migrate kappa to default

Author: JohnReedV

pallets/subtensor/src/macros/hooks.rs

@@ -153,7 +153,9 @@ mod hooks {
                 // Cleanup child/parent keys
                 .saturating_add(migrations::migrate_fix_childkeys::migrate_fix_childkeys::<T>())
                 // Migrate AutoStakeDestinationColdkeys
-                .saturating_add(migrations::migrate_auto_stake_destination::migrate_auto_stake_destination::<T>());
+                .saturating_add(migrations::migrate_auto_stake_destination::migrate_auto_stake_destination::<T>())
+                // Migrate Kappa to default (0.5)
+                .saturating_add(migrations::migrate_kappa_map_to_default::migrate_kappa_map_to_default::<T>());
             weight
         }
 

pallets/subtensor/src/migrations/migrate_kappa_map_to_default.rs

@@ -0,0 +1,60 @@
+use super::*;
+use frame_support::{storage::IterableStorageMap, traits::Get, weights::Weight};
+use log;
+use scale_info::prelude::string::String;
+
+pub fn migrate_kappa_map_to_default<T: Config>() -> Weight {
+    let mig_name: Vec<u8> = b"kappa_map_to_default".to_vec();
+
+    // 1 read for the HasMigrationRun flag
+    let mut total_weight = T::DbWeight::get().reads(1);
+
+    // Run once guard
+    if HasMigrationRun::<T>::get(&mig_name) {
+        log::info!(
+            "Migration '{}' already executed - skipping",
+            String::from_utf8_lossy(&mig_name)
+        );
+        return total_weight;
+    }
+
+    log::info!("Running migration '{}'", String::from_utf8_lossy(&mig_name));
+
+    let target: u16 = DefaultKappa::<T>::get();
+
+    let mut reads: u64 = 0;
+    let mut writes: u64 = 0;
+    let mut visited: u64 = 0;
+    let mut updated: u64 = 0;
+    let mut unchanged: u64 = 0;
+
+    for (netuid, current) in Kappa::<T>::iter() {
+        visited += 1;
+        reads += 1;
+
+        if current != target {
+            Kappa::<T>::insert(netuid, target);
+            writes += 1;
+            updated += 1;
+        } else {
+            unchanged += 1;
+        }
+    }
+
+    total_weight = total_weight.saturating_add(T::DbWeight::get().reads_writes(reads, writes));
+
+    log::info!(
+        "Kappa migration summary: visited={visited}, updated={updated}, unchanged={unchanged}, target_default={}",
+        target
+    );
+
+    HasMigrationRun::<T>::insert(&mig_name, true);
+    total_weight = total_weight.saturating_add(T::DbWeight::get().writes(1));
+
+    log::info!(
+        "Migration '{}' completed",
+        String::from_utf8_lossy(&mig_name)
+    );
+
+    total_weight
+}

pallets/subtensor/src/migrations/mod.rs

@@ -21,6 +21,7 @@ pub mod migrate_fix_root_subnet_tao;
 pub mod migrate_fix_root_tao_and_alpha_in;
 pub mod migrate_identities_v2;
 pub mod migrate_init_total_issuance;
+pub mod migrate_kappa_map_to_default;
 pub mod migrate_network_immunity_period;
 pub mod migrate_network_lock_cost_2500;
 pub mod migrate_network_lock_reduction_interval;

pallets/subtensor/src/tests/migration.rs

@@ -2171,3 +2171,80 @@ fn test_migrate_network_lock_cost_2500_sets_price_and_decay() {
         );
     });
 }
+
+#[test]
+fn test_migrate_kappa_map_to_default() {
+    new_test_ext(1).execute_with(|| {
+        // ------------------------------
+        // 0. Constants / helpers
+        // ------------------------------
+        const MIG_NAME: &[u8] = b"kappa_map_to_default";
+
+        let default: u16 = DefaultKappa::<Test>::get();
+        let not_default: u16 = default.wrapping_add(1);
+
+        // Choose a few netuids to exercise both "changed" and "unchanged" paths
+        let n0: u16 = 0;
+        let n1: u16 = 1;
+        let n2: u16 = 42;
+
+        // ------------------------------
+        // 1. Pre-state: seed non-default & default entries
+        // ------------------------------
+        Kappa::<Test>::insert(n0, not_default); // will need update
+        Kappa::<Test>::insert(n1, default); // already default
+        Kappa::<Test>::insert(n2, not_default); // will need update
+
+        assert_eq!(
+            Kappa::<Test>::get(n0),
+            not_default,
+            "precondition failed: Kappa[n0] should be non-default before migration"
+        );
+        assert_eq!(
+            Kappa::<Test>::get(n1),
+            default,
+            "precondition failed: Kappa[n1] should be default before migration"
+        );
+        assert_eq!(
+            Kappa::<Test>::get(n2),
+            not_default,
+            "precondition failed: Kappa[n2] should be non-default before migration"
+        );
+
+        assert!(
+            !HasMigrationRun::<Test>::get(MIG_NAME.to_vec()),
+            "migration flag should be false before run"
+        );
+
+        // ------------------------------
+        // 2. Run migration
+        // ------------------------------
+        let w =
+            crate::migrations::migrate_kappa_map_to_default::migrate_kappa_map_to_default::<Test>();
+        assert!(!w.is_zero(), "weight must be non-zero");
+
+        // ------------------------------
+        // 3. Verify results
+        // ------------------------------
+        assert!(
+            HasMigrationRun::<Test>::get(MIG_NAME.to_vec()),
+            "migration flag not set"
+        );
+
+        assert_eq!(
+            Kappa::<Test>::get(n0),
+            default,
+            "Kappa[n0] should be reset to the configured default"
+        );
+        assert_eq!(
+            Kappa::<Test>::get(n1),
+            default,
+            "Kappa[n1] should remain at the configured default"
+        );
+        assert_eq!(
+            Kappa::<Test>::get(n2),
+            default,
+            "Kappa[n2] should be reset to the configured default"
+        );
+    });
+}