cc @joepetrowski

Westend now successfully updated to `spec: 103000`, we **have to
remove** the session keys migration before the next release as it
doesn't gracefully handle reapplying it.

Refunding surplus happens anyway on xcm_executor::post_process(),
automatically refunding surplus to original_origin at the end of
execution. Since SovereignPaidRemoteExporter doesn't ClearOrigin, it can
simply rely on the automatic mechanism.

Furthermore, RefundSurplus instruction refunds _surplus_. Surplus exists
only as a result of Transact, SetErrorHandler or SetAppendix
instructions, none of which being part of the
SovereignPaidRemoteExporter XCM program. So surplus is always zero here
anyway.

The goal of this PR is to migrate Identity deposits from the Relay Chain
to a system parachain.

The problem I want to solve is that `IdentityOf` and `SubsOf` both store
an amount that's held in reserve as a storage deposit. When migrating to
a parachain, we can take a snapshot of the actual `IdentityInfo` and
sub-account mappings, but should migrate (off chain) the `deposit`s to
zero, since the chain (and by extension, accounts) won't have any funds
at genesis.

The good news is that we expect parachain deposits to be significantly
lower (possibly 100x) on the parachain. That is, a deposit of 21 DOT on
the Relay Chain would need 0.21 DOT on a parachain. This PR proposes to
migrate the deposits in the following way:

1. Introduces a new pallet with two extrinsics: 
- `reap_identity`: Has a configurable `ReapOrigin`, which would be set
to `EnsureSigned` on the Relay Chain (i.e. callable by anyone) and
`EnsureRoot` on the parachain (we don't want identities reaped from
there).
- `poke_deposit`: Checks what deposit the pallet holds (at genesis,
zero) and attempts to update the amount based on the calculated deposit
for storage data.
2. `reap_identity` clears all storage data for a `target` account and
unreserves their deposit.
3. A `ReapIdentityHandler` teleports the necessary DOT to the parachain
and calls `poke_deposit`. Since the parachain deposit is much lower, and
was just unreserved, we know we have enough.

One awkwardness I ran into was that the XCMv3 instruction set does not
provide a way for the system to teleport assets without a fee being
deducted on reception. Users shouldn't have to pay a fee for the system
to migrate their info to a more efficient location. So I wrote my own
program and did the `InitiateTeleport` accounting on my own to send a
program with `UnpaidExecution`. Have discussed an
`InitiateUnpaidTeleport` instruction with @franciscoaguirre

 . Obviously
any chain executing this would have to pass a `Barrier` for free
execution.

TODO:

- [x] Confirm People Chain ParaId
- [x] Confirm People Chain deposit rates (determined in
https://github.com/paritytech/polkadot-sdk/pull/2281)
- [x] Add pallet to Westend

---------

Co-authored-by: Bastian Köcher <[email protected]>

Disallow reserve transfers that use teleportable fees if `(origin,
fees)` matches `XcmTeleportFilter`.

Add regression tests for filtering based on `XcmTeleportFilter` for both
`(limited_)reserve_transfer_assets()` and `(limited_)teleport_assets`
extrinsics.

This PR introduces:
- XCM  host functions `xcm_send`, `xcm_execute`
- An Xcm trait into the config. that proxy these functions to to
`pallet_xcm`, or disable their usage by using `()`.
- A mock_network and xcm_test files to test the newly added xcm-related
functions.

---------

Co-authored-by: Keith Yeung <[email protected]>
Co-authored-by: Sasha Gryaznov <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: Alexander Theißen <[email protected]>

Adds a `NodeFeatures` bitfield value to the runtime `HostConfiguration`,
with the purpose of coordinating the enabling of node-side features,
such as: https://github.com/paritytech/polkadot-sdk/issues/628 and
https://github.com/paritytech/polkadot-sdk/issues/598.
These are features that require all validators enable them at the same
time, assuming all/most nodes have upgraded their node versions.

This PR doesn't add any feature yet. These are coming in future PRs.

Also adds a runtime API for querying the state of the client features
and an extrinsic for setting/unsetting a feature by its index in the bitfield.

Note: originally part of:
https://github.com/paritytech/polkadot-sdk/pull/1644, but posted as
standalone to be reused by other PRs until the initial PR is merged

Fixes #1437

Co-authored-by: Sophia Gold <[email protected]>

Co-authored-by: Marcin S <[email protected]>

## Problem/Motivation
The benchmark for the `ExpectPallet` XCM instruction uses a hard-coded
version `4.0.0` for the `frame_system` pallet. Unfortunately, this
doesn't work for the `polkadot-fellows/runtimes` repository, where we
use dependencies from `crates.io`, e.g.,
[frame-system::23.0.0.0](https://github.com/polkadot-fellows/runtimes/blob/dd7f86f0d50064481ed0b7c0218494a5cfad997e/relay/kusama/Cargo.toml#L83).

Closes: https://github.com/paritytech/polkadot-sdk/issues/2284 

## Solution
This PR fixes the benchmarks that require pallet information and enables
the runtime to provide the correct/custom pallet information. The
default implementation provides `frame_system::Pallet` with index `0`,
where the version is not hard-coded but read from the runtime.


## Local testing

Added log for `T::valid_pallet` to the benchmarks like:
```
let valid_pallet = T::valid_pallet();
log::info!(
	target: "frame::benchmark::pallet",
	"valid_pallet: {}::{}::{}::{}::{}",
	valid_pallet.index,
	valid_pallet.module_name,
	valid_pallet.crate_version.major,
	valid_pallet.crate_version.minor,
	valid_pallet.crate_version.patch,
);
```

Run benchmarks for `westend`:
```
cargo run --bin=polkadot --features=runtime-benchmarks -- benchmark pallet --steps=2 --repeat=1 --extrinsic=* --heap-pages=4096 --json-file=./bench.json --chain=westend-dev --template=./polkadot/xcm/pallet-xcm-benchmarks/template.hbs --pallet=pallet_xcm_benchmarks::generic --output=./polkadot/runtime/westend/src/weights/xcm
```

---

For actual `frame_system` version:
```
[package]
name = "frame-system"
version = "4.0.0-dev"
```

Log dump:
```
2023-11-13 12:56:45 Starting benchmark: pallet_xcm_benchmarks::generic::query_pallet    
2023-11-13 12:56:45 valid_pallet: 0::frame_system::4::0::0    
2023-11-13 12:56:45 valid_pallet: 0::frame_system::4::0::0    
2023-11-13 12:56:45 valid_pallet: 0::frame_system::4::0::0    
2023-11-13 12:56:45 Starting benchmark: pallet_xcm_benchmarks::generic::expect_pallet    
2023-11-13 12:56:45 valid_pallet: 0::frame_system::4::0::0    
2023-11-13 12:56:45 valid_pallet: 0::frame_system::4::0::0    
2023-11-13 12:56:45 valid_pallet: 0::frame_system::4::0::0 
```


For changed `frame_system` version:
```
[package]
name = "frame-system"
version = "5.1.3-dev"
```

Log dump:
```
2023-11-13 12:51:51 Starting benchmark: pallet_xcm_benchmarks::generic::query_pallet    
2023-11-13 12:51:51 valid_pallet: 0::frame_system::5::1::3    
2023-11-13 12:51:51 valid_pallet: 0::frame_system::5::1::3    
2023-11-13 12:51:51 valid_pallet: 0::frame_system::5::1::3    
2023-11-13 12:51:51 Starting benchmark: pallet_xcm_benchmarks::generic::expect_pallet    
2023-11-13 12:51:51 valid_pallet: 0::frame_system::5::1::3    
2023-11-13 12:51:51 valid_pallet: 0::frame_system::5::1::3    
2023-11-13 12:51:51 valid_pallet: 0::frame_system::5::1::3
```

## References

Closes: https://github.com/paritytech/polkadot-sdk/issues/2284

Collators were previously reencoding the available data and checking the
erasure root.
Replace that with just checking the PoV hash, which consumes much less
CPU and takes less time.

We also don't need to check the `PersistedValidationData` hash, as
collators don't use it.

Reason:
https://github.com/paritytech/polkadot-sdk/issues/575#issuecomment-1806572230

After systematic chunks recovery is merged, collators will no longer do
any reed-solomon encoding/decoding, which has proven to be a great CPU
consumer.

Signed-off-by: alindima <[email protected]>

## Motivation

`pallet-xcm` is the main user-facing interface for XCM functionality,
including assets manipulation functions like `teleportAssets()` and
`reserve_transfer_assets()` calls.

While `teleportAsset()` works both ways, `reserve_transfer_assets()`
works only for sending reserve-based assets to a remote destination and
beneficiary when the reserve is the _local chain_.

## Solution

This PR enhances `pallet_xcm::(limited_)reserve_withdraw_assets` to
support transfers when reserves are other chains.
This will allow complete, **bi-directional** reserve-based asset
transfers user stories using `pallet-xcm`.

Enables following scenarios:
- transferring assets with local reserve (was previously supported iff
asset used as fee also had local reserve - now it works in all cases),
- transferring assets with reserve on destination,
- transferring assets with reserve on remote/third-party chain (iff
assets and fees have same remote reserve),
- transferring assets with reserve different than the reserve of the
asset to be used as fees - meaning can be used to transfer random asset
with local/dest reserve while using DOT for fees on all involved chains,
even if DOT local/dest reserve doesn't match asset reserve,
- transferring assets with any type of local/dest reserve while using
fees which can be teleported between involved chains.

All of the above is done by pallet inner logic without the user having
to specify which scenario/reserves/teleports/etc. The correct scenario
and corresponding XCM programs are identified, and respectively, built
automatically based on runtime configuration of trusted teleporters and
trusted reserves.

#### Current limitations:
- while `fees` and "non-fee" `assets` CAN have different reserves (or
fees CAN be teleported), the remaining "non-fee" `assets` CANNOT, among
themselves, have different reserve locations (this is also implicitly
enforced by `MAX_ASSETS_FOR_TRANSFER=2`, but this can be safely
increased in the future).
- `fees` and "non-fee" `assets` CANNOT have **different remote**
reserves (this could also be supported in the future, but adds even more
complexity while possibly not being worth it - we'll see what the future
holds).

Fixes https://github.com/paritytech/polkadot-sdk/issues/1584
Fixes https://github.com/paritytech/polkadot-sdk/issues/2055

---------

Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>

Remove the `GRANDPA_AUTHORITIES_KEY` key and its usage. Apparently this
was used in the early days to communicate the grandpa authorities to the
node. However, we have now a runtime api that does this for us. So, this
pull request is moving from the custom managed storage item to a FRAME
managed storage item.

This pr also includes a migration for doing the switch on a running
chain.

---------

Co-authored-by: Davide Galassi <[email protected]>

Co-authored-by: Bastian Köcher <[email protected]>

We are introducing a new set of `XcmController` traits (final name yet
to be determined).
These traits are implemented by `pallet-xcm` and allows other pallets,
such as `pallet_contracts`, to rely on these traits instead of tight
coupling them to `pallet-xcm`.

Using only the existing Xcm traits would mean duplicating the logic from
`pallet-xcm` in these other pallets, which we aim to avoid. Our
objective is to ensure that when these APIs are called from
`pallet-contracts`, they produce the exact same outcomes as if called
directly from `pallet-xcm`.

The other benefits is that we can also expose return values to
`pallet-contracts` instead of just calling `pallet-xcm` dispatchable and
getting a `DispatchResult` back.

See traits integration in this PR
https://github.com/paritytech/polkadot-sdk/pull/1248, where the traits
are used as follow to define and implement `pallet-contracts` Config.
```rs
// Contracts config:
pub trait Config: frame_system::Config {
  // ...

  /// A type that exposes XCM APIs, allowing contracts to interact with other parachains, and
  /// execute XCM programs.
  type Xcm: xcm_executor::traits::Controller<
	  OriginFor<Self>,
	  <Self as frame_system::Config>::RuntimeCall,
	  BlockNumberFor<Self>,
  >;
}

// implementation
impl pallet_contracts::Config for Runtime {
        // ...

	type Xcm = pallet_xcm::Pallet<Self>;
}
```

---------

Co-authored-by: Alexander Theißen <[email protected]>
Co-authored-by: command-bot <>

As suggested by @ggwpez
(https://github.com/paritytech/polkadot-sdk/pull/2142#discussion_r1388145872),
remove the `VersionChecked` prefix from version checked migrations (but
leave `VersionUnchecked` prefixes)

---------

Co-authored-by: command-bot <>

The staging- rename commit was missing from the last PR for some reason.

Missing descriptions (47):  

- [x] `cumulus/client/collator/Cargo.toml`
- [x] `cumulus/client/relay-chain-inprocess-interface/Cargo.toml`
- [x] `cumulus/client/cli/Cargo.toml`
- [x] `cumulus/client/service/Cargo.toml`
- [x] `cumulus/client/relay-chain-rpc-interface/Cargo.toml`
- [x] `cumulus/client/relay-chain-interface/Cargo.toml`
- [x] `cumulus/client/relay-chain-minimal-node/Cargo.toml`
- [x] `cumulus/parachains/pallets/parachain-info/Cargo.toml`
- [x] `cumulus/parachains/pallets/ping/Cargo.toml`
- [x] `cumulus/primitives/utility/Cargo.toml`
- [x] `cumulus/primitives/aura/Cargo.toml`
- [x] `cumulus/primitives/core/Cargo.toml`
- [x] `cumulus/primitives/parachain-inherent/Cargo.toml`
- [x] `cumulus/test/relay-sproof-builder/Cargo.toml`
- [x] `cumulus/pallets/xcmp-queue/Cargo.toml`
- [x] `cumulus/pallets/dmp-queue/Cargo.toml`
- [x] `cumulus/pallets/xcm/Cargo.toml`
- [x] `polkadot/erasure-coding/Cargo.toml`
- [x] `polkadot/statement-table/Cargo.toml`
- [x] `polkadot/primitives/Cargo.toml`
- [x] `polkadot/rpc/Cargo.toml`
- [x] `polkadot/node/service/Cargo.toml`
- [x] `polkadot/node/core/parachains-inherent/Cargo.toml`
- [x] `polkadot/node/core/approval-voting/Cargo.toml`
- [x] `polkadot/node/core/dispute-coordinator/Cargo.toml`
- [x] `polkadot/node/core/av-store/Cargo.toml`
- [x] `polkadot/node/core/chain-api/Cargo.toml`
- [x] `polkadot/node/core/prospective-parachains/Cargo.toml`
- [x] `polkadot/node/core/backing/Cargo.toml`
- [x] `polkadot/node/core/provisioner/Cargo.toml`
- [x] `polkadot/node/core/runtime-api/Cargo.toml`
- [x] `polkadot/node/core/bitfield-signing/Cargo.toml`
- [x] `polkadot/node/network/dispute-distribution/Cargo.toml`
- [x] `polkadot/node/network/bridge/Cargo.toml`
- [x] `polkadot/node/network/collator-protocol/Cargo.toml`
- [x] `polkadot/node/network/approval-distribution/Cargo.toml`
- [x] `polkadot/node/network/availability-distribution/Cargo.toml`
- [x] `polkadot/node/network/bitfield-distribution/Cargo.toml`
- [x] `polkadot/node/network/gossip-support/Cargo.toml`
- [x] `polkadot/node/network/availability-recovery/Cargo.toml`
- [x] `polkadot/node/collation-generation/Cargo.toml`
- [x] `polkadot/node/overseer/Cargo.toml`
- [x] `polkadot/runtime/parachains/Cargo.toml`
- [x] `polkadot/runtime/common/slot_range_helper/Cargo.toml`
- [x] `polkadot/runtime/metrics/Cargo.toml`
- [x] `polkadot/xcm/pallet-xcm-benchmarks/Cargo.toml`
- [x] `polkadot/utils/generate-bags/Cargo.toml`
- [x]  `substrate/bin/minimal/runtime/Cargo.toml`

---------

Signed-off-by: Oliver Tale-Yazdi <[email protected]>
Signed-off-by: alindima <[email protected]>
Co-authored-by: ordian <[email protected]>
Co-authored-by: Tsvetomir Dimitrov <[email protected]>
Co-authored-by: Marcin S <[email protected]>
Co-authored-by: alindima <[email protected]>
Co-authored-by: Sebastian Kunert <[email protected]>
Co-authored-by: Dmitry Markin <[email protected]>
Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: Liam Aharon <[email protected]>

This was discovered during a debugging session, and it only served to
mask the underlying error, which was not great.

One for local networks with `fast-runtime` feature activated (1 minute
sessions) and one without the feature activated that will be the default
that runs with 1 hour long sessions.

PalletInfo fields were private, preventing a user from actually using
the QueryPallet instruction in a meaningful way since they couldn't read
the received data.

Changes:
- Adds a new call `remove_key` to the sudo pallet to permanently remove
the sudo key.
- Remove some clones and general maintenance

---------

Signed-off-by: Oliver Tale-Yazdi <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: command-bot <>

Added a proc macro to be able to write XCMs using the builder pattern.
This means we go from having to do this:

```rust
let message: Xcm<()> = Xcm(vec![
  WithdrawAsset(assets),
  BuyExecution { fees: asset, weight_limit: Unlimited },
  DepositAsset { assets, beneficiary },
]);
```

to this:

```rust
let message: Xcm<()> = Xcm::builder()
  .withdraw_asset(assets)
  .buy_execution(asset, Unlimited),
  .deposit_asset(assets, beneficiary)
  .build();
```

---------

Co-authored-by: Keith Yeung <[email protected]>
Co-authored-by: command-bot <>

Part of #2186

The only usage of pallet-asset-rate is guarded by `runtime-benchmarks`
feature. I don't want ORML to be forced to include this pallet in deps
for no good reason.

There was a race in merging between
https://github.com/paritytech/polkadot-sdk/pull/1256 and
https://github.com/paritytech/polkadot-sdk/pull/1178, so this newly
added tests wasn't updated with the new path for the configuration, so
fix that.

Signed-off-by: Alexandru Gheorghe <[email protected]>

availability-distribution subsystem is not sending availability-recovery
messages. Update the overseer declaration to reflect this

**_PR migrated from https://github.com/paritytech/polkadot/pull/6782_** 

This PR will upgrade the network protocol to version 3 -> VStaging which
will later be renamed to V3. This version introduces a new kind of
assignment certificate that will be used for tranche0 assignments.
Instead of issuing/importing one tranche0 assignment per candidate,
there will be just one certificate per relay chain block per validator.
However, we will not be sending out the new assignment certificates,
yet. So everything should work exactly as before. Once the majority of
the validators have been upgraded to the new protocol version we will
enable the new certificates (starting at a specific relay chain block)
with a new client update.

There are still a few things that need to be done:

- [x] Use bitfield instead of Vec<CandidateIndex>:
https://github.com/paritytech/polkadot/pull/6802
  - [x] Fix existing approval-distribution and approval-voting tests
  - [x] Fix bitfield-distribution and statement-distribution tests
  - [x] Fix network bridge tests
  - [x] Implement todos in the code
  - [x] Add tests to cover new code
  - [x] Update metrics
  - [x] Remove the approval distribution aggression levels: TBD PR
  - [x] Parachains DB migration 
  - [x] Test network protocol upgrade on Versi
  - [x] Versi Load test
  - [x] Add Zombienet test
  - [x] Documentation updates
- [x] Fix for sending DistributeAssignment for each candidate claimed by
a v2 assignment (warning: Importing locally an already known assignment)
 - [x]  Fix AcceptedDuplicate
 - [x] Fix DB migration so that we can still keep old data.
 - [x] Final Versi burn in

---------

Signed-off-by: Andrei Sandu <[email protected]>
Signed-off-by: Alexandru Gheorghe <[email protected]>
Co-authored-by: Alexandru Gheorghe <[email protected]>

This PR exposes a `force_remove_vesting` through a ROOT call. 
See linked
[issue](https://github.com/paritytech/polkadot-sdk/issues/269)

---------

Co-authored-by: georgepisaltu <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: Dónal Murray <[email protected]>

... see https://github.com/paritytech/polkadot-sdk/issues/2138 for why
is not good, until we fix it let's add a warning to understand if this
is happening in the wild.

---------

Signed-off-by: Alexandru Gheorghe <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>

This PR updates the version of `serde_json` to `1.0.108` throughout the
codebase.

This PR prepares chains specs for _native-runtime-free_  world.

This PR has following changes:
- `substrate`:
  - adds support for:
- JSON based `GenesisConfig` to `ChainSpec` allowing interaction with
runtime `GenesisBuilder` API.
- interacting with arbitrary runtime wasm blob to[
`chain-spec-builder`](https://github.com/paritytech/substrate/blob/3ef576eaeb3f42610e85daecc464961cf1295570/bin/utils/chain-spec-builder/src/lib.rs#L46)
command line util,
- removes
[`code`](https://github.com/paritytech/substrate/blob/3ef576eaeb3f42610e85daecc464961cf1295570/frame/system/src/lib.rs#L660)
from `system_pallet`
  - adds `code` to the `ChainSpec`
- deprecates
[`ChainSpec::from_genesis`](https://github.com/paritytech/substrate/blob/3ef576eaeb3f42610e85daecc464961cf1295570/client/chain-spec/src/chain_spec.rs#L263),
but also changes the signature of this method extending it with `code`
argument.
[`ChainSpec::builder()`](https://github.com/paritytech/substrate/blob/20bee680ed098be7239cf7a6b804cd4de267983e/client/chain-spec/src/chain_spec.rs#L507)
should be used instead.
- `polkadot`:
- all references to `RuntimeGenesisConfig` in `node/service` are
removed,
- all
`(kusama|polkadot|versi|rococo|wococo)_(staging|dev)_genesis_config`
functions now return the JSON patch for default runtime `GenesisConfig`,
  - `ChainSpecBuilder` is used, `ChainSpec::from_genesis` is removed,

- `cumulus`:
  - `ChainSpecBuilder` is used, `ChainSpec::from_genesis` is removed,
- _JSON_ patch configuration used instead of `RuntimeGenesisConfig
struct` in all chain specs.
  
---------

Co-authored-by: command-bot <>
Co-authored-by: Javier Viola <[email protected]>
Co-authored-by: Davide Galassi <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: Kevin Krone <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>

# Description

Update the bootnode of kusama parachains before decommissioning the
nodes. This will avoid connecting to non-existing bootnodes.

This PR is a follow up to #1661 

- [x] rename the `simple` module to `legacy`
- [x] fix benchmarks to disregard the number of additional fields
- [x] change the storage deposits to charge per encoded byte of the
identity information instance, removing the need for `fn
additional(&self) -> usize` in `IdentityInformationProvider`
- [x] ~add an extrinsic to rejig deposits to account for the change
above~
- [ ] ~ensure through proper configuration that the new byte-based
deposit is always lower than whatever is reserved now~
- [x] remove `IdentityFields` from the `set_fields` extrinsic signature,
as per [this
discussion](https://github.com/paritytech/polkadot-sdk/pull/1661#discussion_r1371703403)

> ensure through proper configuration that the new byte-based deposit is
always lower than whatever is reserved now

Not sure this is needed anymore. If the new deposits are higher than
what is currently on chain and users don't have enough funds to reserve
what is needed, the extrinisc fails and they're basically grandfathered
and frozen until they add more funds and/or make a change to their
identity. This behavior seems fine to me. Original idea
[here](https://github.com/paritytech/polkadot-sdk/pull/1661#issuecomment-1779606319).

> add an extrinsic to rejig deposits to account for the change above

This was initially implemented but now removed from this PR in favor of
the implementation detailed
[here](https://github.com/paritytech/polkadot-sdk/pull/2088).

---------

Signed-off-by: georgepisaltu <[email protected]>
Co-authored-by: joepetrowski <[email protected]>

The `BlockBuilderProvider` was a trait that was defined in
`sc-block-builder`. The trait was implemented for `Client`. This
basically meant that you needed to import `sc-block-builder` any way to
have access to the block builder. So, this trait was not providing any
real value. This pull request is removing the said trait. Instead of the
trait it introduces a builder for creating a `BlockBuilder`. The builder
currently has the quite fabulous name `BlockBuilderBuilder` (I'm open to
any better name 😅

). The rest of the pull request is about
replacing the old trait with the new builder.

# Downstream code changes

If you used `new_block` or `new_block_at` before you now need to switch
it over to the new `BlockBuilderBuilder` pattern:

```rust
// `new` requires a type that implements `CallApiAt`. 
let mut block_builder = BlockBuilderBuilder::new(client)
                // Then you need to specify the hash of the parent block the block will be build on top of
		.on_parent_block(at)
                // The block builder also needs the block number of the parent block. 
                // Here it is fetched from the given `client` using the `HeaderBackend`
                // However, there also exists `with_parent_block_number` for directly passing the number
		.fetch_parent_block_number(client)
		.unwrap()
                // Enable proof recording if required. This call is optional.
		.enable_proof_recording()
                // Pass the digests. This call is optional.
                .with_inherent_digests(digests)
		.build()
		.expect("Creates new block builder");
```

---------

Co-authored-by: Sebastian Kunert <[email protected]>
Co-authored-by: command-bot <>