L04 Fix

contracts/src/access/ownable/mod.rs

@@ -68,10 +68,13 @@ pub trait OwnableImpl: Storage<Data> + Internal {
     }
 
     #[modifiers(only_owner)]
-    fn transfer_ownership(&mut self, new_owner: AccountId) -> Result<(), OwnableError> {
+    fn transfer_ownership(&mut self, new_owner: Option<AccountId>) -> Result<(), OwnableError> {
         let old_owner = self.data().owner.get_or_default();
-        self.data().owner.set(&Some(new_owner));
-        self._emit_ownership_transferred_event(old_owner, Some(new_owner));
+        if new_owner == None {
+            return Err(OwnableError::NewOwnerIsNotSet)
+        }
+        self.data().owner.set(&new_owner);
+        self._emit_ownership_transferred_event(old_owner, new_owner);
         Ok(())
     }
 }

contracts/src/governance/timelock_controller/mod.rs

@@ -71,8 +71,8 @@ pub struct Data {
 }
 
 /// Modifier to make a function callable only by a certain role. In
-/// addition to checking the sender's role, None account's role is also
-/// considered. Granting a role to None account is equivalent to enabling
+/// addition to checking the sender's role, if account is set to None, then role is also
+/// considered. Granting a role to None is equivalent to enabling
 /// this role for everyone.
 #[modifier_definition]
 pub fn only_role_or_open_role<T, F, R, E>(instance: &mut T, body: F, role: RoleType) -> Result<R, E>

contracts/src/traits/ownable/mod.rs

@@ -59,5 +59,5 @@ pub trait Ownable {
     ///
     /// Panics with `NewOwnerIsZero` error if new owner's address is zero.
     #[ink(message)]
-    fn transfer_ownership(&mut self, new_owner: AccountId) -> Result<(), OwnableError>;
+    fn transfer_ownership(&mut self, new_owner: Option<AccountId>) -> Result<(), OwnableError>;
 }

lang/codegen/src/implementations.rs

@@ -1732,7 +1732,7 @@ pub(crate) fn impl_ownable(impl_args: &mut ImplArgs) {
             }
 
             #[ink(message)]
-            fn transfer_ownership(&mut self, new_owner: AccountId) -> Result<(), OwnableError> {
+            fn transfer_ownership(&mut self, new_owner: Option<AccountId>) -> Result<(), OwnableError> {
                 OwnableImpl::transfer_ownership(self, new_owner)
             }
         }