# Upgrade Guide

This document provides a full guide for upgrading a Cosmos SDK chain from `v0.50.x` to `v0.53.x`.

This guide includes one **required** change and three **optional** features.

After completing this guide, applications will have:

* The `x/protocolpool` module
* The `x/epochs` module
* Unordered Transaction support

## Table of Contents

* [App Wiring Changes (REQUIRED)](#app-wiring-changes-required)
* [Adding ProtocolPool Module (OPTIONAL)](#adding-protocolpool-module-optional)
    * [ProtocolPool Manual Wiring](#protocolpool-manual-wiring)
    * [ProtocolPool DI Wiring](#protocolpool-di-wiring)
* [Adding Epochs Module (OPTIONAL)](#adding-epochs-module-optional)
    * [Epochs Manual Wiring](#epochs-manual-wiring)
    * [Epochs DI Wiring](#epochs-di-wiring)
* [Enable Unordered Transactions (OPTIONAL)](#enable-unordered-transactions-optional)
* [Upgrade Handler](#upgrade-handler)

## App Wiring Changes **REQUIRED**

The `x/auth` module now contains a `PreBlocker` that _must_ be set in the module manager's `SetOrderPreBlockers` method.

```go
app.ModuleManager.SetOrderPreBlockers(
    upgradetypes.ModuleName,
    authtypes.ModuleName, // NEW
)
```

## Adding ProtocolPool Module **OPTIONAL**

:::warning

Using an external community pool such as `x/protocolpool` will cause the following `x/distribution` handlers to return an error:

**QueryService**

* `CommunityPool`

**MsgService**

* `CommunityPoolSpend`
* `FundCommunityPool`

If your services depend on this functionality from `x/distribution`, please update them to use either `x/protocolpool` or your custom external community pool alternatives.

:::

### Manual Wiring

Import the following:

```go
import (
    // ...
    "github.com/cosmos/cosmos-sdk/x/protocolpool"
    protocolpoolkeeper "github.com/cosmos/cosmos-sdk/x/protocolpool/keeper"
    protocolpooltypes "github.com/cosmos/cosmos-sdk/x/protocolpool/types"
)
```

Set the module account permissions.

```go
maccPerms = map[string][]string{
    // ...
    protocolpooltypes.ModuleName:                nil,
    protocolpooltypes.ProtocolPoolEscrowAccount: nil,
}
```

Add the protocol pool keeper to your application struct.

```go
ProtocolPoolKeeper protocolpoolkeeper.Keeper
```

Add the store key:

```go
keys := storetypes.NewKVStoreKeys(
    // ...
    protocolpooltypes.StoreKey,
)
```

Instantiate the keeper.

Make sure to do this before the distribution module instantiation, as you will pass the keeper there next.

```go
app.ProtocolPoolKeeper = protocolpoolkeeper.NewKeeper(
    appCodec,
    runtime.NewKVStoreService(keys[protocolpooltypes.StoreKey]),
    app.AccountKeeper,
    app.BankKeeper,
    authtypes.NewModuleAddress(govtypes.ModuleName).String(),
)
```

Pass the protocolpool keeper to the distribution keeper:

```go
app.DistrKeeper = distrkeeper.NewKeeper(
    appCodec,
    runtime.NewKVStoreService(keys[distrtypes.StoreKey]),
    app.AccountKeeper,
    app.BankKeeper,
    app.StakingKeeper,
    authtypes.FeeCollectorName,
    authtypes.NewModuleAddress(govtypes.ModuleName).String(),
    distrkeeper.WithExternalCommunityPool(app.ProtocolPoolKeeper), // NEW
)
```

Add the protocolpool module to the module manager:

```go
app.ModuleManager = module.NewManager(
    // ...
    protocolpool.NewAppModule(appCodec, app.ProtocolPoolKeeper, app.AccountKeeper, app.BankKeeper),
)
```

Add an entry for SetOrderBeginBlockers, SetOrderEndBlockers, SetOrderInitGenesis, and SetOrderExportGenesis.

```go
app.ModuleManager.SetOrderBeginBlockers(
    // must come AFTER distribution.
    distrtypes.ModuleName,
    protocolpooltypes.ModuleName,
)
```

```go
app.ModuleManager.SetOrderEndBlockers(
    // order does not matter.
    protocolpooltypes.ModuleName,
)
```

```go
app.ModuleManager.SetOrderInitGenesis(
    // order does not matter.
    protocolpooltypes.ModuleName,   
)
```

```go
app.ModuleManager.SetOrderInitGenesis(
    protocolpooltypes.ModuleName, // must be exported before bank.
    banktypes.ModuleName,
)
```

### DI Wiring

Note: _as long as an external community pool keeper (here, `x/protocolpool`) is wired in DI configs, `x/distribution` will automatically use it for its external pool._

First, set up the keeper for the application.

Import the protocolpool keeper:

```go
protocolpoolkeeper "github.com/cosmos/cosmos-sdk/x/protocolpool/keeper"
```

Add the keeper to your application struct:

```go
ProtocolPoolKeeper protocolpoolkeeper.Keeper
```

Add the keeper to the depinject system:

```go
depinject.Inject(
    appConfig,
    &appBuilder,
    &app.appCodec,
    &app.legacyAmino,
    &app.txConfig,
    &app.interfaceRegistry,
    // ... other modules
    &app.ProtocolPoolKeeper, // NEW MODULE!
)
```

Next, set up configuration for the module.

Import the following:

```go
import (
    protocolpoolmodulev1 "cosmossdk.io/api/cosmos/protocolpool/module/v1"
    
    _ "github.com/cosmos/cosmos-sdk/x/protocolpool" // import for side-effects
    protocolpooltypes "github.com/cosmos/cosmos-sdk/x/protocolpool/types"
)
```

The protocolpool module has module accounts that handle funds. Add them to the module account permission configuration:

```go
moduleAccPerms = []*authmodulev1.ModuleAccountPermission{
    // ...
    {Account: protocolpooltypes.ModuleName},
    {Account: protocolpooltypes.ProtocolPoolEscrowAccount},
}
```

Next, add an entry for BeginBlockers, EndBlockers, InitGenesis, and ExportGenesis.

```go
BeginBlockers: []string{
    // ...
    // must be AFTER distribution.
    distrtypes.ModuleName,
    protocolpooltypes.ModuleName,
},
```

```go
EndBlockers: []string{
    // ...
    // order for protocolpool does not matter.
    protocolpooltypes.ModuleName,
},
```

```go
InitGenesis: []string{
    // ... must be AFTER distribution.
    distrtypes.ModuleName,
    protocolpooltypes.ModuleName,
},
```

```go
ExportGenesis: []string{
    // ...
    // Must be exported before x/bank.
    protocolpooltypes.ModuleName, 
    banktypes.ModuleName,
},
```

Lastly, add an entry for protocolpool in the ModuleConfig.

```go
{
    Name:   protocolpooltypes.ModuleName,
    Config: appconfig.WrapAny(&protocolpoolmodulev1.Module{}),
},
```

## Adding Epochs Module **OPTIONAL**

### Manual Wiring

Import the following:

```go
import (
    // ...
    "github.com/cosmos/cosmos-sdk/x/epochs"
    epochskeeper "github.com/cosmos/cosmos-sdk/x/epochs/keeper"
    epochstypes "github.com/cosmos/cosmos-sdk/x/epochs/types"
)
```

Add the epochs keeper to your application struct:

```go
EpochsKeeper epochskeeper.Keeper
```

Add the store key:

```go
keys := storetypes.NewKVStoreKeys(
    // ...
    epochstypes.StoreKey,
)
```

Instantiate the keeper:

```go
app.EpochsKeeper = epochskeeper.NewKeeper(
    runtime.NewKVStoreService(keys[epochstypes.StoreKey]),
    appCodec,
)
```

Set up hooks for the epochs keeper:

To learn how to write hooks for the epoch keeper, see the [x/epoch README](https://github.com/cosmos/cosmos-sdk/blob/main/x/epochs/README.md)

```go
app.EpochsKeeper.SetHooks(
    epochstypes.NewMultiEpochHooks(
        // insert epoch hooks receivers here
        app.SomeOtherModule
    ),
)
```

Add the epochs module to the module manager:

```go
app.ModuleManager = module.NewManager(
    // ...
    epochs.NewAppModule(appCodec, app.EpochsKeeper),
)
```

Add entries for SetOrderBeginBlockers and SetOrderInitGenesis:

```go
app.ModuleManager.SetOrderBeginBlockers(
    // ...
    epochstypes.ModuleName,
)
```

```go
app.ModuleManager.SetOrderInitGenesis(
    // ...
    epochstypes.ModuleName,
)
```

### DI Wiring

First, set up the keeper for the application.

Import the epochs keeper:

```go
epochskeeper "github.com/cosmos/cosmos-sdk/x/epochs/keeper"
```

Add the keeper to your application struct:

```go
EpochsKeeper epochskeeper.Keeper
```

Add the keeper to the depinject system:

```go
depinject.Inject(
    appConfig,
    &appBuilder,
    &app.appCodec,
    &app.legacyAmino,
    &app.txConfig,
    &app.interfaceRegistry,
    // ... other modules
    &app.EpochsKeeper, // NEW MODULE!
)
```

Next, set up configuration for the module.

Import the following:

```go
import (
    epochsmodulev1 "cosmossdk.io/api/cosmos/epochs/module/v1"
    
    _ "github.com/cosmos/cosmos-sdk/x/epochs" // import for side-effects
    epochstypes "github.com/cosmos/cosmos-sdk/x/epochs/types"
)
```

Add an entry for BeginBlockers and InitGenesis:

```go
BeginBlockers: []string{
    // ...
    epochstypes.ModuleName,
},
```

```go
InitGenesis: []string{
    // ...
    epochstypes.ModuleName,
},
```

Lastly, add an entry for epochs in the ModuleConfig:

```go
{
    Name:   epochstypes.ModuleName,
    Config: appconfig.WrapAny(&epochsmodulev1.Module{}),
},
```

## Enable Unordered Transactions **OPTIONAL**

To enable unordered transaction support on an application, the `x/auth` keeper must be supplied with the `WithUnorderedTransactions` option.

Note that unordered transactions require sequence values to be zero, and will **FAIL** if a non-zero sequence value is set.
Please ensure no sequence value is set when submitting an unordered transaction.
Services that rely on prior assumptions about sequence values should be updated to handle unordered transactions.
Services should be aware that when the transaction is unordered, the transaction sequence will always be zero.

```go
	app.AccountKeeper = authkeeper.NewAccountKeeper(
		appCodec,
		runtime.NewKVStoreService(keys[authtypes.StoreKey]),
		authtypes.ProtoBaseAccount,
		maccPerms,
		authcodec.NewBech32Codec(sdk.Bech32MainPrefix),
		sdk.Bech32MainPrefix,
		authtypes.NewModuleAddress(govtypes.ModuleName).String(),
		authkeeper.WithUnorderedTransactions(true), // new option!
	)
```

If using dependency injection, update the auth module config.

```go
		{
			Name: authtypes.ModuleName,
			Config: appconfig.WrapAny(&authmodulev1.Module{
				Bech32Prefix:             "cosmos",
				ModuleAccountPermissions: moduleAccPerms,
				EnableUnorderedTransactions: true, // remove this line if you do not want unordered transactions.
			}),
		},
```

By default, unordered transactions use a transaction timeout duration of 10 minutes and a default gas charge of 2240 gas units.
To modify these default values, pass in the corresponding options to the new `SigVerifyOptions` field in `x/auth's` `ante.HandlerOptions`.

```go
options := ante.HandlerOptions{
    SigVerifyOptions: []ante.SigVerificationDecoratorOption{
        // change below as needed.
        ante.WithUnorderedTxGasCost(ante.DefaultUnorderedTxGasCost),
        ante.WithMaxUnorderedTxTimeoutDuration(ante.DefaultMaxTimeoutDuration),
    },
}
```

```go
anteDecorators := []sdk.AnteDecorator{
	// ... other decorators ...
    ante.NewSigVerificationDecorator(options.AccountKeeper, options.SignModeHandler, options.SigVerifyOptions...), // supply new options
}
```

## Upgrade Handler

The upgrade handler only requires adding the store upgrades for the modules added above.
If your application is not adding `x/protocolpool` or `x/epochs`, you do not need to add the store upgrade.

```go
// UpgradeName defines the on-chain upgrade name for the sample SimApp upgrade
// from v050 to v053.
//
// NOTE: This upgrade defines a reference implementation of what an upgrade
// could look like when an application is migrating from Cosmos SDK version
// v0.50.x to v0.53.x.
const UpgradeName = "v050-to-v053"

func (app SimApp) RegisterUpgradeHandlers() {
    app.UpgradeKeeper.SetUpgradeHandler(
        UpgradeName,
        func(ctx context.Context, _ upgradetypes.Plan, fromVM module.VersionMap) (module.VersionMap, error) {
            return app.ModuleManager.RunMigrations(ctx, app.Configurator(), fromVM)
        },
    )

    upgradeInfo, err := app.UpgradeKeeper.ReadUpgradeInfoFromDisk()
    if err != nil {
        panic(err)
    }

    if upgradeInfo.Name == UpgradeName && !app.UpgradeKeeper.IsSkipHeight(upgradeInfo.Height) {
        storeUpgrades := storetypes.StoreUpgrades{
            Added: []string{
                epochstypes.ModuleName, // if not adding x/epochs to your chain, remove this line.
                protocolpooltypes.ModuleName, // if not adding x/protocolpool to your chain, remove this line.
            },
        }

        // configure store loader that checks if version == upgradeHeight and applies store upgrades
        app.SetStoreLoader(upgradetypes.UpgradeStoreLoader(upgradeInfo.Height, &storeUpgrades))
    }
}
```