fix: fix faulty epochs created prior v0.9.0 migration (#198)

contracts/liquidity_hub/fee_distributor/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fee_distributor"
-version = "0.9.0"
+version = "0.9.1"
 authors = ["Kerber0x <[email protected]>"]
 edition.workspace = true
 description = "Contract to distribute the fees collected by the Fee Collector."

contracts/liquidity_hub/fee_distributor/src/contract.rs

@@ -180,10 +180,18 @@ pub fn migrate(mut deps: DepsMut, _env: Env, _msg: MigrateMsg) -> Result<Respons
         });
     }
 
+    set_contract_version(deps.storage, CONTRACT_NAME, CONTRACT_VERSION)?;
+
     if storage_version < Version::parse("0.9.0")? {
         migrations::migrate_to_v090(deps.branch())?;
     }
 
-    set_contract_version(deps.storage, CONTRACT_NAME, CONTRACT_VERSION)?;
+    if storage_version == Version::parse("0.9.0")? {
+        let fees_refund_messages = migrations::migrate_to_v091(deps.branch())?;
+        return Ok(Response::default()
+            .add_messages(fees_refund_messages)
+            .add_attribute("action", "migrate"));
+    }
+
     Ok(Response::default())
 }

contracts/liquidity_hub/fee_distributor/src/migrations.rs

@@ -1,15 +1,20 @@
 #![cfg(not(tarpaulin_include))]
-use crate::state::{CONFIG, EPOCHS};
+
 use cosmwasm_schema::cw_serde;
 use cosmwasm_std::{
-    to_binary, DepsMut, Order, QueryRequest, StdError, StdResult, Timestamp, Uint64, WasmQuery,
+    to_binary, CosmosMsg, DepsMut, Order, QueryRequest, StdError, StdResult, Timestamp,
+    Uint64, WasmQuery,
 };
 use cw_storage_plus::Map;
+
 use white_whale::fee_distributor::Epoch;
+use white_whale::pool_network::asset;
 use white_whale::pool_network::asset::Asset;
 use white_whale::whale_lair::GlobalIndex;
 use white_whale::whale_lair::QueryMsg as LairQueryMsg;
 
+use crate::state::{get_claimable_epochs, CONFIG, EPOCHS};
+
 /// Migrates state from the first iteration, v0.8.* to v0.9.0, which includes the global index in
 /// the Epoch. This was done to fix bonding issues.
 pub fn migrate_to_v090(deps: DepsMut) -> Result<(), StdError> {
@@ -61,3 +66,41 @@ pub fn migrate_to_v090(deps: DepsMut) -> Result<(), StdError> {
 
     Ok(())
 }
+
+/// Fixes the broken state for Epochs created prior to the v0.9.0 migration.
+pub fn migrate_to_v091(deps: DepsMut) -> Result<Vec<CosmosMsg>, StdError> {
+    let claimable_epochs = get_claimable_epochs(deps.as_ref())?;
+
+    // 14 June 2023 16:00:00 UTC
+    let migration_timestamp = Timestamp::from_seconds(1686758400);
+    let mut faulty_epochs = claimable_epochs
+        .epochs
+        .into_iter()
+        .filter(|epoch| epoch.start_time.seconds() < migration_timestamp.seconds())
+        .collect::<Vec<Epoch>>();
+
+    let fee_collector_addr = CONFIG.load(deps.storage)?.fee_collector_addr;
+
+    // collect all available funds on faulty epochs and send them back to the fee collector, to be
+    // redistributed on the next (new) epoch
+
+    let mut total_fees: Vec<Asset> = vec![];
+    for epoch in faulty_epochs.iter_mut() {
+        total_fees = asset::aggregate_assets(total_fees, epoch.available.clone())?;
+
+        // set the available fees of this faulty epoch to zero
+        epoch.available = vec![];
+
+        // save the faulty epoch in the state
+        EPOCHS.save(deps.storage, &epoch.id.to_be_bytes(), &epoch)?;
+    }
+
+    // create messages to send total_fees back to the fee collector
+    let mut messages = vec![];
+
+    for fee in total_fees {
+        messages.push(fee.into_msg(fee_collector_addr.clone())?);
+    }
+
+    Ok(messages)
+}