This PR backports version bumps from `1.7.0` release branch and moves
related prdoc files to the appropriate folder.

Relates to: https://github.com/paritytech/polkadot-sdk/issues/3214

## TODO

- [ ] backport to the `1.7.0` release

Removes the `bridges/snowbridge/parachain` directory and moves
everything up to under `snowbridge` directly. We are cleaning up our
local dev env after merging our crates into the polkadot-sdk.

---------

Co-authored-by: claravanstaden <Cats 4 life!>

Built on top of https://github.com/paritytech/polkadot-sdk/pull/2826/
which was a trial run.

Guide:
https://github.com/w3f/polkadot-wiki/blob/master/docs/maintain/maintain-guides-async-backing.md

---------

Signed-off-by: georgepisaltu <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Dónal Murray <[email protected]>
Co-authored-by: Dmitry Sinyavin <[email protected]>
Co-authored-by: s0me0ne-unkn0wn <[email protected]>
Co-authored-by: Svyatoslav Nikolsky <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: georgepisaltu <[email protected]>

## TODO
- [x] change constants when CI fails (should fail :) )

## Result

On the AssetHubRococo: 1701175800126 -> 1700929825257 = 0.15 %
decreased.
```
# Before ( [xcm] Fix `SovereignPaidRemoteExporter` and `DepositAsset` handling (#3157))
Feb 02 12:59:05.520 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 1701175800126 for runtime: statemine-1006000 (statemine-0.tx14.au1)    

# After
Feb 02 13:02:40.647 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 1700929825257 for runtime: statemine-1006000 (statemine-0.tx14.au1)    

```

On the AssetHubWestend: 2116038876326 -> 1641718372993 = 22.4 %
decreased.
```
# Before ( [xcm] Fix `SovereignPaidRemoteExporter` and `DepositAsset` handling (#3157))
Feb 02 12:56:00.880 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 2116038876326 for runtime: westmint-1006000 (westmint-0.tx14.au1)    


# After
Feb 02 13:04:42.515 ERROR bridges::estimate: `bridging::XcmBridgeHubRouterBaseFee` actual value: 1641718372993 for runtime: westmint-1006000 (westmint-0.tx14.au1)    
```

This PR addresses two issues:
- It modifies `DepositAsset`'s asset filter from `All` to
`AllCounted(1)` to prevent potentially charging excessive weight/fees.
This adjustment avoids situations where fees could be calculated based
on the count of assets, as illustrated
[here](https://github.com/paritytech/polkadot-sdk/blob/master/cumulus/parachains/runtimes/bridge-hubs/bridge-hub-rococo/src/weights/xcm/mod.rs#L38-L46).
- It encapsulates `DepositAsset` with `SetAppendix` to ensure that
`fees` are not trapped in any case. For instance, this prevents issues
when `ExportXcm::validate` encounters an error during the processing of
`ExportMessage`.

[frame] `#[pallet::composite_enum]` improved variant count handling + removed `pallet_balances`'s `MaxHolds` config (#2657)

I started this investigation/issue based on @liamaharon

 question
[here](https://github.com/paritytech/polkadot-sdk/pull/1801#discussion_r1410452499).

## Problem

The `pallet_balances` integrity test should correctly detect that the
runtime has correct distinct `HoldReasons` variant count. I assume the
same situation exists for RuntimeFreezeReason.

It is not a critical problem, if we set `MaxHolds` with a sufficiently
large value, everything should be ok. However, in this case, the
integrity_test check becomes less useful.

**Situation for "any" runtime:**
- `HoldReason` enums from different pallets:
```rust
        /// from pallet_nis
        #[pallet::composite_enum]
	pub enum HoldReason {
		NftReceipt,
	}

        /// from pallet_preimage
        #[pallet::composite_enum]
	pub enum HoldReason {
		Preimage,
	}

        // from pallet_state-trie-migration
        #[pallet::composite_enum]
	pub enum HoldReason {
		SlashForContinueMigrate,
		SlashForMigrateCustomTop,
		SlashForMigrateCustomChild,
	}
```

- generated `RuntimeHoldReason` enum looks like:
```rust
pub enum RuntimeHoldReason {

    #[codec(index = 32u8)]
    Preimage(pallet_preimage::HoldReason),

    #[codec(index = 38u8)]
    Nis(pallet_nis::HoldReason),

    #[codec(index = 42u8)]
    StateTrieMigration(pallet_state_trie_migration::HoldReason),
}
```

- composite enum `RuntimeHoldReason` variant count is detected as `3`
- we set `type MaxHolds = ConstU32<3>`
- `pallet_balances::integrity_test` is ok with `3`(at least 3)

However, the real problem can occur in a live runtime where some
functionality might stop working. This is due to a total of 5 distinct
hold reasons (for pallets with multi-instance support, it is even more),
and not all of them can be used because of an incorrect `MaxHolds`,
which is deemed acceptable according to the `integrity_test`:
  ```
  // pseudo-code - if we try to call all of these:

T::Currency::hold(&pallet_nis::HoldReason::NftReceipt.into(),
&nft_owner, deposit)?;
T::Currency::hold(&pallet_preimage::HoldReason::Preimage.into(),
&nft_owner, deposit)?;

T::Currency::hold(&pallet_state_trie_migration::HoldReason::SlashForContinueMigrate.into(),
&nft_owner, deposit)?;

  // With `type MaxHolds = ConstU32<3>` these two will fail

T::Currency::hold(&pallet_state_trie_migration::HoldReason::SlashForMigrateCustomTop.into(),
&nft_owner, deposit)?;

T::Currency::hold(&pallet_state_trie_migration::HoldReason::SlashForMigrateCustomChild.into(),
&nft_owner, deposit)?;
  ```  


## Solutions

A macro `#[pallet::*]` expansion is extended of `VariantCount`
implementation for the `#[pallet::composite_enum]` enum type. This
expansion generates the `VariantCount` implementation for pallets'
`HoldReason`, `FreezeReason`, `LockId`, and `SlashReason`. Enum variants
must be plain enum values without fields to ensure a deterministic
count.

The composite runtime enum, `RuntimeHoldReason` and
`RuntimeFreezeReason`, now sets `VariantCount::VARIANT_COUNT` as the sum
of pallets' enum `VariantCount::VARIANT_COUNT`:
```rust
#[frame_support::pallet(dev_mode)]
mod module_single_instance {

	#[pallet::composite_enum]
	pub enum HoldReason {
		ModuleSingleInstanceReason1,
		ModuleSingleInstanceReason2,
	}
...
}

#[frame_support::pallet(dev_mode)]
mod module_multi_instance {

	#[pallet::composite_enum]
	pub enum HoldReason<I: 'static = ()> {
		ModuleMultiInstanceReason1,
		ModuleMultiInstanceReason2,
		ModuleMultiInstanceReason3,
	}
...
}


impl self::sp_api_hidden_includes_construct_runtime::hidden_include::traits::VariantCount
    for RuntimeHoldReason
{
    const VARIANT_COUNT: u32 = 0
        + module_single_instance::HoldReason::VARIANT_COUNT
        + module_multi_instance::HoldReason::<module_multi_instance::Instance1>::VARIANT_COUNT
        + module_multi_instance::HoldReason::<module_multi_instance::Instance2>::VARIANT_COUNT
        + module_multi_instance::HoldReason::<module_multi_instance::Instance3>::VARIANT_COUNT;
}
```

In addition, `MaxHolds` is removed (as suggested
[here](https://github.com/paritytech/polkadot-sdk/pull/2657#discussion_r1443324573))
from `pallet_balances`, and its `Holds` are now bounded to
`RuntimeHoldReason::VARIANT_COUNT`. Therefore, there is no need to let
the runtime specify `MaxHolds`.


## For reviewers

Relevant changes can be found here:
- `substrate/frame/support/procedural/src/lib.rs` 
-  `substrate/frame/support/procedural/src/pallet/parse/composite.rs`
-  `substrate/frame/support/procedural/src/pallet/expand/composite.rs`
-
`substrate/frame/support/procedural/src/construct_runtime/expand/composite_helper.rs`
-
`substrate/frame/support/procedural/src/construct_runtime/expand/hold_reason.rs`
-
`substrate/frame/support/procedural/src/construct_runtime/expand/freeze_reason.rs`
- `substrate/frame/support/src/traits/misc.rs`

And the rest of the files is just about removed `MaxHolds` from
`pallet_balances`

## Next steps

Do the same for `MaxFreezes`
https://github.com/paritytech/polkadot-sdk/issues/2997.

---------

Co-authored-by: command-bot <>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: Dónal Murray <[email protected]>
Co-authored-by: gupnik <[email protected]>

The `parachains-common` contains a lots of constants and type
definitions which are used for `polkadot-sdk`'s testnet runtimes and
also for `polkadot-fellows`'s production [SP
runtimes](https://github.com/polkadot-fellows/runtimes/tree/main/system-parachains/constants).
This PR cleans `parachains-common` module to contain only common and
generic functionality.

Testnet-specific constants have been moved to the separate module
dedicated just for testnets:
`polkadot-sdk/cumulus/parachains/runtimes/constants/`


Part of: https://github.com/paritytech/polkadot-sdk/issues/3054

---------

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

Add `Balances::force_adjust_total_issuance` as preparation for fixing
https://github.com/polkadot-fellows/runtimes/issues/147.
Important changes in `substrate/frame/balances/src/lib.rs`.

TODO:
- [x] Update weights

---------

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

Reverts paritytech/polkadot-sdk#2302. 🤦‍♂️ should have checked the
migration CI first.

We either need to reduce the `max_message_size` for the open HRMP
channels on the failing chains or increase the `PageSize` of the XCMP
queue.
Both would be fine on a test-net, but i assume this will also fail
before the next SP runtime upgrade so first need to think what best to
do.
AFAIK its not possible currently to change the `max_message_size` of an
open HRMP channel.

Remove `without_storage_info` from the XCMP queue pallet. Part of
https://github.com/paritytech/polkadot-sdk/issues/323

Changes:
- Limit the number of channels that can be suspended at the same time.
- Limit the number of channels that can have messages or signals pending
at the same time.

A No-OP migration is put in place to ensure that all `BoundedVec`s still
decode and not truncate after upgrade. The storage version is thereby
bumped to 4 to have our tooling remind us to deploy that migration.

---------

Signed-off-by: Oliver Tale-Yazdi <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>

Related https://github.com/paritytech/polkadot-sdk/issues/3032

---

Using https://github.com/liamaharon/cargo-workspace-version-tools/ 

`cargo run -- sync --path ../polkadot-sdk`

---------

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

Moved from: https://github.com/paritytech/polkadot/pull/6951

closes https://github.com/paritytech/polkadot-sdk/issues/490

- [x] update cumulus

--- 
This PR introduces transactional processing of certain xcm instructions.
For the list of instructions checkout
https://github.com/paritytech/polkadot-sdk/issues/490. The transactional
processing is implemented as an xcm-executor config item. The two
implementations in this PR are `FrameTransactionalProcessor` and `()`.
The `()` implementation does no transactional processing. Each
implementation of the `ProcessTransaction` trait has an
`IS_TRANSACTIONAL` const that tells the XCVM if transactional processing
is actually implemented. If Transactional processing is implemented,
changes to touched registers should also be rolled back to prevent
inconsistencies.


Note for reviewers:
Check out the following safety assumption:
https://github.com/paritytech/polkadot-sdk/pull/1222/files#diff-4effad7d8c1c9de19fd27e18661cbf2128c8718f3b2420a27d2f816e0749ea53R30

---------

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

This PR avoids automatically pulling rococo/westend runtime constants
into the runtime by default. Usually, we have testnet runtimes dedicated
to rococo or westend, and therefore, we don't need both dependencies.
Additionally, it prevents pulling rococo/westend-related items into the
`polkadot-fellows` repo, as seen in the Cargo.lock
[here](https://github.com/polkadot-fellows/runtimes/blob/main/Cargo.lock#L14137-L14151)
and
[here](https://github.com/polkadot-fellows/runtimes/blob/main/Cargo.lock#L9756-L9770).

---------

Co-authored-by: Adrian Catangiu <[email protected]>

## Summary

This PR consolidates `pallet-state-trie-migration` as a part of
https://github.com/paritytech/polkadot-sdk/issues/226 /
https://github.com/paritytech/polkadot-sdk/issues/171:

`pallet-state-trie-migration`:
- [x] replace `Currency` with `fungible` traits
- [x] run benchmarks
- [x] refactor to `DefaultConfig`

`pallet_nicks`:
- [x]  remove

others:
- [x] remove `as Fn*` or `asFun*` stuff based on discussion
[here](https://github.com/paritytech/polkadot-sdk/issues/226#issuecomment-1822861445)

---------

Co-authored-by: Richard Melkonian <[email protected]>
Co-authored-by: command-bot <>

There were several improvements and PRs that didn't apply to all
runtimes, so this PR attempts to align those small differences. In
addition, the PR eliminates unused dependencies across multiple modules.

Relates to PR for `polkadot-fellows`:
https://github.com/polkadot-fellows/runtimes/pull/154

This is a rather big change in jsonrpsee, the major things in this bump
are:
- Server backpressure (the subscription impls are modified to deal with
that)
- Allow custom error types / return types (remove jsonrpsee::core::Error
and jsonrpee::core::CallError)
- Bug fixes (graceful shutdown in particular not used by substrate
anyway)
   - Less dependencies for the clients in particular
   - Return type requires Clone in method call responses
   - Moved to tokio channels
   - Async subscription API (not used in this PR)

Major changes in this PR:
- The subscriptions are now bounded and if subscription can't keep up
with the server it is dropped
- CLI: add parameter to configure the jsonrpc server bounded message
buffer (default is 64)
- Add our own subscription helper to deal with the unbounded streams in
substrate

The most important things in this PR to review is the added helpers
functions in `substrate/client/rpc/src/utils.rs` and the rest is pretty
much chore.

Regarding the "bounded buffer limit" it may cause the server to handle
the JSON-RPC calls
slower than before.

The message size limit is bounded by "--rpc-response-size" thus "by
default 10MB * 64 = 640MB"
but the subscription message size is not covered by this limit and could
be capped as well.

Hopefully the last release prior to 1.0, sorry in advance for a big PR

Previous attempt: https://github.com/paritytech/substrate/pull/13992

Resolves https://github.com/paritytech/polkadot-sdk/issues/748, resolves
https://github.com/paritytech/polkadot-sdk/issues/627

The goal is to move all system chains on Rococo (+ other testnets?) to
use async backing.

Starting with `asset-hub-rococo` to get feedback, before I do the rest.

## Related

Example: https://github.com/paritytech/polkadot-sdk/pull/1619/
Guide:
https://github.com/w3f/polkadot-wiki/blob/master/docs/maintain/maintain-guides-async-backing.md

---------

Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Dónal Murray <[email protected]>

Clean up all the old syntax.

---------

Co-authored-by: command-bot <>
Co-authored-by: gupnik <[email protected]>
Co-authored-by: Nikhil Gupta <[email protected]>
Co-authored-by: Maksym H <[email protected]>

This PR introduces the following changes:

- [x] Adds a `UniquesTransactor` to asset-hub-rococo
- [x] Adds a `UniquesTransactor` to asset-hub-westend

We can't add a transactor for `pallet-nfts` like we do for
`pallet-uniques` because `pallet-nfts` uses `nonfungibles_v2::Mutate`
instead of `nonfungibles::Mutate`, and making that work would be out of
scope of this PR.

With these modifications, reserve-based NFT cross-chain transfers can be
performed on asset-hub.

---------

Co-authored-by: joe petrowski <[email protected]>

Set up the `TakeFirstAssetTrader` trader for Westend and Rococo Asset
Hubs to cover XCM fees with sufficient assets.

This PR reintroduces previously
[removed](https://github.com/paritytech/polkadot-sdk/pull/1845) trader
setups, as it was decided to keep both traders, `TakeFirstAssetTrader`
and `SwapFirstAssetTrader`, during the transition period.

---------

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

This PR backports version bumps from release branch
`release-polkadot-v1.6.0` back to `master` and also moved `prdoc` files
related to the release to the appropriate folder

# Note for reviewer

Most changes are just syntax changes necessary for the new version.
Most important files should be the ones under the `xcm` folder.

# Description 

Added XCMv4.

## Removed `Multi` prefix
The following types have been renamed:
- MultiLocation -> Location
- MultiAsset -> Asset
- MultiAssets -> Assets
- InteriorMultiLocation -> InteriorLocation
- MultiAssetFilter -> AssetFilter
- VersionedMultiAsset -> VersionedAsset
- WildMultiAsset -> WildAsset
- VersionedMultiLocation -> VersionedLocation

In order to fix a name conflict, the `Assets` in `xcm-executor` were
renamed to `HoldingAssets`, as they represent assets in holding.

## Removed `Abstract` asset id

It was not being used anywhere and this simplifies the code.

Now assets are just constructed as follows:

```rust
let asset: Asset = (AssetId(Location::new(1, Here)), 100u128).into();
```

No need for specifying `Concrete` anymore.

## Outcome is now a named fields struct

Instead of

```rust
pub enum Outcome {
  Complete(Weight),
  Incomplete(Weight, Error),
  Error(Error),
}
```

we now have

```rust
pub enum Outcome {
  Complete { used: Weight },
  Incomplete { used: Weight, error: Error },
  Error { error: Error },
}
```

## Added Reanchorable trait

Now both locations and assets implement this trait, making it easier to
reanchor both.

## New syntax for building locations and junctions

Now junctions are built using the following methods:

```rust
let location = Location {
    parents: 1,
    interior: [Parachain(1000), PalletInstance(50), GeneralIndex(1984)].into()
};
```

or

```rust
let location = Location::new(1, [Parachain(1000), PalletInstance(50), GeneralIndex(1984)]);
```

And they are matched like so:

```rust
match location.unpack() {
  (1, [Parachain(id)]) => ...
  (0, Here) => ...,
  (1, [_]) => ...,
}
```

This syntax is mandatory in v4, and has been also implemented for v2 and
v3 for easier migration.

This was needed to make all sizes smaller.

# TODO
- [x] Scaffold v4
- [x] Port github.com/paritytech/polkadot/pull/7236
- [x] Remove `Multi` prefix
- [x] Remove `Abstract` asset id

---------

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

Implements an XCM executor `WeightTrader`, facilitating fee payments in
any asset that can be exchanged for a native asset.

A few constraints need to be observed:
- `buy_weight` and `refund` operations must be atomic, as another weight
trader implementation might be attempted in case of failure.
- swap credit must be utilized since there isn’t an account to which an
asset of some class can be deposited with a guarantee to meet the
existential deposit requirement. Also, operating with credits enhances
the efficiency of the weight trader -
https://github.com/paritytech/polkadot-sdk/pull/1677

related PRs:
- (depends) https://github.com/paritytech/polkadot-sdk/pull/2031
- (depends) https://github.com/paritytech/polkadot-sdk/pull/1677
- (caused) https://github.com/paritytech/polkadot-sdk/pull/1847
- (caused) https://github.com/paritytech/polkadot-sdk/pull/1876

// DONE: impl `OnUnbalanced` for a `fungible/s` credit
// DONE: make the trader free from a concept of a native currency and
drop few fallible conversions. related issue -
https://github.com/paritytech/polkadot-sdk/issues/1842
// DONE: tests

---------

Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: Liam Aharon <[email protected]>

- updates snowbridge crates to `0.9.0`
- updates Cargo.toml files in preparation for publishing to crates.io
- adds Kusama and Polkadot Snowbridge runtime config crates
- moves runtime tests from the Snowbridge subtree into the bridge hub
tests dir

---------

Co-authored-by: claravanstaden <Cats 4 life!>
Co-authored-by: Ron <[email protected]>

- Includes the introduction of the `fast-runtime` feature, which cleans
up our features
- Updates beacon client fork versions config to Sepolia's versions
- Cleanup of AgentIdOf

---------

Co-authored-by: Ron <[email protected]>
Co-authored-by: claravanstaden <Cats 4 life!>

- Updates all safe call filters to allow `system::authorize_upgrade`.
- Updates Coretime safe call filter to allow `sudo` and
`system_set_storage`.
- Update Coretime teleports to allow teleportation with other system
chains.

---------

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

After merging https://github.com/paritytech/polkadot-sdk/pull/2522
asset-hub-rococo and bridge-hub-rococo runtime versions need to be
bumped for their deployment.

---------

Co-authored-by: joe petrowski <[email protected]>

# Description

Adds Snowbridge to the Rococo bridge hub runtime. Includes config
changes required in Rococo asset hub.

---------

Co-authored-by: Alistair Singh <[email protected]>
Co-authored-by: ron <[email protected]>
Co-authored-by: Vincent Geddes <[email protected]>
Co-authored-by: claravanstaden <Cats 4 life!>

Adds the `authorize_upgrade` -> `enact_authorized_upgrade` pattern to
`frame-system`. This will be useful for upgrading bridged chains that
are under the governance of Polkadot without passing entire runtime Wasm
blobs over a bridge.

Notes:

- Changed `enact_authorized_upgrade` to `apply_authorized_upgrade`.
Personal opinion, "apply" more accurately expresses what it's doing. Can
change back if outvoted.
- Remove `check_version` in favor of two extrinsics, so as to make
_checked_ the default.
- Left calls in `parachain-system` and marked as deprecated to prevent
breaking the API. They just call into the `frame-system` functions.
- Updated `frame-system` benchmarks to v2 syntax.

---------

Co-authored-by: command-bot <>

closes https://github.com/paritytech/polkadot-sdk/issues/1842

Decoupling Pallet from the Concept of Native Currency

Currently, the pallet is intrinsically linked with the concept of native
currency, requiring users to provide implementations of the
`fungible::*` and `fungibles::*` traits to interact with native and non
native assets. This incapsulates some non-related to the pallet
complexity and makes it less adaptable in contexts where the native
currency concept is absent.

With this PR, the dependence on `fungible::*` for liquidity-supplying
assets has been removed. Instead, the native and non-native currencies'
handling is now overseen by a single type that implements the
`fungibles::*` traits. To simplify this integration, types have been
introduced to facilitate the creation of a union between `fungible::*`
and `fungibles::*` implementations, producing a unified `fungibles::*`
type.

One of the reasons driving these changes is the ambition to create a
more user-friendly API for the `SwapCredit` implementation. Given that
it interacts with two distinct credit types from `fungible` and
`fungibles`, a unified type was introduced. Clients now manage potential
conversion failures for those credit types. In certain contexts, it's
vital to guarantee that operations are fail-safe, like in this impl -
[PR](https://github.com/paritytech/polkadot-sdk/pull/1845), place in
[code](https://github.com/paritytech/polkadot-sdk/blob/20b85a5f

/cumulus/primitives/utility/src/lib.rs#L429).

Additional Updates:
- abstracted the pool ID and its account derivation logic via trait
bounds, along with common implementation offerings;
- removed `inc_providers` on a pool creation for the pool account;
- benchmarks:
-- swap complexity is N, not const;
-- removed `From<u128> + Into<u128>` bound from `T::Balance`;
-- removed swap/liquidity/.. amount constants, resolve them dynamically
based on pallet configuration;
-- migrated to v2 API;
- `OnUnbalanced` handler for the pool creation fee, replacing direct
transfers to a specified account ID;
- renamed `MultiAssetId` to `AssetKind` aligning with naming across
frame crates;

related PRs:
- (depends) https://github.com/paritytech/polkadot-sdk/pull/1677
- (caused) https://github.com/paritytech/polkadot-sdk/pull/2033
- (caused) https://github.com/paritytech/polkadot-sdk/pull/1876

---------

Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: Liam Aharon <[email protected]>

Introduces a swap implementation that allows the exchange of a credit
(aka Negative Imbalance) of one asset for a credit of another asset.

This is particularly useful when a credit swap is required but may not
have sufficient value to meet the ED constraint, hence cannot be
deposited to temp account before. An example use case is when XCM fees
are paid using an asset held in the XCM executor registry and has to be
swapped for native currency.

Additional Updates:
- encapsulates the existing `Swap` trait impl within a transactional
context, since partial storage mutation is possible when an error
occurs;
- supplied `Currency` and `Assets` impls must be implemented over the
same `Balance` type, the `AssetBalance` generic type is dropped. This
helps to avoid numerous type conversion and overflow cases. If those
types are different it should be handled outside of the pallet;
- `Box` asset kind on a pallet level, unbox on a runtime level - here
[why](https://substrate.stackexchange.com/questions/10039/boxed-argument-of-a-dispatchable/10103#10103);
- `path` uses `Vec` now, instead of `BoundedVec` since it is never used
in PoV;
- removes the `Transfer` event due to it's redundancy with the events
emitted by `fungible/s` implementations;
- modifies the `SwapExecuted` event type;

related issue: 
- https://github.com/paritytech/polkadot-sdk/issues/105

related PRs:
- (required for) https://github.com/paritytech/polkadot-sdk/pull/1845
- (caused) https://github.com/paritytech/polkadot-sdk/pull/1717

// DONE make the pallet work only with `fungibles` trait and make it
free from the concept of a `native` asset -
https://github.com/paritytech/polkadot-sdk/issues/1842

---------

Co-authored-by: joe petrowski <[email protected]>

Introduces `UnionOf` types, crafted to merge `fungible` and `fungibles`
implementations or two `fungibles` implementations into a single type
implementing `fungibles`.

This also addresses an issue where `ItemOf` initiates a double drop for
an imbalance type, leading to inaccurate total issuance accounting.

Find the application of these types in this PR -
[link](https://github.com/paritytech/polkadot-sdk/pull/2031), places in
code -
[1](https://github.com/paritytech/polkadot-sdk/blob/4ec7496f/cumulus/parachains/runtimes/assets/asset-hub-kusama/src/lib.rs#L327),
[2](https://github.com/paritytech/polkadot-sdk/blob/4ec7496f

/cumulus/parachains/runtimes/assets/asset-hub-kusama/src/lib.rs#L343).

---------

Co-authored-by: Liam Aharon <[email protected]>
Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: Oliver Tale-Yazdi <[email protected]>
Co-authored-by: joepetrowski <[email protected]>

This PR contains just a few clippy fixes and nits, which are, however,
relaxed by workspace clippy settings here:
https://github.com/paritytech/polkadot-sdk/blob/master/Cargo.toml#L483-L506

---------

Co-authored-by: Dmitry Sinyavin <[email protected]>
Co-authored-by: ordian <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: Bastian Köcher <[email protected]>

In the move from the old `Currency` traits to the new `fungible/s`
family of traits, we already had the `FungiblesAdapter` and
`NonFungiblesAdapter` for multiple fungible and non fungible assets
respectively. However, for handling only one fungible asset, we were
missing a `FungibleAdapter`, and so used the old `CurrencyAdapter`
instead. This PR aims to fill in that gap, and provide the new adapter
for more updated examples.

I marked the old `CurrencyAdapter` as deprecated as part of this PR, and
I'll change it to the new `FungibleAdapter` in a following PR.
The two stages are separated so as to not bloat this PR with some name
fixes in tests.

---------

Co-authored-by: command-bot <>

This PR backports `transaction_version` bump from `1.5.0` release back
to `master`

We currently use a bit of a hack in `.cargo/config` to make sure that
clippy isn't too annoying by specifying the list of lints.

There is now a stable way to define lints for a workspace. The only down
side is that every crate seems to have to opt into this so there's a
*few* files modified in this PR.

Dependencies:

- [x] PR that upgrades CI to use rust 1.74 is merged.

---------

Co-authored-by: joe petrowski <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Liam Aharon <[email protected]>

Co-authored-by: command-bot <>

We were not filtering for sibling parachains, but for sibling anything

---------

Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: command-bot <>

## Summary

This pull request proposes a solution for improved control of the
versioned XCM flow over the bridge (across different consensus chains)
and resolves the situation where the sending chain/consensus has already
migrated to a higher XCM version than the receiving chain/consensus.

## Problem/Motivation

The current flow over the bridge involves a transfer from AssetHubRococo
(AHR) to BridgeHubRococo (BHR) to BridgeHubWestend (BHW) and finally to
AssetHubWestend (AHW), beginning with a reserve-backed transfer on AHR.

In this process:
1. AHR sends XCM `ExportMessage` through `XcmpQueue`, incorporating XCM
version checks using the `WrapVersion` feature, influenced by
`pallet_xcm::SupportedVersion` (managed by
`pallet_xcm::force_xcm_version` or version discovery).

2. BHR handles the `ExportMessage` instruction, utilizing the latest XCM
version. The `HaulBlobExporter` converts the inner XCM to
[`VersionedXcm::from`](https://github.com/paritytech/polkadot-sdk/blob/63ac2471/polkadot/xcm/xcm-builder/src/universal_exports.rs#L465-L467),
also using the latest XCM version.

However, challenges arise:
- Incompatibility when BHW uses a different version than BHR. For
instance, if BHR migrates to **XCMv4** while BHW remains on **XCMv3**,
BHR's `VersionedXcm::from` uses `VersionedXcm::V4` variant, causing
encoding issues for BHW.
  ```
	/// Just a simulation of possible error, which could happen on BHW
	/// (this code is based on actual master without XCMv4)
	let encoded = hex_literal::hex!("0400");
	println!("{:?}", VersionedXcm::<()>::decode(&mut &encoded[..]));

Err(Error { cause: None, desc: "Could not decode `VersionedXcm`, variant
doesn't exist" })
  ``` 
- Similar compatibility issues exist between AHR and AHW.

## Solution

This pull request introduces the following solutions:

1. **New trait `CheckVersion`** - added to the `xcm` module and exposing
`pallet_xcm::SupportedVersion`. This enhancement allows checking the
actual XCM version for desired destinations outside of the `pallet_xcm`
module.

2. **Version Check in `HaulBlobExporter`** uses `CheckVersion` to check
known/configured destination versions, ensuring compatibility. For
example, in the scenario mentioned, BHR can store the version `3` for
BHW. If BHR is on XCMv4, it will attempt to downgrade the message to
version `3` instead of using the latest version `4`.

3. **Version Check in `pallet-xcm-bridge-hub-router`** - this check
ensures compatibility with the real destination's XCM version,
preventing the unnecessary sending of messages to the local bridge hub
if versions are incompatible.

These additions aim to improve the control and compatibility of XCM
flows over the bridge and addressing issues related to version
mismatches.

## Possible alternative solution

_(More investigation is needed, and at the very least, it should extend
to XCMv4/5. If this proves to be a viable option, I can open an RFC for
XCM.)._

Add the `XcmVersion` attribute to the `ExportMessage` so that the
sending chain can determine, based on what is stored in
`pallet_xcm::SupportedVersion`, the version the destination is using.
This way, we may not need to handle the version in `HaulBlobExporter`.

```
ExportMessage {
	network: NetworkId,
	destination: InteriorMultiLocation,
	xcm: Xcm<()>
	destination_xcm_version: Version, // <- new attritbute
},
```

```
pub trait ExportXcm {
        fn validate(
		network: NetworkId,
		channel: u32,
		universal_source: &mut Option<InteriorMultiLocation>,
		destination: &mut Option<InteriorMultiLocation>,
		message: &mut Option<Xcm<()>>,
                destination_xcm_version: Version, , // <- new attritbute
	) -> SendResult<Self::Ticket>;
```

## Future Directions

This PR does not fix version discovery over bridge, further
investigation will be conducted here:
https://github.com/paritytech/polkadot-sdk/issues/2417.

## TODO

- [x] `pallet_xcm` mock for tests uses hard-coded XCM version `2` -
change to 3 or lastest?
- [x] fix `pallet-xcm-bridge-hub-router`
- [x] fix HaulBlobExporter with version determination
[here](https://github.com/paritytech/polkadot-sdk/blob/2183669d/polkadot/xcm/xcm-builder/src/universal_exports.rs#L465)
- [x] add unit-tests to the runtimes
- [x] run benchmarks for `ExportMessage`
- [x] extend local run scripts about `force_xcm_version(dest, version)`
- [ ] when merged, prepare governance calls for Rococo/Westend
- [ ] add PRDoc

Part of: https://github.com/paritytech/parity-bridges-common/issues/2719

---------

Co-authored-by: command-bot <>