Refactor childkeys/parentkeys, add migration to clean state

pallets/subtensor/src/macros/errors.rs

@@ -262,5 +262,7 @@ mod errors {
         UidMapCouldNotBeCleared,
         /// Trimming would exceed the max immune neurons percentage
         TrimmingWouldExceedMaxImmunePercentage,
+        /// Violating the rules of Childkey-Parentkey consistency
+        ChildParentInconsistency,
     }
 }

pallets/subtensor/src/macros/hooks.rs

@@ -150,6 +150,8 @@ mod hooks {
                 .saturating_add(migrations::migrate_subnet_locked::migrate_restore_subnet_locked::<T>())
                 // Migrate subnet burn cost to 2500
                 .saturating_add(migrations::migrate_network_lock_cost_2500::migrate_network_lock_cost_2500::<T>())
+                // 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>());
             weight

pallets/subtensor/src/migrations/migrate_fix_childkeys.rs

@@ -0,0 +1,40 @@
+use super::*;
+use alloc::string::String;
+
+pub fn migrate_fix_childkeys<T: Config>() -> Weight {
+    let migration_name = b"migrate_fix_childkeys".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)
+    );
+
+    ////////////////////////////////////////////////////////
+    // Actual migration
+
+    Pallet::<T>::clean_zero_childkey_vectors(&mut weight);
+    Pallet::<T>::clean_zero_parentkey_vectors(&mut weight);
+    Pallet::<T>::clean_self_loops(&mut weight);
+    Pallet::<T>::repair_child_parent_consistency(&mut weight);
+
+    ////////////////////////////////////////////////////////
+
+    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

@@ -15,6 +15,7 @@ pub mod migrate_crv3_v2_to_timelocked;
 pub mod migrate_delete_subnet_21;
 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_subnet_tao;
 pub mod migrate_fix_root_tao_and_alpha_in;