)]);
  // no new candidates but old members and runners-up are always added.
  assert!(candidate_ids().is_empty());
  assert_eq!(Elections::election_rounds(), b / 5);
@@ -2596,7 +2607,7 @@ mod tests {
  Elections::on_initialize(System::block_number());
 
  // 3, 4 are new members, must still be bonded, nothing slashed.
- assert_eq!(members_and_stake(), vec![(3, 30), (4, 48)]);
+ assert_eq!(members_and_stake(), vec![(3, 25), (4, 43)]);
  assert_eq!(balances(&3), (25, 5));
  assert_eq!(balances(&4), (35, 5));
 
@@ -2607,7 +2618,7 @@ mod tests {
  assert_eq!(balances(&5), (45, 2));
 
  System::assert_has_event(Event::Elections(super::Event::NewTerm {
- new_members: vec![(4, 40), (5, 50)],
+ new_members: vec![(4, 35), (5, 45)],
  }));
  })
  }
@@ -2646,9 +2657,9 @@ mod tests {
  System::set_block_number(5);
  Elections::on_initialize(System::block_number());
  // id: low -> high.
- assert_eq!(members_and_stake(), vec![(4, 50), (5, 40)]);
+ assert_eq!(members_and_stake(), vec![(4, 45), (5, 35)]);
  // merit: low -> high.
- assert_eq!(runners_up_and_stake(), vec![(3, 20), (2, 30)]);
+ assert_eq!(runners_up_and_stake(), vec![(3, 15), (2, 25)]);
  });
  }