# Polkadot Release Analysis v0.9.34

:warning: ***The following report is not an exhaustive list of changes included in the release, but a set of changes that we felt deserved to be highlighted due to their impact on the Polkadot ecosystem builders.***

***Please do not stop reading the [release notes v0.9.34](https://github.com/paritytech/polkadot/releases/tag/v0.9.34). This report is complementary to the changelogs, not a replacement.***

***Highlights are categorized into High Impact, Medium Impact, and Low Impact for ease of navigation.***

# Summary

One PR in this release has been flagged by the Release Analysis team as high impact for Polkadot Builders.

This release contains several updates to the newly rolled out OpenGov governance system among various other medium and low impact PR's.

This is a runtime-only release. No node client is released.

<br/>

## Runtimes built on release v0.9.34

- **Westend v9340**
- **Kusama v9340**
- **Polkadot v9340**

As stated in the release notes:

*This polkadot runtime replaces runtime 9320 and 9330.
This kusama runtime replaces runtime 9330.*

<br/>

---
# ❗️High Impact

### ed25519_verify: Support using dalek for historical blocks
PR: https://github.com/paritytech/substrate/pull/12661

Switching to `ed25519-zebra` was a breaking change. `ed25519-zebra` is more permissive when it comes to the verification of signatures. This means that some chains may fail to sync from genesis when using `ed25519-zebra`.

**How this impacts Polkadot builders?**

If you are aware that the chain that you are syncing from may be affected by this change, this PR includes an extension that can be registered to the runtime execution environment to signal that `ed25519-dalek` should be used for verification. In this way the blocks that should be verified by dalek will be verified using the correct library.

The extension can be registered in the following way directly after the client is created:

use sc_client_api::ExecutorProvider;
client.execution_extensions().set_extensions_factory(
    // Let the `UseDalekExt` extension being registered for each runtime invocation
    // until the execution happens in the context of block `1000`.
    sc_client_api::execution_extensions::ExtensionBeforeBlock::<Block, UseDalekExt>::new(1000)
);

Note that in the above example we know that prior to block 1000, all blocks should be verified by `ed25519-dalek` instead of `ed25519-zebra`. From 1000 on, they will be then verified using `ed25519-zebra`.

---
# ⚠️ Medium Impact

### Asset Pallet: Support repeated destroys to safely destroy large assets
PR: https://github.com/paritytech/substrate/pull/12310

*Cumulus Companion PR: [PR #1742](https://github.com/paritytech/cumulus/pull/1742)*

This PR is the part of [#Issue 12275](https://github.com/paritytech/substrate/issues/12275).

**Why is this change interesting for builders?**

[Assets](https://docs.rs/pallet-assets/latest/pallet_assets/) pallet has a `destroy` function to destroy an entire asset class. This function has some [issues](https://github.com/paritytech/substrate/issues/12275), particularly when we destroy an asset with a large number of accounts, it leads to a weight which exceeds the maximum block limit.

This PR is an attempt to fix this issue.

**How this impacts Polkadot builders?**

As part of this PR, `destroy` function has been broken into four new extrinsics. This is well described in PR description. Due to these changes, this PR also adds migration for the same.

A new constant type `RemoveItemsLimit` has also been introduced in Assets pallet’s Config trait.

If you are using Asset pallet in your runtime, you have to add this new config type, otherwise runtime compilation will fail because of missing type error.

impl pallet_assets::Config for Runtime {
	// Other Config types
	type RemoveItemsLimit = ConstU32<1000>;
	
}

---

### Remove the wasmtime feature flag
PR: https://github.com/paritytech/substrate/pull/12684

Polkadot companion PR: https://github.com/paritytech/polkadot/pull/6268
Cumulus companion PR: https://github.com/paritytech/cumulus/pull/1861

[PR #12486](https://github.com/paritytech/substrate/pull/12486) enabled `wasmtime` by default. However, the flag for it was still there. This PR removes the flag. Now `wasmtime` will be unconditionally compiled in.

Any downstream project that depends on Substrate and which is used to specify the wasmtime feature flag in its dependencies will now need to remove it.

---

### Add with_weight extrinsic
PR: https://github.com/paritytech/substrate/pull/12848

Adds to **pallet utility** the possibility of dispatching any extrinsic with custom weight. This PR introduces to said pallet a new extrinsic, `with_weight`. The dispatch origin for this call must be `Root`. It won't check the weight of the call, and instead allows the `Root` origin to specify the weight of the call.

Having the possibility for such an option has raised importance lately, [after some changes to pallet scheduler](https://github.com/paritytech/substrate/pull/11649), it was found that in scenarios like executing a runtime upgrade, the capacity for overriding the call's weight could avoid problems like the runtime upgrade not being executed due to being considered over-weight.

---

### API for registering inactive funds
PR: https://github.com/paritytech/substrate/pull/12813

This PR introduces the concept of active and inactive funds within the total of the issuance, dividing it into two concepts, `InactiveIssuance` and `ActiveIssuance`.

On one side, we can find `InactiveIssuance` as a storage item on `pallet-balances`

/// The total units of outstanding deactivated balance in the system.
#[pallet::storage]
#[pallet::getter(fn inactive_issuance)]
#[pallet::whitelist_storage]
pub type InactiveIssuance<T: Config<I>, I: 'static = ()> =
    StorageValue<_, T::Balance, ValueQuery>;

This should generally be used rather than `TotalIssuance`.

Not only that but it also introduces `ActiveIssuanceOf`

// A non-const `Get` implementation parameterised by a `Currency` impl which provides the result
/// of `active_issuance`.
pub struct ActiveIssuanceOf<C: Currency<A>, A>(sp_std::marker::PhantomData<(C, A)>);
impl<C: Currency<A>, A> Get<C::Balance> for ActiveIssuanceOf<C, A> {
	fn get() -> C::Balance {
		C::active_issuance()
	}
}

What is an example of funds that could be considered as inactive? Well, some funds from Treasury could fit into this definition. Take a look at the following storage item inside the `treasury-pallet`:

/// The amount which has been reported as inactive to Currency.
#[pallet::storage]
pub type Inactive<T: Config<I>, I: 'static = ()> = StorageValue<_, BalanceOf<T, I>, ValueQuery>;

Relevant migrations are in place along with this change.

---

### Allow Sufficient Assets for XCM Fee Payment on Statemint
PR: https://github.com/paritytech/cumulus/pull/1910

This PR adds a new configuration to `Trader` in `xcm_executor` for Statemint runtime.
Appending the `Trader` configuration with `TakeFirstAssetTrader` allows execution to be paid with sufficient assets existing in pallet-assets.

This change was applied previously to Statemine (on Kusama), and now this will also be available in Statemint (on Polkadot).

---

# ℹ️ Low Impact

### Add Offchain Worker to Parachain Config by Default
PR: https://github.com/paritytech/cumulus/pull/1860

To make off-chain data integration secure and more efficient, Substrate provides off-chain workers. Off-chain workers allow your Substrate node to offload tasks that take too long or too much CPU / memory resources to compute, or have a non-deterministic result.

This PR enables Offchain workers in the Cumulus parachain template by default.

### pallet-balances: Fix inactive funds migration
PR: https://github.com/paritytech/substrate/pull/12840

After the inclusion of [PR #12813](https://github.com/paritytech/substrate/pull/12813) that introduced `ActiveIssuanceOf`, this PR includes a migration for `pallet-balances` where it sets `storage_version` attribute for the `Pallet`. At the same time, the migration will take the addition of balances from a list of provided accounts as a parameter and mark the resulting balance as inactive using `deactivate`.

### OpenGov: Abstentions
PR: https://github.com/paritytech/substrate/pull/12842

**How this impacts Polkadot builders?**

This PR should not affect any builder that is not working on a governance system based on [OpenGov](https://medium.com/polkadot-network/gov2-polkadots-next-generation-of-decentralised-governance-4d9ef657d11b) as it only includes new tweaks on how this system works. As of writing, [OpenGov](https://medium.com/polkadot-network/gov2-polkadots-next-generation-of-decentralised-governance-4d9ef657d11b) is present on Kusama.

**Why is this change interesting for builders?**

*Note this change is interesting for the whole of the ecosystem.*
`SplitAbstain` variant has been added into `AccountVote` enum so users can still show paritcipation without affecting the result of the voting.
This is important as in a case where one is neither for or against a proposal, it is possible to `abstain`, making a vote count as support for it, and so helping it to close faster, but not adding to the count of `aye` or `nay` votes.

### OpenGov improvements for Kusama
PR: https://github.com/paritytech/polkadot/pull/6372

**Why is this change interesting for builders?**

Now that [OpenGov](https://medium.com/polkadot-network/gov2-polkadots-next-generation-of-decentralised-governance-4d9ef657d11b) is live on the Kusama network, this PR includes some improvements to the [OpenGov](https://medium.com/polkadot-network/gov2-polkadots-next-generation-of-decentralised-governance-4d9ef657d11b) governance system.

Some of the changes come from the suggestions/improvements that were requested on the Polkadot Forum. You can find the discussion [here](https://forum.polkadot.network/t/community-suggestions-and-requests-for-the-opengov-model-on-kusama/1179).

This PR also introduces migrations for Crowdloan and XCM checking account for all chains (Polkadot, Kusama, Rococo, and Westend).

### Update DefaultNoBound derive macro
PR: https://github.com/paritytech/substrate/pull/12723

Among different fixes and improvements, this PR updates `DefaultNoBound` derive macro to follow rust [RFC 3107](https://github.com/rust-lang/rust/issues/87517), changing the behaviour of the macro from choosing always the first variant as default, to using the variant annotated with `#[default]`.
`#[default]` attribute is now required.

**How to use**

The following is an example of how an enum which uses `DefaultNoBound` derive macro looks like:

// source: https://github.com/paritytech/substrate/blob/master/frame/transaction-payment/asset-tx-payment/src/lib.rs
#[derive(Encode, Decode, DefaultNoBound, TypeInfo)]
pub enum InitialPayment<T: Config> {
	/// No initial fee was payed.
	#[default]
	Nothing,
	/// The initial fee was payed in the native currency.
	Native(LiquidityInfoOf<T>),
	/// The initial fee was payed in an asset.
	Asset(CreditOf<T::AccountId, T::Fungibles>),
}

`InitialPayment::Nothing` will be the default variant for this enum.

### Support OpenGov Calls in Proxy Definitions
PR: https://github.com/paritytech/polkadot/pull/6366

This PR is the part of [#Issue 6333](https://github.com/paritytech/polkadot/issues/6333).

**Why is this change interesting for builders?**

Proxy pallet filters the calls a proxy account can dispatch based on the proxy type. In the runtime, you can restrict transactions for a proxy account using the following proxy types:

* Any
* NonTransfer
* Governance
* Staking
* IdentityJudgement
* CancelProxy
* Auction

At the moment, only Gov v1 pallets are included in Kusama runtime proxy definition. This PR adds OpenGov pallets into the proxy definitions.

### Fix the light client protocol protobuf schema
PR: https://github.com/paritytech/substrate/pull/12732

Before this PR, if a node received a "light client request" which could not be served the message would send back an empty proof. This has been amended to the correct intended behaviour which is to send a response without a proof and the response should indicate the type of response it is.

Additionally, this PR also switches the schema to protobuf 2. Reason being that each field is either explicitly required or optional, so the exact information that is being sent is clearer.

### Make public is_passing and ReferendumStatus
PR: https://github.com/paritytech/substrate/pull/12667

Pallet referenda now exposes read access to `fn is_passing()` ( a private function ) as `pub fn is_referendum_passing(ReferendumIndex)` which will return whether the referendum is passing. This rederendum must be ongoing and its track must exist.
This PR also changes to public the visibility of the fields from the following structs:

- `DecidingStatus`
- `Deposit`
- `ReferendumStatus`

> _find the definition of these structs in [frame/referenda/src/types.rs](https://github.com/paritytech/substrate/blob/master/frame/referenda/src/types.rs)_

with the intention that this information can be accessed from, for instance, precompiles and allows different collectives to participate in different referenda as they fit their liking, independently of how these collectives are technically implemented.

### Make Gov2 Curve::threshold fn public
PR: https://github.com/paritytech/substrate/pull/12814

In the very same lines as [PR #12667](https://github.com/paritytech/substrate/pull/12667), this PR changes the visibility of `fn threshold` to public, so other modules can access this information. The relevant information here is the value of a certain threshold curve for a given _x_. This function can be found in [_frame/referenda/src/types.rs_](https://github.com/paritytech/substrate/blob/master/frame/referenda/src/types.rs)

### New root_testing pallet
PR: https://github.com/paritytech/substrate/pull/12451

To keep the codebase tidy and coherent, this pallet moves the function `fill_block` from `root_offences_pallet` to a new pallet, `root_testing` which at the moment only hosts this function as an extrinsic, and enables the user to fill a block up to a given ratio.

This pallet should only be used for testing purposes.

### Allow other pallets to check asset ids.
PR: https://github.com/paritytech/substrate/pull/12666

This PR implements `InspectEnumerable` for assets pallet. Which allows other pallets to know what assets are in existence.

The `InspectEnumerable` trait:

/// Interface for enumerating assets in existence or owned by a given account.
pub trait InspectEnumerable<AccountId>: Inspect<AccountId> {
	type AssetsIterator;

	/// Returns an iterator of the collections in existence.
	fn asset_ids() -> Self::AssetsIterator;
}

We can see that, `fn asset_ids()` will return an `AssetsIterator`. Note that iterating this list invokes a storage read per item.

### Move WeightCounter to sp-weights
PR: https://github.com/paritytech/substrate/pull/12603

`WeightCounter` has been renamed to `WeightMeter` and moved into sp-weights.
Can be used to check if enough weight for an operation is available before committing to it.

use sp_weights::{Weight, WeightMeter};

// The weight is limited to (10, 0).
let mut meter = WeightMeter::from_limit(Weight::from_parts(10, 0));
// There is enough weight remaining for an operation with (5, 0) weight.
assert!(meter.check_accrue(Weight::from_parts(5, 0)));
// There is not enough weight remaining for an operation with (6, 0) weight.
assert!(!meter.check_accrue(Weight::from_parts(6, 0)));

### Add starts_with to v0 and v1 MultiLocation
PR: https://github.com/paritytech/polkadot/pull/6311

Now `starts_with` is available to be used with `MultiLocation` type for v0 and v1. This function will return whether `self` begins with or is equal to a given `prefix`.

Signature of the function:

pub fn starts_with(&self, prefix: &Junctions) -> bool

This allows users to write checks like the following:

let full: MultiLocation = (Parent, Parachain(1000), AccountId32 { network: Any, id: [0; 32] }).into();
let identity: MultiLocation = full.clone();
let prefix: MultiLocation = (Parent, Parachain(1000)).into();
let wrong_parachain: MultiLocation = (Parent, Parachain(1001)).into();
let wrong_account: MultiLocation = (Parent, Parachain(1000), AccountId32 { network: Any, id: [1; 32] }).into();
let no_parents: MultiLocation = (Parachain(1000)).into();
let too_many_parents: MultiLocation = (Parent, Parent, Parachain(1000)).into();

assert!(full.starts_with(&identity));
assert!(full.starts_with(&prefix));
assert!(!full.starts_with(&wrong_parachain));
assert!(!full.starts_with(&wrong_account));
assert!(!full.starts_with(&no_parents));
assert!(!full.starts_with(&too_many_parents));

### Add Weightless benchmark bailing
PR: https://github.com/paritytech/substrate/pull/12829

*Polkadot Companion PR: [PR #6328](https://github.com/paritytech/polkadot/pull/6328)*

*Cumulus Companion PR: [PR #1940](https://github.com/paritytech/cumulus/pull/1940)*

**Why is this change interesting for builders?**

At the momemt, it's hard to write benchmarking if you have configured custom origin as `NeverEnsureOrigin` and you expect it be as dispatch origin.

You may need to add multiple `if`'s to handle such scenarios like [#11562](https://github.com/paritytech/substrate/pull/11562).

As a part of this PR, a new benchmarking error `Weightless` has been introduced, which indicates that no weight can be determined.

**How to use**

let custom_origin = T::CustomOrigin::try_successful_origin().map_err(|_| BenchmarkError::Weightless)?;

### Bounties use SpendOrigin
PR: https://github.com/paritytech/substrate/pull/12808

**Why is this change interesting for builders?**

[Bounties](https://paritytech.github.io/substrate/master/pallet_bounties/pallet/struct.Pallet.html) pallet uses `ApproveOrigin` for some dispatchable functions like `approve_bounty` and `propose_curator`. `ApproveOrigin` is the origin from where only approval comes. It does not have the information about how much the maximum amount that this origin is allowed to spend at a time.

After this PR, Bounties pallet will use `SpendOrigin` which solves this purpose. This will also be beneficial for OpenGov.

### contracts: Replace cargo feature unstable-interface with config
PR: https://github.com/paritytech/substrate/pull/12787

*Polkadot Companion PR: [PR #1916](https://github.com/paritytech/cumulus/pull/1916)*

**Why is this change interesting for builders?**

At the moment, if we want to access [Contracts](https://paritytech.github.io/substrate/master/pallet_contracts/index.html) pallet callable functions, which are marked with `#[unstable]`, we have to compile this with a substrate runtime feature `contracts-unstable-interface` using below command.

cargo run --release --features contracts-unstable-interface -- --dev

As part of this PR, this feature has been removed and a new config `UnsafeUnstableInterface` has been added in [Contracts](https://paritytech.github.io/substrate/master/pallet_contracts/index.html) pallet.

**How this impacts Polkadot builders?**

If you are using Contracts pallet in your runtime, you have to add this new config type, otherwise runtime compilation will fail because of a missing type error.

**How to use**

impl pallet_contracts::Config for Runtime {
	// Other Config types
	type UnsafeUnstableInterface = ConstBool<false>;
}

### MMR: move RPC code from frame/ to client/
PR: https://github.com/paritytech/substrate/pull/12805

*Polkadot Companion PR: [PR #6369](https://github.com/paritytech/cumulus/pull/6369)*

*Cumulus Companion PR: [PR #1923](https://github.com/paritytech/cumulus/pull/1923)*

**Why is this change interesting for builders?**

[Merkle Mountain Ranges(MMR)](https://github.com/mimblewimble/grin/blob/master/doc/mmr.md) are an alternative to Merkle trees. Before this PR, MMR RPC crate existed in Frame. As a part of this PR, this has been moved to the right place, which is in `client/`.

**How this impacts Polkadot builders?**

If you are using this crate, you may need to rename this crate in your codebase. Please see companion PRs for reference.

### Remove Default, HasCompact, and TypeInfo trait bounds on AssetId
PR: https://github.com/paritytech/substrate/pull/12740

*Cumulus Companion PR: [PR #1898](https://github.com/paritytech/cumulus/pull/1898)*

This PR is the part of [#Issue 12738](https://github.com/paritytech/substrate/issues/12738).

**Why is this change interesting for builders?**

If you are using [Assets](https://paritytech.github.io/substrate/master/pallet_assets/index.html) pallet for dealing with fungible assets and you want to use it's associated type `AssetId` to support those assets, your asset should meet the trait bound of `AssetId`.

As a part of this PR, the trait bound on `AssetId` has been relaxed.

**How this impacts Polkadot builders?**

In this PR, some trait bounds `Default`, `HasCompact`, and `TypeInfo` has been removed. This would cause the breaking changes at the existing places, where we are using `#[pallet::compact] id: T::AssetId` (compact asset id).

To prevent this breaking change, a new config type `AssetIdParameter` has also been introduced as a part of this PR.

A benchmarking helper trait `BenchmarkHelper` is also introduced to support the benchmarking of this new type.

**How to use**

If you are using Asset pallet in your runtime, you have to add these new config types, otherwise runtime compilation will fail because of missing type error.

impl pallet_assets::Config for Runtime {
    // Other Config types
    type AssetIdParameter = codec::Compact<u32>;
    #[cfg(feature = "runtime-benchmarks")]
    type BenchmarkHelper = ();
}

### add EnsureWithSuccess
PR: https://github.com/paritytech/substrate/pull/12775

**Why is this change interesting for builders?**

A new origin validator `EnsureWithSuccess` has been introduced as a part of this PR, which not only verifies the origin but also provides a success value.

Suppose we have a scenario, where we want to use some funds from an ensured origin. We can use `EnsureWithSuccess` in such scenarios. We can provide origins with some spend limit.

### Non-Interactive Staking
PR: https://github.com/paritytech/substrate/pull/12610

*Polkadot Companion PR: [PR #6352](https://github.com/paritytech/polkadot/pull/6352)*

**Why is this important?**

Gilt pallet is being renamed to Non-Interactive Staking (NIS) pallet with several updates to the pallet itself. NIS pallet (formerly known as Gilt pallet) allows for accounts to auction for being frozen and receive open-ended inflation-protection in return. Learn about the pallet [here](https://paritytech.github.io/substrate/master/pallet_nis/index.html).

Refer to the PR for a list of all the changes.

**How this impacts Polkadot builders?**

If you are using Gilt pallet in your runtime, you will have to modify your codebase to match the new name and modified associated types. If these changes are not made, runtime compilation will fail.

**How to use**

It is recommended to check the PR to see all the differences.
Let's take an example of updating a `runtime`:

In `Cargo.toml`, you have to replace `pallet-gilt` with `pallet-nis`.

Additionally, in `lib.rs` you will have to do similar,

- impl pallet_gilt::Config for Runtime {
+ impl pallet_nis::Config for Runtime {

// Modify the associated types

}

construct_runtime!(
    ....
-        Gilt: pallet_gilt,
+        Nis: pallet_nis,
    ....
    }
);