# 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>
Follow up to fix a bug from #1814 discovered in XCM emulator testing.
I mistakenly thought that checking out an asset would withdraw it from
the sender. This actually withdraws the asset before checking out.
---------
Co-authored-by: Adrian Catangiu <adrian@parity.io>
Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>
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 <git@kchr.de>
Francisco Aguirre