Separate defaults for tx fee from min stake. Make min stake work like ED for stakes.

Author: gztensor

pallets/subtensor/src/lib.rs

@@ -702,11 +702,17 @@ pub mod pallet {
     #[pallet::type_value]
     /// Default minimum stake.
     /// 500k rao matches $0.25 at $500/TAO
-    /// Also used as staking fee
     pub fn DefaultMinStake<T: Config>() -> u64 {
         500_000
     }
 
+    #[pallet::type_value]
+    /// Default staking fee.
+    /// 500k rao matches $0.25 at $500/TAO
+    pub fn DefaultStakingFee<T: Config>() -> u64 {
+        500_000
+    }
+
     #[pallet::type_value]
     /// Default unicode vector for tau symbol.
     pub fn DefaultUnicodeVecU8<T: Config>() -> Vec<u8> {
@@ -1545,13 +1551,15 @@ pub enum CallType {
 pub enum CustomTransactionError {
     ColdkeyInSwapSchedule,
     StakeAmountTooLow,
+    BalanceTooLow,
 }
 
 impl From<CustomTransactionError> for u8 {
     fn from(variant: CustomTransactionError) -> u8 {
         match variant {
             CustomTransactionError::ColdkeyInSwapSchedule => 0,
             CustomTransactionError::StakeAmountTooLow => 1,
+            CustomTransactionError::BalanceTooLow => 2,
         }
     }
 }
@@ -1704,7 +1712,7 @@ where
             Some(Call::add_stake {
                 hotkey: _,
                 netuid: _,
-                amount_staked,
+                amount,
             }) => {
                 // Check that amount parameter is at least the min stake
                 // also check the coldkey balance
@@ -1713,12 +1721,14 @@ where
                 >>::reducible_balance(
                     who, Preservation::Expendable, Fortitude::Polite
                 );
+                let min_amount =
+                    DefaultMinStake::<T>::get().saturating_add(DefaultStakingFee::<T>::get());
 
-                if (*amount_staked < DefaultMinStake::<T>::get())
-                    || (coldkey_balance < DefaultMinStake::<T>::get())
-                {
+                if *amount < min_amount {
                     InvalidTransaction::Custom(CustomTransactionError::StakeAmountTooLow.into())
                         .into()
+                } else if coldkey_balance < min_amount {
+                    InvalidTransaction::Custom(CustomTransactionError::BalanceTooLow.into()).into()
                 } else {
                     Ok(ValidTransaction {
                         priority: Self::get_priority_vanilla(),

pallets/subtensor/src/staking/add_stake.rs

@@ -62,19 +62,17 @@ impl<T: Config> Pallet<T> {
             Error::<T>::HotKeyAccountNotExists
         );
 
-        // Ensure stake_to_be_added is at least DefaultMinStake
-        ensure!(
-            stake_to_be_added >= DefaultMinStake::<T>::get(),
-            Error::<T>::AmountTooLow
-        );
+        // Ensure stake_to_be_added is at least DefaultMinStake plus fee
+        let min_amount = DefaultMinStake::<T>::get().saturating_add(DefaultStakingFee::<T>::get());
+        ensure!(stake_to_be_added >= min_amount, Error::<T>::AmountTooLow);
 
         // 5. Ensure the remove operation from the coldkey is a success.
         let tao_staked: u64 =
             Self::remove_balance_from_coldkey_account(&coldkey, stake_to_be_added)?;
 
         // 6. Swap the stake into alpha on the subnet and increase counters.
         // Emit the staking event.
-        let fee = DefaultMinStake::<T>::get();
+        let fee = DefaultStakingFee::<T>::get();
         Self::stake_into_subnet(&hotkey, &coldkey, netuid, tao_staked, fee);
 
         // Ok and return.

pallets/subtensor/src/staking/move_stake.rs

@@ -68,7 +68,7 @@ impl<T: Config> Pallet<T> {
         );
 
         // --- 7. Unstake the amount of alpha from the origin subnet, converting it to TAO
-        let fee = DefaultMinStake::<T>::get().saturating_div(2); // fee is half of min stake because it is applied twice
+        let fee = DefaultStakingFee::<T>::get().saturating_div(2); // fee is half of min stake because it is applied twice
         let origin_tao = Self::unstake_from_subnet(
             &origin_hotkey.clone(),
             &coldkey.clone(),
@@ -79,7 +79,7 @@ impl<T: Config> Pallet<T> {
 
         // Ensure origin_tao is at least DefaultMinStake
         ensure!(
-            origin_tao >= DefaultMinStake::<T>::get(),
+            origin_tao.saturating_sub(fee) >= DefaultMinStake::<T>::get(),
             Error::<T>::AmountTooLow
         );
 
@@ -181,13 +181,13 @@ impl<T: Config> Pallet<T> {
         );
 
         // 6. Unstake from the origin coldkey; this returns an amount of TAO.
-        let fee = DefaultMinStake::<T>::get().saturating_div(2);
+        let fee = DefaultStakingFee::<T>::get().saturating_div(2);
         let origin_tao =
             Self::unstake_from_subnet(&hotkey, &coldkey, origin_netuid, alpha_amount, fee);
 
         // 7. Ensure the returned TAO meets a minimum stake requirement (if required).
         ensure!(
-            origin_tao >= DefaultMinStake::<T>::get(),
+            origin_tao.saturating_sub(fee) >= DefaultMinStake::<T>::get(),
             Error::<T>::AmountTooLow
         );
 
@@ -288,17 +288,18 @@ impl<T: Config> Pallet<T> {
         );
 
         // 6. Unstake from the origin subnet, returning TAO (or a 1:1 equivalent).
+        let fee = DefaultStakingFee::<T>::get().saturating_div(2);
         let tao_unstaked =
-            Self::unstake_from_subnet(&hotkey, &coldkey, origin_netuid, alpha_amount);
+            Self::unstake_from_subnet(&hotkey, &coldkey, origin_netuid, alpha_amount, fee);
 
         // 7. Check that the unstaked amount is above the minimum stake threshold.
         ensure!(
-            tao_unstaked >= DefaultMinStake::<T>::get(),
+            tao_unstaked.saturating_sub(fee) >= DefaultMinStake::<T>::get(),
             Error::<T>::AmountTooLow
         );
 
         // 8. Stake the unstaked amount into the destination subnet, using the same coldkey/hotkey.
-        Self::stake_into_subnet(&hotkey, &coldkey, destination_netuid, tao_unstaked);
+        Self::stake_into_subnet(&hotkey, &coldkey, destination_netuid, tao_unstaked, fee);
 
         // 9. Emit an event for logging.
         log::info!(

pallets/subtensor/src/staking/remove_stake.rs

@@ -66,7 +66,7 @@ impl<T: Config> Pallet<T> {
         );
 
         // 6. Swap the alpba to tao and update counters for this subnet.
-        let fee = DefaultMinStake::<T>::get();
+        let fee = DefaultStakingFee::<T>::get();
         let tao_unstaked: u64 =
             Self::unstake_from_subnet(&hotkey, &coldkey, netuid, alpha_unstaked, fee);
 
@@ -117,7 +117,7 @@ impl<T: Config> Pallet<T> {
         origin: T::RuntimeOrigin,
         hotkey: T::AccountId,
     ) -> dispatch::DispatchResult {
-        let fee = DefaultMinStake::<T>::get();
+        let fee = DefaultStakingFee::<T>::get();
 
         // 1. We check the transaction is signed by the caller and retrieve the T::AccountId coldkey information.
         let coldkey = ensure_signed(origin)?;
@@ -185,7 +185,7 @@ impl<T: Config> Pallet<T> {
         origin: T::RuntimeOrigin,
         hotkey: T::AccountId,
     ) -> dispatch::DispatchResult {
-        let fee = DefaultMinStake::<T>::get();
+        let fee = DefaultStakingFee::<T>::get();
 
         // 1. We check the transaction is signed by the caller and retrieve the T::AccountId coldkey information.
         let coldkey = ensure_signed(origin)?;

pallets/subtensor/src/tests/epoch.rs

@@ -1505,7 +1505,7 @@ fn test_set_alpha_disabled() {
             signer.clone(),
             hotkey,
             netuid,
-            DefaultMinStake::<Test>::get()
+            DefaultMinStake::<Test>::get() + DefaultStakingFee::<Test>::get()
         ));
         // Only owner can set alpha values
         assert_ok!(SubtensorModule::register_network(signer.clone(), hotkey));
@@ -2600,7 +2600,7 @@ fn test_get_set_alpha() {
             signer.clone(),
             hotkey,
             netuid,
-            DefaultMinStake::<Test>::get()
+            DefaultMinStake::<Test>::get() + DefaultStakingFee::<Test>::get()
         ));
 
         assert_ok!(SubtensorModule::do_set_alpha_values(