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]>

To deploy https://github.com/paritytech/polkadot-sdk/pull/3029

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

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.

- Prepares for the Deneb hardfork on Sepolia testnet on 31 January
(needs to be deployed to Rococo before then)
- Removes `beacon-minimal-spec` flag for simpler config
- Adds test comments

---------

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

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]>

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 <>

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]>

Update bridges subtree

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]>

- 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 <>

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]>

This PR adds possibility for relay chain governance to halt and resume
bridge pallets using XCM calls. Following calls are enabled over XCM for
the `root` origin: `pallet_bridge_grandpa::set_operating_mode`,
`pallet_bridge_parachains::set_operating_mode` and
`pallet_bridge_messages::set_operating_mode`.

This PR adds [Rococo
People](https://github.com/paritytech/polkadot-sdk/pull/2281) <> [Rococo
Bulletin](https://github.com/zdave-parity/polkadot-bulletin-chain) to
the Rococo Bridge Hub code. There's a couple of things left to do here:
- [x] add remaining tests - it'd need some refactoring in the
`bridge-hub-test-utils` - will do in a separate PR;
- [x] actually run benchmarks for new messaging pallet (do we have bot
nowadays?).

The reason why I'm opening it before this ^^^ is ready, is that I'd like
to hear others opinion on how to deal with hacks with that bridge.
Initially I was assuming that Rococo Bulletin will be the 1:1 copy of
the Polkadot Bulletin (to avoid maintaining multiple
runtimes/releases/...), so you can see many `PolkadotBulletin` mentions
in this PR, even though we are going to bridge with the parallel chain
(`RococoBulletin`). That's because e.g. pallet names from
`construct_runtime` are affecting runtime storage keys and bridges are
using runtime storage proofs => it is important to use names that the
Bulletin chain expects.

But in the end, this hack won't work - we can't use Polkadot Bulletin
runtime to bridge with Rococo Bridge Hub, because Polkadot Bulletin
expects Polkadot Bridge hub to use `1002` parachain id and Rococo Bridge
Hub seats on the `1013`. This also affects storage keys using in
bridging, so I had to add the [`rococo`
feature](https://github.com/svyatonik/polkadot-bulletin-chain/blob/add-bridge-pallets/runtime/Cargo.toml#L198)
to the Bulletin chain. So now we can actually alter its runtime and
adapt it for Rococo.

So the question here is - what's better for us here
- to leave everything as is (seems hacky and non-trivial);
- change Bulletin chain runtime when `rococo` feature is used - e.g. use
proper names there (`WithPolkadotGrandpa` -> `WithRococoGrandpa`, ...)
- add another set of pallets to the Bulletin chain runtime to bridge
with Rococo and never use them in production. Similar to hack that we
had in Rococo/Wococo

cc @acatangiu @bkontur @serban300 

also cc @joepetrowski

 as the main "client" of this bridge

---

A couple words on how this bridge is different from the Rococo <>
Westend bridge:
- it is a bridge with a chain that uses GRANDPA finality, not the
parachain finality (hence the tests needs to be changed);
- it is a fee-free bridge. So
`AllowExplicitUnpaidExecutionFrom<Equals<SiblingPeople>>` + we are not
paying any rewards to relayers (apart from compensating transaction
costs).

---------

Signed-off-by: dependabot[bot] <[email protected]>
Signed-off-by: Andrei Sandu <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Andrei Sandu <[email protected]>
Co-authored-by: Egor_P <[email protected]>
Co-authored-by: command-bot <>

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`

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 <>

This PR introduces a script and some templates to use the prdoc involved
in a release and build:
- the changelog
- a simple draft of audience documentation

Since the prdoc presence was enforced in the middle of the version
1.5.0, not all PRs did come with a `prdoc` file.
This PR creates all the missing `prdoc` files with some minimum content
allowing to properly generate the changelog.
The generated content is **not** suitable for the audience
documentation.

The audience documentation will be possible with the next version, when
all PR come with a proper `prdoc`.

## Assumptions

- the prdoc files for release `vX.Y.Z` have been moved under
`prdoc/X.Y.Z`
- the changelog requires for now for the prdoc files to contain author +
topic. Thos fields are optional.

The build script can  be called as:
```
VERSION=X.Y.Z ./scripts/release/build-changelogs.sh
```

Related:
-  #1408

---------

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

As suggested in this thread:
https://github.com/polkadot-fellows/runtimes/pull/87#discussion_r1400237122

We already have the `IsChildSystemParachain`, which may be used at relay
chain, but it can't be used at a parachain level. So let's use
`AllSiblingSystemParachains` for that. I was thinking about
`AllSystemParachains`, but it may cause wrong impression that it can be
used at a relay chain level.

---------

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

## Summary

This PR aligns Rococo/Westend bridge with latest Bridges repo
development:
- https://github.com/paritytech/parity-bridges-common/pull/2727
- https://github.com/paritytech/parity-bridges-common/pull/2728
- https://github.com/paritytech/parity-bridges-common/pull/2729




Part of: https://github.com/paritytech/parity-bridges-common/issues/2452

# Motivation (+testing)

### Enable easy `ForeignAssets` transfers using `pallet-xcm` 

We had just previously added capabilities to teleport fees during
reserve-based transfers, but what about reserve-transferring fees when
needing to teleport some non-fee asset?

This PR aligns everything under either explicit reserve-transfer,
explicit teleport, or this new flexible `transfer_assets()` which can
mix and match as needed with fewer artificial constraints imposed to the
user.

This will enable, for example, a (non-system) parachain to teleport
their `ForeignAssets` assets to AssetHub while using DOT to pay fees.
(the assets are teleported - as foreign assets should from their owner
chain - while DOT used for fees can only be reserve-based transferred
between said parachain and AssetHub).

Added `xcm-emulator` tests for this scenario ^.

# Description

Reverts `(limited_)reserve_transfer_assets` to only allow reserve-based
transfers for all `assets` including fees.

Similarly `(limited_)teleport_assets` only allows teleports for all
`assets` including fees.
    
For complex combinations of asset transfers where assets and fees may
have different reserves or different reserve/teleport trust
configurations, users can use the newly added `transfer_assets()`
extrinsic which is more flexible in allowing more complex scenarios.

`assets` (excluding `fees`) must have same reserve location or otherwise
be teleportable to `dest`.
No limitations imposed on `fees`.

- for local reserve: transfer assets to sovereign account of destination
chain and forward a notification XCM to `dest` to mint and deposit
reserve-based assets to `beneficiary`.
- for destination reserve: burn local assets and forward a notification
to `dest` chain to withdraw the reserve assets from this chain's
sovereign account and deposit them to `beneficiary`.
- for remote reserve: burn local assets, forward XCM to reserve chain to
move reserves from this chain's SA to `dest` chain's SA, and forward
another XCM to `dest` to mint and deposit reserve-based assets to
`beneficiary`.
- for teleports: burn local assets and forward XCM to `dest` chain to
mint/teleport assets and deposit them to `beneficiary`.

## Review notes

Only around 500 lines are prod code (see `pallet_xcm/src/lib.rs`), the
rest of the PR is new tests and improving existing tests.

---------

Co-authored-by: command-bot <>

Removes obsolete fields from the `QueueConfigData` structure. For the
remaining fields, if they use the old defaults, we replace them with the
new defaults.

Resolves: https://github.com/paritytech/polkadot-sdk/issues/1795

## Overview

This PR aligns the `spec_version` formatting to the [recent
changes](https://github.com/polkadot-fellows/runtimes/pull/26/files#diff-efa4caeb17487ecb13d8f5eb7863c3241d84afa2e73fbf25909a2ca89df0f362R142)
made for the Polkadot/Kusama runtimes.

It also backports the latest version `v1.4.0` bumps as `1_004_000`.

## Details

During the switch from `v0.9` to `v1.x`, the format of the
`spec_version` was modified from: `(M)m_ppp` for a runtime considered on
version `M.m.pp`. For instance `0.9.42` had a `spec_version` of `9420`.

With the transition to `v1.x`, the format was changed to a bigger number
(still `u32`) formatted as `MM_mm_ppp` where `1.2.3` would be stored as
`01_02_003`.

This PR aligns the format with that has been introduced in the
fellowship repo: `MMM_mmm_ppp`.

---------

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

DMP queue migration is complete and the pallet should be removed to fix
the check runtime upgrade CI.

<img width="1501" alt="Screenshot 2023-11-24 at 16 05 37"
src="https://github.com/paritytech/polkadot-sdk/assets/16665596/ee1da6bb-2756-4423-8085-1e4c73553ad5">

<img width="1501" alt="Screenshot 2023-11-24 at 16 06 44"
src="https://github.com/paritytech/polkadot-sdk/assets/16665596/03f3e88f-aed8-4eaa-aab6-7998f72258be">

This PR fixes two things:
- relax `force_default_xcm_version` for testnet system parachains (e.g.
BridgeHubWestend has now 2 and there is no way to change it to 3, so we
need to call `force_xcm_version(3)` for every parachain that it is
connected to, because we send XCMv3 messages)
- add `Storage` item to `PolkadotXcm` pallet definition (now we cannot
see storage items for `pallet_xcm` in PJS)


## TODO

- [ ] when merged open PR to `polkadot-fellows/runtimes` repo

Missed in https://github.com/paritytech/polkadot-sdk/pull/1672

Rococo<>Wococo bridge is replaced by Rococo<Westend bridge, so this PR
removes unneeded code.

- [x] update bridges subtree after
https://github.com/paritytech/parity-bridges-common/pull/2692

---------

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

Fixes https://github.com/paritytech/polkadot-sdk/issues/106

Port of cumulus PR https://github.com/paritytech/cumulus/pull/2960

This PR adds the ability to bid for collator slots even after the max
number of collators have already registered. This eliminates the first
come, first served mechanism that was in place before.

Key changes:
- added `update_bond` extrinsic to allow registered candidates to adjust
their bonds in order to dynamically control their bids
- added `take_candidate_slot` extrinsic to try to replace an already
existing candidate by bidding more than them
- candidates are now kept in a sorted list in the pallet storage, where
the top `DesiredCandidates` out of `MaxCandidates` candidates in the
list will be selected by the session pallet as collators
- if the candidacy bond is increased through a `set_candidacy_bond`
call, candidates which don't meet the new bond requirements are kicked


# Checklist

- [ ] My PR includes a detailed description as outlined in the
"Description" section above
- [ ] My PR follows the [labeling
requirements](https://github.com/paritytech/polkadot-sdk/blob/master/docs/CONTRIBUTING.md#process)
of this project (at minimum one label for `T` required)
- [ ] I have made corresponding changes to the documentation (if
applicable)
- [ ] I have added tests that prove my fix is effective or that my
feature works (if applicable)
- [ ] If this PR alters any external APIs or interfaces used by
Polkadot, the corresponding Polkadot PR is ready as well as the
corresponding Cumulus PR (optional)

---------

Signed-off-by: georgepisaltu <[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]>

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 <>

This PR changes the registration order of the `MessageQueue` pallet so
that it is registered last.

This is necessary so that the
[on_initialize](https://github.com/Snowfork/snowbridge/blob/df8d5da8/parachain/pallets/outbound-queue/src/lib.rs#L267)
hooks for Snowbridge can run before `MessageQueue` delivers messages
using its own `on_initialize`.

Generally, I think this is preferable regardless of Snowbridge's
particular requirements. Other pallets may want to do housekeeping
before MessageQueue starts delivering messages.

I'm hoping this PR, if accepted, can be included in the same release as
https://github.com/paritytech/polkadot-sdk/pull/1246. As otherwise,
changing the order of pallet registration is an ABI-breaking change.