Currently the xcm-executor returns an `Unimplemented` error if it
receives any HRMP-related instruction.
What I propose here, which is what we are currently doing in our forked
executor at polimec, is to introduce a trait implemented by the executor
which will handle those instructions.
This way, if parachains want to keep the default behavior, they just use
`()` and it will return unimplemented, but they can also implement their
own logic to establish HRMP channels with other chains in an automated
fashion, without requiring to go through governance.
Our implementation is mentioned in the [polkadot HRMP
docs](https://arc.net/l/quote/hduiivbu), and it was suggested to us to
submit a PR to add these changes to polkadot-sdk.
---------
Co-authored-by: Branislav Kontur <bkontur@gmail.com>
Co-authored-by: command-bot <>
I found out during the cleanup of this deprecation message in the
`polkadot-fellows` repository that we deprecated `CurrencyAdapter`
without making the recommended changes.
## TODO
- [ ] fix `polkadot-fellows` bump to 1.6.0
https://github.com/polkadot-fellows/runtimes/pull/159
---------
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
# 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 <kungfukeith11@gmail.com>
Juan Ignacio Rios