Adding the ability to moving a portion of a stake from one subnet to another

pallets/subtensor/src/macros/dispatches.rs

@@ -1053,8 +1053,9 @@ mod dispatches {
             destination_hotkey: T::AccountId,
             origin_netuid: u16,
             destination_netuid: u16,
+            amount_moved: Option<u64>,
         ) -> DispatchResult {
-            Self::do_move_stake(origin, origin_hotkey, destination_hotkey, origin_netuid, destination_netuid)
+            Self::do_move_stake(origin, origin_hotkey, destination_hotkey, origin_netuid, destination_netuid, amount_moved)
         }
     }
 }

pallets/subtensor/src/staking/move_stake.rs

@@ -30,6 +30,7 @@ impl<T: Config> Pallet<T> {
         destination_hotkey: T::AccountId,
         origin_netuid: u16,
         destination_netuid: u16,
+        amount_moved: Option<u64>,
     ) -> dispatch::DispatchResult {
         // --- 1. Check that the origin is signed by the origin_hotkey.
         let coldkey = ensure_signed(origin)?;
@@ -66,14 +67,20 @@ impl<T: Config> Pallet<T> {
         }
 
         // --- 6. Get the current alpha stake for the origin hotkey-coldkey pair in the origin subnet
+        // or use amount_moved
         let origin_alpha = Alpha::<T>::get((origin_hotkey.clone(), coldkey.clone(), origin_netuid));
 
+        let move_alpha = match amount_moved {
+            Some(amount) if amount <= origin_alpha => amount,
+            _ => origin_alpha,
+        };
+
         // --- 7. Unstake the full amount of alpha from the origin subnet, converting it to TAO
         let origin_tao = Self::unstake_from_subnet(
             &origin_hotkey.clone(),
             &coldkey.clone(),
             origin_netuid,
-            origin_alpha,
+            move_alpha,
         );
 
         // --- 8. Stake the resulting TAO into the destination subnet for the destination hotkey