Bugfix for: hotkey_swap on a single subnet wipes all root dividend accumulations

pallets/subtensor/src/macros/hooks.rs

@@ -166,7 +166,9 @@ mod hooks {
                 // Fix staking hot keys
                 .saturating_add(migrations::migrate_fix_staking_hot_keys::migrate_fix_staking_hot_keys::<T>())
                 // Migrate coldkey swap scheduled to announcements
-                .saturating_add(migrations::migrate_coldkey_swap_scheduled_to_announcements::migrate_coldkey_swap_scheduled_to_announcements::<T>());
+                .saturating_add(migrations::migrate_coldkey_swap_scheduled_to_announcements::migrate_coldkey_swap_scheduled_to_announcements::<T>())
+                // Fix RootClaimed overclaim caused by single-subnet hotkey swap bug
+                .saturating_add(migrations::migrate_fix_root_claimed_overclaim::migrate_fix_root_claimed_overclaim::<T>());
             weight
         }
 

pallets/subtensor/src/migrations/migrate_fix_root_claimed_overclaim.rs

@@ -0,0 +1,58 @@
+use super::*;
+use frame_support::pallet_prelude::Weight;
+use frame_system::pallet_prelude::BlockNumberFor;
+use scale_info::prelude::string::String;
+
+/// Fixes the consequences of a bug in `perform_hotkey_swap_on_one_subnet` where
+/// `transfer_root_claimable_for_new_hotkey` unconditionally transferred the **entire**
+/// `RootClaimable` BTreeMap (all subnets) from the old hotkey to the new hotkey, even
+/// during a single-subnet swap.
+///
+/// This left the old hotkey with:
+///   - `RootClaimable[old_hotkey]` = empty (wiped for ALL subnets)
+///   - `RootClaimed[(subnet, old_hotkey, coldkey)]` = old watermarks (for non-swapped subnets)
+///
+/// Resulting in `owed = claimable_rate * root_stake - root_claimed = 0 - positive = negative → 0`,
+/// effectively freezing root dividends for the old hotkey.
+///
+/// Remediation: restore the pre-swap `RootClaimable` rates (from chain history snapshots)
+/// back to the affected old_hotkeys, excluding subnets that were legitimately swapped.
+/// This adds the snapshot rates to whatever has re-accumulated since the bug, making
+/// `owed = (restored_rate + new_increments) * stake - claimed ≈ new_increments * stake > 0`.
+pub fn migrate_fix_root_claimed_overclaim<T: Config>() -> Weight {
+    let migration_name = b"migrate_fix_root_claimed_overclaim".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)
+    );
+
+    // Only run on mainnet.
+    // Mainnet genesis: 0x2f0555cc76fc2840a25a6ea3b9637146806f1f44b090c175ffde2a7e5ab36c03
+    let genesis_hash = frame_system::Pallet::<T>::block_hash(BlockNumberFor::<T>::zero());
+    let genesis_bytes = genesis_hash.as_ref();
+    let mainnet_genesis =
+        hex_literal::hex!("2f0555cc76fc2840a25a6ea3b9637146806f1f44b090c175ffde2a7e5ab36c03");
+    if genesis_bytes == mainnet_genesis {
+        // TODO
+    }
+
+    // Mark migration as completed
+    HasMigrationRun::<T>::insert(&migration_name, true);
+    weight.saturating_accrue(T::DbWeight::get().writes(1));
+
+    log::info!(
+        "Migration 'migrate_fix_root_claimed_overclaim' completed."
+    );
+
+    weight
+}

pallets/subtensor/src/migrations/mod.rs

@@ -18,6 +18,7 @@ pub mod migrate_delete_subnet_3;
 pub mod migrate_disable_commit_reveal;
 pub mod migrate_fix_childkeys;
 pub mod migrate_fix_is_network_member;
+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;

pallets/subtensor/src/swap/swap_hotkey.rs

@@ -561,16 +561,9 @@ impl<T: Config> Pallet<T> {
             weight.saturating_accrue(T::DbWeight::get().reads(old_alpha_values_v2.len() as u64));
             weight.saturating_accrue(T::DbWeight::get().writes(old_alpha_values_v2.len() as u64));
 
-            // 9.1. Transfer root claimable
-            Self::transfer_root_claimable_for_new_hotkey(old_hotkey, new_hotkey);
-
             // 9.2. Insert the new alpha values.
             for ((coldkey, netuid_alpha), alpha) in old_alpha_values {
                 if netuid == netuid_alpha {
-                    Self::transfer_root_claimed_for_new_keys(
-                        netuid, old_hotkey, new_hotkey, &coldkey, &coldkey,
-                    );
-
                     let new_alpha = Alpha::<T>::take((new_hotkey, &coldkey, netuid));
                     Alpha::<T>::remove((old_hotkey, &coldkey, netuid));
 
@@ -596,10 +589,6 @@ impl<T: Config> Pallet<T> {
 
             for ((coldkey, netuid_alpha), alpha) in old_alpha_values_v2 {
                 if netuid == netuid_alpha {
-                    Self::transfer_root_claimed_for_new_keys(
-                        netuid, old_hotkey, new_hotkey, &coldkey, &coldkey,
-                    );
-
                     let new_alpha_v2 = AlphaV2::<T>::take((new_hotkey, &coldkey, netuid));
                     AlphaV2::<T>::remove((old_hotkey, &coldkey, netuid));
                     AlphaV2::<T>::insert(
@@ -620,6 +609,34 @@ impl<T: Config> Pallet<T> {
                     }
                 }
             }
+
+            // 9.3. Transfer root claimable and root claimed only for the root subnet
+            // NOTE: we shouldn't transfer root claimable and root claimed for other subnets,
+            // otherwise root stakers won't be able to receive dividends.
+            if netuid == NetUid::ROOT {
+                Self::transfer_root_claimable_for_new_hotkey(old_hotkey, new_hotkey);
+                weight.saturating_accrue(T::DbWeight::get().reads_writes(2, 2));
+
+                // After transfer, new_hotkey has the full RootClaimable map.
+                // We use it to know which subnets have outstanding claims.
+                let subnets: Vec<NetUid> = RootClaimable::<T>::get(new_hotkey)
+                    .keys()
+                    .copied()
+                    .collect();
+
+                for subnet in subnets {
+                    let claimed_coldkeys: Vec<T::AccountId> =
+                        RootClaimed::<T>::iter_prefix((subnet, old_hotkey))
+                            .map(|(coldkey, _)| coldkey)
+                            .collect();
+
+                    for coldkey in claimed_coldkeys {
+                        Self::transfer_root_claimed_for_new_keys(
+                            subnet, old_hotkey, new_hotkey, &coldkey, &coldkey,
+                        );
+                    }
+                }
+            }
         }
 
         Ok(())

pallets/subtensor/src/tests/claim_root.rs

@@ -1284,22 +1284,19 @@ fn test_claim_root_with_swap_hotkey() {
             false,
         ));
 
-        // Check swapped keys claimed values
-
+        // Check swapped keys claimed values.
         assert_eq!(
-            0u128,
+            u128::from(new_stake), // It shouldn't change, because we didn't swap the root hotkey
             RootClaimed::<Test>::get((netuid, &hotkey, &coldkey,))
         );
         assert_eq!(
-            u128::from(new_stake),
+            0u128,
             RootClaimed::<Test>::get((netuid, &new_hotkey, &coldkey,))
         );
 
-        assert!(!RootClaimable::<Test>::get(hotkey).contains_key(&netuid));
+        assert!(RootClaimable::<Test>::get(hotkey).contains_key(&netuid));
 
-        let _new_claimable = *RootClaimable::<Test>::get(new_hotkey)
-            .get(&netuid)
-            .expect("claimable must exist at this point");
+        assert!(!RootClaimable::<Test>::get(new_hotkey).contains_key(&netuid));
     });
 }
 

pallets/subtensor/src/tests/swap_hotkey_with_subnet.rs

@@ -13,7 +13,7 @@ use share_pool::SafeFloat;
 use sp_core::{Get, H160, H256, U256};
 use sp_runtime::SaturatedConversion;
 use std::collections::BTreeSet;
-use substrate_fixed::types::U64F64;
+use substrate_fixed::types::{I96F32, U64F64};
 
 // SKIP_WASM_BUILD=1 RUST_LOG=debug cargo test --test swap_hotkey_with_subnet -- test_swap_owner --exact --nocapture
 #[test]
@@ -2501,21 +2501,17 @@ fn test_revert_claim_root_with_swap_hotkey() {
         ));
 
         assert_eq!(
-            RootClaimed::<Test>::get((netuid, &hk1, &coldkey)),
+            RootClaimed::<Test>::get((netuid, &hk2, &coldkey)),
             0u128,
-            "hk1 RootClaimed must be zero after swap"
+            "hk2 RootClaimed must be zero after swap"
         );
         assert_eq!(
-            RootClaimed::<Test>::get((netuid, &hk2, &coldkey)),
+            RootClaimed::<Test>::get((netuid, &hk1, &coldkey)),
             hk1_root_claimed,
             "hk2 must have hk1's RootClaimed after swap"
         );
-        assert!(!RootClaimable::<Test>::get(hk1).contains_key(&netuid));
-        assert_eq!(
-            *RootClaimable::<Test>::get(hk2).get(&netuid).unwrap(),
-            hk1_claimable,
-            "hk2 must have hk1's RootClaimable after swap"
-        );
+        assert!(RootClaimable::<Test>::get(hk1).contains_key(&netuid));
+        assert!(!RootClaimable::<Test>::get(hk2).contains_key(&netuid));
 
         // Revert: hk2 -> hk1
         step_block(20);

runtime/src/lib.rs

@@ -1117,7 +1117,7 @@ parameter_types! {
     // 0 days
     pub const InitialStartCallDelay: u64 = 0;
     pub const SubtensorInitialKeySwapOnSubnetCost: TaoBalance = TaoBalance::new(1_000_000); // 0.001 TAO
-    pub const HotkeySwapOnSubnetInterval : BlockNumber = 24 * 60 * 60 / 12; // 1 day
+    pub const HotkeySwapOnSubnetInterval : BlockNumber = prod_or_fast!(24 * 60 * 60 / 12, 1); // 1 day
     pub const LeaseDividendsDistributionInterval: BlockNumber = 100; // 100 blocks
     pub const MaxImmuneUidsPercentage: Percent = Percent::from_percent(80);
     pub const EvmKeyAssociateRateLimit: u64 = EVM_KEY_ASSOCIATE_RATELIMIT;