fix: buy debt and role addition

contracts/VaultV3.vy

@@ -570,7 +570,7 @@ def _deposit(sender: address, recipient: address, assets: uint256) -> uint256:
     """
     assert self.shutdown == False # dev: shutdown
     assert recipient not in [self, empty(address)], "invalid recipient"
-    assert self._total_assets() + assets <= self.deposit_limit, "exceed deposit limit"
+    assert self._total_assets() + assets <= self.deposit_limit, "ERC4626: deposit more than max"
 
     # Transfer the tokens to the vault first.
     self._erc20_safe_transfer_from(ASSET.address, msg.sender, self, assets)
@@ -580,7 +580,7 @@ def _deposit(sender: address, recipient: address, assets: uint256) -> uint256:
     # Issue the corresponding shares for assets.
     shares: uint256 = self._issue_shares_for_amount(assets, recipient)
 
-    assert shares > 0, "cannot mint zero"
+    assert shares > 0, "ZERO_SHARES"
 
     log Deposit(sender, recipient, assets, shares)
     return shares
@@ -597,8 +597,8 @@ def _mint(sender: address, recipient: address, shares: uint256) -> uint256:
 
     assets: uint256 = self._convert_to_assets(shares, Rounding.ROUND_UP)
 
-    assert assets > 0, "cannot mint zero"
-    assert self._total_assets() + assets <= self.deposit_limit, "exceed deposit limit"
+    assert assets > 0, "ZERO_ASSETS"
+    assert self._total_assets() + assets <= self.deposit_limit, "ERC4626: mint more than max"
 
     # Transfer the tokens to the vault first.
     self._erc20_safe_transfer_from(ASSET.address, msg.sender, self, assets)
@@ -668,7 +668,7 @@ def _redeem(
     shares: uint256 = shares_to_burn
     shares_balance: uint256 = self.balance_of[owner]
 
-    assert shares > 0, "no shares to redeem"
+    assert shares > 0, "ZERO_SHARES"
     assert shares_balance >= shares, "insufficient shares to redeem"
 
     if sender != owner:
@@ -1273,15 +1273,45 @@ def _enforce_role(account: address, role: Roles):
 @external
 def set_role(account: address, role: Roles):
     """
-    @notice Set the role of an account.
+    @notice Set the roles for of an account.
+    @dev This will fully override an accounts current roles
+     so it should include all roles the account should hold.
     @param account The account to set the role for.
-    @param role The role to set.
+    @param role The roles the account should hold.
     """
     assert msg.sender == self.role_manager
     self.roles[account] = role
 
     log RoleSet(account, role)
 
+@external
+def add_role(account: address, role: Roles):
+    """
+    @notice Add a new role to an address.
+    @dev This will add a new role to the account
+     without effecting any of the previously held roles.
+    @param account The account to add a role to.
+    @param role The new role to add to account.
+    """
+    assert msg.sender == self.role_manager
+    self.roles[account] = self.roles[account] | role
+
+    log RoleSet(account, self.roles[account])
+
+@external
+def remove_role(account: address, role: Roles):
+    """
+    @notice Remove a single role from an account.
+    @dev This will leave all other roles for the 
+     account unchanged.
+    @param account The account to remove a Role from.
+    @param role The Role to remove.
+    """
+    assert msg.sender == self.role_manager
+    self.roles[account] = self.roles[account] & ~role
+
+    log RoleSet(account, self.roles[account])
+
 @external
 def set_open_role(role: Roles):
     """
@@ -1390,9 +1420,8 @@ def buy_debt(strategy: address, amount: uint256):
     @dev This should only ever be used in an emergency in place
     of force revoking a strategy in order to not report a loss.
     It allows the DEBT_PURCHASER role to buy the strategies debt
-    for an equal amount of `asset`. It's important to note that 
-    this does rely on the strategies `convertToShares` function to
-    determine the amount of shares to buy.
+    for an equal amount of `asset`. 
+
     @param strategy The strategy to buy the debt for
     @param amount The amount of debt to buy from the vault.
     """
@@ -1401,35 +1430,37 @@ def buy_debt(strategy: address, amount: uint256):
 
     # Cache the current debt.
     current_debt: uint256 = self.strategies[strategy].current_debt
-
+    _amount: uint256 = amount
+
     assert current_debt > 0, "nothing to buy"
-    assert amount > 0, "nothing to buy with"
+    assert _amount > 0, "nothing to buy with"
+
+    if _amount > current_debt:
+        _amount = current_debt
 
-    # Get the current shares value for the amount.
-    shares: uint256 = IStrategy(strategy).convertToShares(amount)
+    # We get the proportion of the debt that is being bought and
+    # transfer the equivalant shares. We assume this is being used
+    # due to strategy issues so won't rely on its conversion rates.
+    shares: uint256 = IStrategy(strategy).balanceOf(self) * _amount / current_debt
 
     assert shares > 0, "can't buy 0"
-    assert shares <= IStrategy(strategy).balanceOf(self), "not enough shares"
-
-    self._erc20_safe_transfer_from(ASSET.address, msg.sender, self, amount)
 
-    # Adjust if needed to not underflow on math
-    bought: uint256 = min(current_debt, amount)
+    self._erc20_safe_transfer_from(ASSET.address, msg.sender, self, _amount)
 
     # Lower strategy debt
-    self.strategies[strategy].current_debt -= bought
+    self.strategies[strategy].current_debt -= _amount
     # lower total debt
-    self.total_debt -= bought
+    self.total_debt -= _amount
     # Increase total idle
-    self.total_idle += bought
+    self.total_idle += _amount
 
     # log debt change
-    log DebtUpdated(strategy, current_debt, current_debt - bought)
+    log DebtUpdated(strategy, current_debt, current_debt - _amount)
 
     # Transfer the strategies shares out.
     self._erc20_safe_transfer(strategy, msg.sender, shares)
 
-    log DebtPurchased(strategy, bought)
+    log DebtPurchased(strategy, _amount)
 
 ## STRATEGY MANAGEMENT ##
 @external

tests/e2e/test_deposit_withdraw_flow.py

@@ -20,7 +20,7 @@ def test_deposit_and_withdraw(asset, gov, fish, fish_amount, create_vault):
     # set deposit limit to half_amount and max deposit to test deposit limit
     vault.set_deposit_limit(half_amount, sender=gov)
 
-    with ape.reverts("exceed deposit limit"):
+    with ape.reverts("ERC4626: deposit more than max"):
         vault.deposit(amount, fish.address, sender=fish)
 
     vault.deposit(quarter_amount, fish.address, sender=fish)

tests/unit/vault/test_buy_debt.py

@@ -75,7 +75,7 @@ def test_buy_debt__no_amount__reverts(
         vault.buy_debt(strategy, 0, sender=gov)
 
 
-def test_buy_debt__to_many_shares__reverts(
+def test_buy_debt__more_than_available__withdraws_current_debt(
     gov,
     asset,
     vault,
@@ -94,8 +94,30 @@ def test_buy_debt__to_many_shares__reverts(
     asset.mint(gov.address, amount, sender=gov)
     asset.approve(vault.address, amount, sender=gov)
 
-    with ape.reverts("not enough shares"):
-        vault.buy_debt(strategy, amount * 2, sender=gov)
+    before_balance = asset.balanceOf(gov)
+    before_shares = strategy.balanceOf(gov)
+
+    tx = vault.buy_debt(strategy, amount * 2, sender=gov)
+
+    logs = list(tx.decode_logs(vault.DebtPurchased))[0]
+
+    assert logs.strategy == strategy.address
+    assert logs.amount == amount
+
+    logs = list(tx.decode_logs(vault.DebtUpdated))
+
+    assert len(logs) == 1
+    assert logs[0].strategy == strategy.address
+    assert logs[0].current_debt == amount
+    assert logs[0].new_debt == 0
+
+    assert vault.totalIdle() == amount
+    assert vault.totalDebt() == 0
+    assert vault.pricePerShare() == 10 ** asset.decimals()
+    assert vault.strategies(strategy)["current_debt"] == 0
+    # assert shares got moved
+    assert asset.balanceOf(gov) == before_balance - amount
+    assert strategy.balanceOf(gov) == before_shares + amount
 
 
 def test_buy_debt__full_debt(
@@ -120,7 +142,19 @@ def test_buy_debt__full_debt(
     before_balance = asset.balanceOf(gov)
     before_shares = strategy.balanceOf(gov)
 
-    vault.buy_debt(strategy, amount, sender=gov)
+    tx = vault.buy_debt(strategy, amount, sender=gov)
+
+    logs = list(tx.decode_logs(vault.DebtPurchased))[0]
+
+    assert logs.strategy == strategy.address
+    assert logs.amount == amount
+
+    logs = list(tx.decode_logs(vault.DebtUpdated))
+
+    assert len(logs) == 1
+    assert logs[0].strategy == strategy.address
+    assert logs[0].current_debt == amount
+    assert logs[0].new_debt == 0
 
     assert vault.totalIdle() == amount
     assert vault.totalDebt() == 0
@@ -155,7 +189,19 @@ def test_buy_debt__half_debt(
     before_balance = asset.balanceOf(gov)
     before_shares = strategy.balanceOf(gov)
 
-    vault.buy_debt(strategy, to_buy, sender=gov)
+    tx = vault.buy_debt(strategy, to_buy, sender=gov)
+
+    logs = list(tx.decode_logs(vault.DebtPurchased))[0]
+
+    assert logs.strategy == strategy.address
+    assert logs.amount == to_buy
+
+    logs = list(tx.decode_logs(vault.DebtUpdated))
+
+    assert len(logs) == 1
+    assert logs[0].strategy == strategy.address
+    assert logs[0].current_debt == amount
+    assert logs[0].new_debt == amount - to_buy
 
     assert vault.totalIdle() == to_buy
     assert vault.totalDebt() == amount - to_buy

tests/unit/vault/test_profit_unlocking.py

@@ -266,7 +266,7 @@ def test_gain_no_fees_with_refunds_no_buffer(
     assert asset.balanceOf(fish) == fish_amount + first_profit + total_refunds
 
     # Accountant redeems shares
-    with reverts("no shares to redeem"):
+    with reverts("ZERO_SHARES"):
         vault.redeem(
             vault.balanceOf(accountant), accountant, accountant, sender=accountant
         )
@@ -421,7 +421,7 @@ def test_gain_no_fees_with_refunds_with_buffer(
     )
 
     # Accountant redeems shares
-    with reverts("no shares to redeem"):
+    with reverts("ZERO_SHARES"):
         vault.redeem(
             vault.balanceOf(accountant), accountant, accountant, sender=accountant
         )
@@ -1629,7 +1629,7 @@ def test_loss_no_fees_with_refunds_with_buffer(
     )
 
     # Accountant redeems shares
-    with reverts("no shares to redeem"):
+    with reverts("ZERO_SHARES"):
         vault.redeem(
             vault.balanceOf(accountant), accountant, accountant, sender=accountant
         )