Add migration to fix TI after evm fees divergence

pallets/subtensor/src/macros/hooks.rs

@@ -174,7 +174,9 @@ mod hooks {
                 // Fix RootClaimed overclaim caused by single-subnet hotkey swap bug
                 .saturating_add(migrations::migrate_fix_root_claimed_overclaim::migrate_fix_root_claimed_overclaim::<T>())
                 // Mint missing SubnetTAO and SubnetLocked into subnet accounts to make TotalIssuance match in balances and subtensor
-                .saturating_add(migrations::migrate_subnet_balances::migrate_subnet_balances::<T>());
+                .saturating_add(migrations::migrate_subnet_balances::migrate_subnet_balances::<T>())
+                // Fix testnet Subtensor TotalIssuance after the EVM fees issue.
+                .saturating_add(migrations::migrate_fix_total_issuance_evm_fees::migrate_fix_total_issuance_evm_fees::<T>());
             weight
         }
 

pallets/subtensor/src/migrations/migrate_fix_total_issuance_evm_fees.rs

@@ -0,0 +1,45 @@
+use super::*;
+use frame_support::traits::fungible::Inspect;
+use frame_support::weights::Weight;
+
+pub fn migrate_fix_total_issuance_evm_fees<T: Config>() -> Weight {
+    let migration_name = b"migrate_fix_total_issuance_evm_fees".to_vec();
+    let mut weight = T::DbWeight::get().reads(1);
+
+    if HasMigrationRun::<T>::get(&migration_name) {
+        log::info!(
+            "Migration '{:?}' has already run. Skipping.",
+            String::from_utf8_lossy(&migration_name)
+        );
+        return weight;
+    }
+
+    log::info!(
+        "Running migration '{}'",
+        String::from_utf8_lossy(&migration_name)
+    );
+
+    // Fix testnet TotalIssuance after the earlier EVM fees issue caused the
+    // Subtensor pallet's accounting to diverge from the balances pallet.
+    let balances_total_issuance = <T as Config>::Currency::total_issuance();
+    let subtensor_total_issuance_before = TotalIssuance::<T>::get();
+    TotalIssuance::<T>::put(balances_total_issuance);
+    weight = weight.saturating_add(T::DbWeight::get().reads_writes(2, 1));
+
+    log::info!(
+        "Subtensor TotalIssuance fixed for EVM fees issue: previous: {}, new: {}",
+        subtensor_total_issuance_before,
+        balances_total_issuance
+    );
+
+    HasMigrationRun::<T>::insert(&migration_name, true);
+    weight = weight.saturating_add(T::DbWeight::get().writes(1));
+
+    log::info!(
+        target: "runtime",
+        "Migration '{}' completed successfully.",
+        String::from_utf8_lossy(&migration_name)
+    );
+
+    weight
+}

pallets/subtensor/src/migrations/mod.rs

@@ -23,6 +23,7 @@ pub mod migrate_fix_root_claimed_overclaim;
 pub mod migrate_fix_root_subnet_tao;
 pub mod migrate_fix_root_tao_and_alpha_in;
 pub mod migrate_fix_staking_hot_keys;
+pub mod migrate_fix_total_issuance_evm_fees;
 pub mod migrate_init_tao_flow;
 pub mod migrate_init_total_issuance;
 pub mod migrate_kappa_map_to_default;

pallets/subtensor/src/subnets/subnet.rs

@@ -235,6 +235,9 @@ impl<T: Config> Pallet<T> {
 
         let owner_alpha_stake = AlphaBalance::ZERO;
 
+        // With the full lock retained in the reserve, this will normally be zero.
+        let tao_recycled_for_registration = actual_tao_lock_amount.saturating_sub(total_pool_tao);
+
         // Core pool + ownership
         SubnetTAO::<T>::insert(netuid_to_register, total_pool_tao);
         SubnetAlphaIn::<T>::insert(netuid_to_register, total_pool_alpha);
@@ -245,6 +248,15 @@ impl<T: Config> Pallet<T> {
         SubnetAlphaInProvided::<T>::insert(netuid_to_register, AlphaBalance::ZERO);
         SubnetAlphaOut::<T>::insert(netuid_to_register, owner_alpha_stake);
         SubnetVolume::<T>::insert(netuid_to_register, 0u128);
+        RAORecycledForRegistration::<T>::insert(netuid_to_register, tao_recycled_for_registration);
+
+        if tao_recycled_for_registration > TaoBalance::ZERO
+            && let Some(subnet_account_id) = Self::get_subnet_account_id(netuid_to_register)
+        {
+            // The subnet account ID is guaranteed to have adequate balance for this
+            // recycle because of transfer operation earlier. No need to check this result.
+            let _ = Self::recycle_tao(&subnet_account_id, tao_recycled_for_registration);
+        }
 
         if total_pool_tao > TaoBalance::ZERO {
             // Record in TotalStake the initial TAO in the pool.

pallets/subtensor/src/tests/migration.rs

@@ -15,7 +15,7 @@ use frame_support::{
     StorageHasher, Twox64Concat, assert_ok,
     storage::unhashed::{get, get_raw, put, put_raw},
     storage_alias,
-    traits::{StorageInstance, StoredMap},
+    traits::{Currency, StorageInstance, StoredMap, fungible::Inspect},
     weights::Weight,
 };
 use safe_math::SafeDiv;
@@ -4356,3 +4356,41 @@ fn test_migrate_subnet_balances() {
         assert!(HasMigrationRun::<Test>::get(MIGRATION_NAME.to_vec()));
     });
 }
+
+#[test]
+fn test_migrate_fix_total_issuance_evm_fees() {
+    new_test_ext(1).execute_with(|| {
+        const MIGRATION_NAME: &[u8] = b"migrate_fix_total_issuance_evm_fees";
+
+        let account = U256::from(42);
+        let balances_total_issuance = TaoBalance::from(123_456_789_u64);
+        Balances::make_free_balance_be(&account, balances_total_issuance);
+
+        let broken_subtensor_total_issuance = TaoBalance::from(987_654_321_u64);
+        TotalIssuance::<Test>::put(broken_subtensor_total_issuance);
+
+        assert_eq!(Balances::total_issuance(), balances_total_issuance);
+        assert_eq!(
+            TotalIssuance::<Test>::get(),
+            broken_subtensor_total_issuance
+        );
+        assert!(!HasMigrationRun::<Test>::get(MIGRATION_NAME.to_vec()));
+
+        let weight = crate::migrations::migrate_fix_total_issuance_evm_fees::migrate_fix_total_issuance_evm_fees::<Test>();
+
+        assert!(!weight.is_zero(), "weight must be non-zero");
+        assert_eq!(TotalIssuance::<Test>::get(), balances_total_issuance);
+        assert!(HasMigrationRun::<Test>::get(MIGRATION_NAME.to_vec()));
+
+        let second_wrong_value = TaoBalance::from(555_u64);
+        TotalIssuance::<Test>::put(second_wrong_value);
+
+        crate::migrations::migrate_fix_total_issuance_evm_fees::migrate_fix_total_issuance_evm_fees::<Test>();
+
+        assert_eq!(
+            TotalIssuance::<Test>::get(),
+            second_wrong_value,
+            "migration must not run more than once"
+        );
+    });
+}