## 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/63ac2471aa0210f0ac9903bdd7d8f9351f9a635f/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/2183669d05f9b510f979a0cc3c7847707bacba2e/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 <>
# 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 <>
On extrinsics/call, ensure local XCM execution is complete/successful.
Otherwise, fail the extrinsic so that state changes don't get committed
to the db.
Added regression tests that fail without the fix.
fixes#2237
---------
Co-authored-by: Adrian Catangiu <adrian@parity.io>
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.
## 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 <franciscoaguirreperez@gmail.com>
Co-authored-by: Branislav Kontur <bkontur@gmail.com>
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 <alex.theissen@me.com>
Co-authored-by: command-bot <>
closes https://github.com/paritytech/polkadot-sdk/issues/1882
## Breaking Changes
This PR introduces a new item to `pallet_balances::Config`:
```diff
trait Config {
++ type RuntimeFreezeReasons;
}
```
This value is only used to check it against `type MaxFreeze`. A similar
check has been added for `MaxHolds` against `RuntimeHoldReasons`, which
is already given to `pallet_balances`.
In all contexts, you should pass the real `RuntimeFreezeReasons`
generated by `construct_runtime` to `type RuntimeFreezeReasons`. Passing
`()` would also work, but it would imply that the runtime uses no
freezes at all.
---------
Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Combination of paritytech/polkadot#7005, its addon PR
paritytech/polkadot#7585 and its companion paritytech/cumulus#2433.
This PR introduces a new XcmFeesToAccount struct which implements the
`FeeManager` trait, and assigns this struct as the `FeeManager` in the
XCM config for all runtimes.
The struct simply deposits all fees handled by the XCM executor to a
specified account. In all runtimes, the specified account is configured
as the treasury account.
XCM __delivery__ fees are now being introduced (unless the root origin
is sending a message to a system parachain on behalf of the originating
chain).
# Note for reviewers
Most file changes are tests that had to be modified to account for the
new fees.
Main changes are in:
- cumulus/pallets/xcmp-queue/src/lib.rs <- To make it track the delivery
fees exponential factor
- polkadot/xcm/xcm-builder/src/fee_handling.rs <- Added. Has the
FeeManager implementation
- All runtime xcm_config files <- To add the FeeManager to the XCM
configuration
# Important note
After this change, instructions that create and send a new XCM (Query*,
Report*, ExportMessage, InitiateReserveWithdraw, InitiateTeleport,
DepositReserveAsset, TransferReserveAsset, LockAsset and RequestUnlock)
will require the corresponding origin account in the origin register to
pay for transport delivery fees, and the onward message will fail to be
sent if the origin account does not have the required amount. This
delivery fee is on top of what we already collect as tx fees in
pallet-xcm and XCM BuyExecution fees!
Wallet UIs that want to expose the new delivery fee can do so using the
formula:
```
delivery_fee_factor * (base_fee + encoded_msg_len * per_byte_fee)
```
where the delivery fee factor can be obtained from the corresponding
pallet based on which transport you are using (UMP, HRMP or bridges),
the base fee is a constant, the encoded message length from the message
itself and the per byte fee is the same as the configured per byte fee
for txs (i.e. `TransactionByteFee`).
---------
Co-authored-by: Branislav Kontur <bkontur@gmail.com>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Co-authored-by: Giles Cope <gilescope@gmail.com>
Co-authored-by: command-bot <>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Two old functions should be deprecated and have their code altered in
line with capabilities of XCMv2 and above.
This means we can use the proper `Unlimited` form of weight limit rather
than guessing weight from the local chain.
`VersionedMigration` has become somewhat widely used for handling
version bumps in migrations the last few months.
It is currently behind the `experimental` feature flag, requiring every
pallet that writes a new migration with version bumps to set up the
`experimental` flag in their own Cargo.tomls, and also for every runtime
using these pallets to explicitly enable the `experimental` flag for
each pallet.
This is becoming quite verbose, and I can only see the number of pallets
requiring the experimental flag increasing for no other reason than
using what has become a commonly used feature.
Additionally, I'm writing migration docs and would like to avoid
stepping through how to use the `experimental` feature to get
`VersionedMigration` working.
Since the feature has been used in production for some time now without
any reported issues, is becoming commonly used and ready to advertise in
docs, I feel this is a good time to make it non-experimental.
* Rename `polkadot-parachain` to `polkadot-parachain-primitives`
While doing this it also fixes some last `rustdoc` issues and fixes
another Cargo warning related to `pallet-paged-list`.
* Fix compilation
* ".git/.scripts/commands/fmt/fmt.sh"
* Fix XCM docs
---------
Co-authored-by: command-bot <>
* Move XCM query functionality to trait
* Fix tests
* Add PayOverXcm implementation
* fix the PayOverXcm trait to compile
* moved doc comment out of trait implmeentation and to the trait
* PayOverXCM documentation
* Change documentation a bit
* Added empty benchmark methods implementation and changed docs
* update PayOverXCM to convert AccountIds to MultiLocations
* Implement benchmarking method
* Change v3 to latest
* Descend origin to an asset sender (#6970)
* descend origin to an asset sender
* sender as tuple of dest and sender
* Add more variants to the QueryResponseStatus enum
* Change Beneficiary to Into<[u8; 32]>
* update PayOverXcm to return concrete errors and use AccountId as sender
* use polkadot-primitives for AccountId
* fix dependency to use polkadot-core-primitives
* force Unpaid instruction to the top of the instructions list
* modify report_outcome to accept interior argument
* use new_query directly for building final xcm query, instead of report_outcome
* fix usage of new_query to use the XcmQueryHandler
* fix usage of new_query to use the XcmQueryHandler
* tiny method calling fix
* xcm query handler (#7198)
* drop redundant query status
* rename ReportQueryStatus to OuterQueryStatus
* revert rename of QueryResponseStatus
* update mapping
* Update xcm/xcm-builder/src/pay.rs
Co-authored-by: Gavin Wood <gavin@parity.io>
* Updates
* Docs
* Fix benchmarking stuff
* Destination can be determined based on asset_kind
* Tweaking API to minimise clones
* Some repotting and docs
---------
Co-authored-by: Anthony Alaribe <anthonyalaribe@gmail.com>
Co-authored-by: Muharem Ismailov <ismailov.m.h@gmail.com>
Co-authored-by: Anthony Alaribe <anthony.alaribe@parity.io>
Co-authored-by: Gavin Wood <gavin@parity.io>
* Tools for unique topic references
* Formatting
* Naming
* Repot into routing.rs.
* More things done
* Universal Exporter supports topic-as-reference
* Some tests for the topic routing
* More tests
* Paid bridge tests
* Add message ID to sending events
* Formatting
* fix and integrate into test nets
* Move DenyThenTry and friend from Cumulus
* Append SetTopic rather than prepend
* Docs
* Docs
* Work with new ProcessMessage ID API
* Formatting
* Fix build
* Fixes
* Formatting
* Update xcm/xcm-builder/src/barriers.rs
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
* Update xcm/xcm-builder/src/routing.rs
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
* Docs
* Rename message_hash
* Formatting
* ".git/.scripts/commands/fmt/fmt.sh"
* Rename
* Another Rename
* ".git/.scripts/commands/fmt/fmt.sh"
* ".git/.scripts/commands/fmt/fmt.sh"
* Update xcm/xcm-builder/src/routing.rs
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
---------
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: command-bot <>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
* Properly set the pricing for the DMP router
* Publicize price types
* Use FixedU128 instead of Percent
* Add sp-arithmetic as a dependency for rococo runtime
* Add sp-arithmetic as a dependency to all runtimes
* Remove duplicate import
* Add missing import
* Fix tests
* Create an appropriate QueueDownwardMessageError variant
* Recalculate delivery fee factor based on past queue sizes
* Remove unused error variant
* Fixes
* Fixes
* Remove unused imports
* Rewrite fee factor update mechanism
* Remove unused imports
* Fixes
* Update runtime/parachains/src/dmp.rs
Co-authored-by: Squirrel <gilescope@gmail.com>
* Make DeliveryFeeFactor be a StorageMap keyed on ParaIds
* Fixes
* introduce limit for fee increase on dmp queue
* add message_size based fee factor to increment_fee_factor
* change message_size fee rate to correct value
* fix div by 0 error
* bind limit to variable
* fix message_size_factor and add DeliveryFeeFactor test
* add test for ExponentialPrice implementation
* make test formula based
* make delivery fee factor test formula based
* add max value test for DeliveryFeeFactor and move limit to config
* change threshold back to dynamic value and fix tests
* fmt
* suggested changes and fmt
* small stylistic change
* fmt
* change to tokenlocation
* small fixes
* fmt
* remove sp_arithmetic dependency
* Update runtime/parachains/src/dmp.rs
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
---------
Co-authored-by: Squirrel <gilescope@gmail.com>
Co-authored-by: Just van Stam <just.van.stam@gmail.com>
Co-authored-by: Just van Stam <vstam1@users.noreply.github.com>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
* Happy New Year!
* Remove year entierly
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
* Remove years from copyright notice in the entire repo
---------
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
* Ensure for a configurable origin in XCM (#6442), cherry picked from
5ae05e1a957857c449a43d8759a21292d03fd049
Add new associated type, AdminOrigin, bounded by EnsureOrigin trait in
XCM pallet. Replace ensure_root() with ensure_origin() from a
EnsureOrigin trait. Set AdminOrigin as EnsureRoot<AccountId> in xcm
configs.
* cargo fmt
* small stylistic change
---------
Co-authored-by: serkul <serkul@pop-os.localdomain>
* Some renames
* Fix
* Fix build for new APIs
* Remove diener
* Fixes
* Fixes
* Fix integration tests
* Fixes
* fix nis issuance
* Update Cargo.toml
* Polkadot doesn't have freezes/holds yet
* No networks use freezes/holds
* update lockfile for {"substrate"}
* Fix tests
There are more failing tests; just starting with the easy ones.
Reserved balance does not count towards ED anymore, therefore reducing
all the reserves by ED (1).
Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
* Fixes for Polkadot pallets
* Fix parachains benchmarks
* Update Substrate
Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
---------
Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: parity-processbot <>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
* Remove use of Store trait from runtime directory
* Remove Store trait usage from xcm directory
* Run cargo fmt
* update lockfile for {"substrate"}
---------
Co-authored-by: parity-processbot <>
* Update benchmark's successful origin api
* rustfmt
* unwrap for indirect origin dep
* replace unwrap by expect with a message
---------
Co-authored-by: parity-processbot <>
Branislav Kontur