From b25568583e3ed306ac3c51cc17641201378a2a2e Mon Sep 17 00:00:00 2001
From: Ethan Frey <ethanfrey@users.noreply.github.com>
Date: Mon, 31 Jan 2022 13:45:08 +0100
Subject: [PATCH] Perform proper migration logic

---
 contracts/cw20-ics20/src/contract.rs   | 21 +++++++++++++++++++--
 contracts/cw20-ics20/src/lib.rs        |  1 +
 contracts/cw20-ics20/src/migrations.rs | 16 ++++++++++++++++
 3 files changed, 36 insertions(+), 2 deletions(-)
 create mode 100644 contracts/cw20-ics20/src/migrations.rs

diff --git a/contracts/cw20-ics20/src/contract.rs b/contracts/cw20-ics20/src/contract.rs
index dbb52f015..cbcd8767b 100644
--- a/contracts/cw20-ics20/src/contract.rs
+++ b/contracts/cw20-ics20/src/contract.rs
@@ -192,26 +192,43 @@ pub fn execute_allow(
 }
 
 #[cfg_attr(not(feature = "library"), entry_point)]
-pub fn migrate(deps: DepsMut, _env: Env, _msg: MigrateMsg) -> Result<Response, ContractError> {
+pub fn migrate(mut deps: DepsMut, _env: Env, _msg: MigrateMsg) -> Result<Response, ContractError> {
     let version: Version = CONTRACT_VERSION.parse().map_err(from_semver)?;
     let stored = get_contract_version(deps.storage)?;
     let storage_version: Version = stored.version.parse().map_err(from_semver)?;
 
+    // First, ensure we are working from an equal or older version of this contract
+    // wrong type
     if CONTRACT_NAME != stored.contract {
         return Err(ContractError::CannotMigrate {
             previous_contract: stored.contract,
         });
     }
+    // existing one is newer
     if storage_version > version {
         return Err(ContractError::CannotMigrateVersion {
             previous_version: stored.version,
         });
     }
 
+    // Then, run the proper migration
+    // unsupported old version
+    if storage_version < "0.11.1".parse().map_err(from_semver)? {
+        return Err(ContractError::CannotMigrateVersion {
+            previous_version: stored.version,
+        });
+    }
     // for 0.12.0-alpha1 or earlier, migrate from the config.gov_contract to ADMIN
     if storage_version <= "0.12.0-alpha1".parse().map_err(from_semver)? {
-        // DO migration
+        // Do v1 migration
+        let old_config = crate::migrations::v1::CONFIG.load(deps.storage)?;
+        ADMIN.set(deps.branch(), Some(old_config.gov_contract))?;
+        let config = Config {
+            default_timeout: old_config.default_timeout,
+        };
+        CONFIG.save(deps.storage, &config)?;
     }
+    // otherwise no migration (yet)
 
     if storage_version < version {
         // we don't need to save anything if migrating from the same version
diff --git a/contracts/cw20-ics20/src/lib.rs b/contracts/cw20-ics20/src/lib.rs
index 5e579aafa..b9ceef245 100644
--- a/contracts/cw20-ics20/src/lib.rs
+++ b/contracts/cw20-ics20/src/lib.rs
@@ -2,6 +2,7 @@ pub mod amount;
 pub mod contract;
 mod error;
 pub mod ibc;
+mod migrations;
 pub mod msg;
 pub mod state;
 mod test_helpers;
diff --git a/contracts/cw20-ics20/src/migrations.rs b/contracts/cw20-ics20/src/migrations.rs
new file mode 100644
index 000000000..888df9418
--- /dev/null
+++ b/contracts/cw20-ics20/src/migrations.rs
@@ -0,0 +1,16 @@
+// v1 format is anything older than 0.12.0
+pub mod v1 {
+    use schemars::JsonSchema;
+    use serde::{Deserialize, Serialize};
+
+    use cosmwasm_std::Addr;
+    use cw_storage_plus::Item;
+
+    #[derive(Serialize, Deserialize, Clone, PartialEq, JsonSchema, Debug)]
+    pub struct ConfigV1 {
+        pub default_timeout: u64,
+        pub gov_contract: Addr,
+    }
+
+    pub const CONFIG: Item<ConfigV1> = Item::new("ics20_config");
+}