Type Alias xcm_simulator::opaque::Instruction

pub type Instruction = Instruction<()>;

The basic concrete type of Instruction, which doesn’t make any assumptions about the format of a call other than it is pre-encoded.

Aliased Type

enum Instruction {
    WithdrawAsset(Assets),
    ReserveAssetDeposited(Assets),
    ReceiveTeleportedAsset(Assets),
    QueryResponse {
        query_id: u64,
        response: Response,
        max_weight: Weight,
        querier: Option<Location>,
    },
    TransferAsset {
        assets: Assets,
        beneficiary: Location,
    },
    TransferReserveAsset {
        assets: Assets,
        dest: Location,
        xcm: Xcm<()>,
    },
    Transact {
        origin_kind: OriginKind,
        call: DoubleEncoded<()>,
    },
    HrmpNewChannelOpenRequest {
        sender: u32,
        max_message_size: u32,
        max_capacity: u32,
    },
    HrmpChannelAccepted {
        recipient: u32,
    },
    HrmpChannelClosing {
        initiator: u32,
        sender: u32,
        recipient: u32,
    },
    ClearOrigin,
    DescendOrigin(Junctions),
    ReportError(QueryResponseInfo),
    DepositAsset {
        assets: AssetFilter,
        beneficiary: Location,
    },
    DepositReserveAsset {
        assets: AssetFilter,
        dest: Location,
        xcm: Xcm<()>,
    },
    ExchangeAsset {
        give: AssetFilter,
        want: Assets,
        maximal: bool,
    },
    InitiateReserveWithdraw {
        assets: AssetFilter,
        reserve: Location,
        xcm: Xcm<()>,
    },
    InitiateTeleport {
        assets: AssetFilter,
        dest: Location,
        xcm: Xcm<()>,
    },
    ReportHolding {
        response_info: QueryResponseInfo,
        assets: AssetFilter,
    },
    BuyExecution {
        fees: Asset,
        weight_limit: WeightLimit,
    },
    RefundSurplus,
    SetErrorHandler(Xcm<()>),
    SetAppendix(Xcm<()>),
    ClearError,
    SetAssetClaimer {
        location: Location,
    },
    ClaimAsset {
        assets: Assets,
        ticket: Location,
    },
    Trap(u64),
    SubscribeVersion {
        query_id: u64,
        max_response_weight: Weight,
    },
    UnsubscribeVersion,
    BurnAsset(Assets),
    ExpectAsset(Assets),
    ExpectOrigin(Option<Location>),
    ExpectError(Option<(u32, Error)>),
    ExpectTransactStatus(MaybeErrorCode),
    QueryPallet {
        module_name: Vec<u8>,
        response_info: QueryResponseInfo,
    },
    ExpectPallet {
        index: u32,
        name: Vec<u8>,
        module_name: Vec<u8>,
        crate_major: u32,
        min_crate_minor: u32,
    },
    ReportTransactStatus(QueryResponseInfo),
    ClearTransactStatus,
    UniversalOrigin(Junction),
    ExportMessage {
        network: NetworkId,
        destination: Junctions,
        xcm: Xcm<()>,
    },
    LockAsset {
        asset: Asset,
        unlocker: Location,
    },
    UnlockAsset {
        asset: Asset,
        target: Location,
    },
    NoteUnlockable {
        asset: Asset,
        owner: Location,
    },
    RequestUnlock {
        asset: Asset,
        locker: Location,
    },
    SetFeesMode {
        jit_withdraw: bool,
    },
    SetTopic([u8; 32]),
    ClearTopic,
    AliasOrigin(Location),
    UnpaidExecution {
        weight_limit: WeightLimit,
        check_origin: Option<Location>,
    },
    PayFees {
        asset: Asset,
    },
    InitiateTransfer {
        destination: Location,
        remote_fees: Option<AssetTransferFilter>,
        preserve_origin: bool,
        assets: Vec<AssetTransferFilter>,
        remote_xcm: Xcm<()>,
    },
    ExecuteWithOrigin {
        descendant_origin: Option<Junctions>,
        xcm: Xcm<()>,
    },
}

Variants

WithdrawAsset(Assets)

Withdraw asset(s) (assets) from the ownership of origin and place them into the Holding Register.

• assets: The asset(s) to be withdrawn into holding.

Kind: Command.

Errors:

ReserveAssetDeposited(Assets)

Asset(s) (assets) have been received into the ownership of this system on the origin system and equivalent derivatives should be placed into the Holding Register.

• assets: The asset(s) that are minted into holding.

Safety: origin must be trusted to have received and be storing assets such that they may later be withdrawn should this system send a corresponding message.

Kind: Trusted Indication.

Errors:

ReceiveTeleportedAsset(Assets)

Asset(s) (assets) have been destroyed on the origin system and equivalent assets should be created and placed into the Holding Register.

• assets: The asset(s) that are minted into the Holding Register.

Safety: origin must be trusted to have irrevocably destroyed the corresponding assets prior as a consequence of sending this message.

Kind: Trusted Indication.

Errors:

QueryResponse

Respond with information that the local system is expecting.

• query_id: The identifier of the query that resulted in this message being sent.
• response: The message content.
• max_weight: The maximum weight that handling this response should take.
• querier: The location responsible for the initiation of the response, if there is one. In general this will tend to be the same location as the receiver of this message. NOTE: As usual, this is interpreted from the perspective of the receiving consensus system.

Safety: Since this is information only, there are no immediate concerns. However, it should be remembered that even if the Origin behaves reasonably, it can always be asked to make a response to a third-party chain who may or may not be expecting the response. Therefore the querier should be checked to match the expected value.

Kind: Information.

Errors:

Fields

query_id: u64

response: Response

max_weight: Weight

querier: Option<Location>

TransferAsset

Withdraw asset(s) (assets) from the ownership of origin and place equivalent assets under the ownership of beneficiary.

• assets: The asset(s) to be withdrawn.
• beneficiary: The new owner for the assets.

Safety: No concerns.

Kind: Command.

Errors:

Fields

assets: Assets

beneficiary: Location

TransferReserveAsset

Withdraw asset(s) (assets) from the ownership of origin and place equivalent assets under the ownership of dest within this consensus system (i.e. its sovereign account).

Send an onward XCM message to dest of ReserveAssetDeposited with the given xcm.

• assets: The asset(s) to be withdrawn.
• dest: The location whose sovereign account will own the assets and thus the effective beneficiary for the assets and the notification target for the reserve asset deposit message.
• xcm: The instructions that should follow the ReserveAssetDeposited instruction, which is sent onwards to dest.

Safety: No concerns.

Kind: Command.

Errors:

Fields

assets: Assets

dest: Location

xcm: Xcm<()>

Transact

Apply the encoded transaction call, whose dispatch-origin should be origin as expressed by the kind of origin origin_kind.

The Transact Status Register is set according to the result of dispatching the call.

• origin_kind: The means of expressing the message origin as a dispatch origin.
• call: The encoded transaction to be applied.

Safety: No concerns.

Kind: Command.

Errors:

Fields

origin_kind: OriginKind

call: DoubleEncoded<()>

HrmpNewChannelOpenRequest

A message to notify about a new incoming HRMP channel. This message is meant to be sent by the relay-chain to a para.

• sender: The sender in the to-be opened channel. Also, the initiator of the channel opening.
• max_message_size: The maximum size of a message proposed by the sender.
• max_capacity: The maximum number of messages that can be queued in the channel.

Safety: The message should originate directly from the relay-chain.

Kind: System Notification

Fields

sender: u32

max_message_size: u32

max_capacity: u32

HrmpChannelAccepted

A message to notify about that a previously sent open channel request has been accepted by the recipient. That means that the channel will be opened during the next relay-chain session change. This message is meant to be sent by the relay-chain to a para.

Safety: The message should originate directly from the relay-chain.

Kind: System Notification

Errors:

Fields

recipient: u32

HrmpChannelClosing

A message to notify that the other party in an open channel decided to close it. In particular, initiator is going to close the channel opened from sender to the recipient. The close will be enacted at the next relay-chain session change. This message is meant to be sent by the relay-chain to a para.

Safety: The message should originate directly from the relay-chain.

Kind: System Notification

Errors:

Fields

initiator: u32

sender: u32

recipient: u32

ClearOrigin

Clear the origin.

This may be used by the XCM author to ensure that later instructions cannot command the authority of the origin (e.g. if they are being relayed from an untrusted source, as often the case with ReserveAssetDeposited).

Safety: No concerns.

Kind: Command.

Errors:

DescendOrigin(Junctions)

Mutate the origin to some interior location.

Kind: Command

Errors:

ReportError(QueryResponseInfo)

Immediately report the contents of the Error Register to the given destination via XCM.

A QueryResponse message of type ExecutionOutcome is sent to the described destination.

• response_info: Information for making the response.

Kind: Command

Errors:

DepositAsset

Remove the asset(s) (assets) from the Holding Register and place equivalent assets under the ownership of beneficiary within this consensus system.

• assets: The asset(s) to remove from holding.
• beneficiary: The new owner for the assets.

Kind: Command

Errors:

Fields

assets: AssetFilter

beneficiary: Location

DepositReserveAsset

Remove the asset(s) (assets) from the Holding Register and place equivalent assets under the ownership of dest within this consensus system (i.e. deposit them into its sovereign account).

Send an onward XCM message to dest of ReserveAssetDeposited with the given effects.

• assets: The asset(s) to remove from holding.
• dest: The location whose sovereign account will own the assets and thus the effective beneficiary for the assets and the notification target for the reserve asset deposit message.
• xcm: The orders that should follow the ReserveAssetDeposited instruction which is sent onwards to dest.

Kind: Command

Errors:

Fields

assets: AssetFilter

dest: Location

xcm: Xcm<()>

ExchangeAsset

Remove the asset(s) (want) from the Holding Register and replace them with alternative assets.

The minimum amount of assets to be received into the Holding Register for the order not to fail may be stated.

• give: The maximum amount of assets to remove from holding.
• want: The minimum amount of assets which give should be exchanged for.
• maximal: If true, then prefer to give as much as possible up to the limit of give and receive accordingly more. If false, then prefer to give as little as possible in order to receive as little as possible while receiving at least want.

Kind: Command

Errors:

Fields

give: AssetFilter

want: Assets

maximal: bool

InitiateReserveWithdraw

Remove the asset(s) (assets) from holding and send a WithdrawAsset XCM message to a reserve location.

• assets: The asset(s) to remove from holding.
• reserve: A valid location that acts as a reserve for all asset(s) in assets. The sovereign account of this consensus system on the reserve location will have appropriate assets withdrawn and effects will be executed on them. There will typically be only one valid location on any given asset/chain combination.
• xcm: The instructions to execute on the assets once withdrawn on the reserve location.

Kind: Command

Errors:

Fields

assets: AssetFilter

reserve: Location

xcm: Xcm<()>

InitiateTeleport

Remove the asset(s) (assets) from holding and send a ReceiveTeleportedAsset XCM message to a dest location.

• assets: The asset(s) to remove from holding.
• dest: A valid location that respects teleports coming from this location.
• xcm: The instructions to execute on the assets once arrived on the destination location.

NOTE: The dest location MUST respect this origin as a valid teleportation origin for all assets. If it does not, then the assets may be lost.

Kind: Command

Errors:

Fields

assets: AssetFilter

dest: Location

xcm: Xcm<()>

ReportHolding

Report to a given destination the contents of the Holding Register.

A QueryResponse message of type Assets is sent to the described destination.

• response_info: Information for making the response.
• assets: A filter for the assets that should be reported back. The assets reported back will be, asset-wise, the lesser of this value and the holding register. No wildcards will be used when reporting assets back.

Kind: Command

Errors:

Fields

response_info: QueryResponseInfo

assets: AssetFilter

BuyExecution

Pay for the execution of some XCM xcm and orders with up to weight picoseconds of execution time, paying for this with up to fees from the Holding Register.

• fees: The asset(s) to remove from the Holding Register to pay for fees.
• weight_limit: The maximum amount of weight to purchase; this must be at least the expected maximum weight of the total XCM to be executed for the AllowTopLevelPaidExecutionFrom barrier to allow the XCM be executed.

Kind: Command

Errors:

Fields

fees: Asset

weight_limit: WeightLimit

RefundSurplus

Refund any surplus weight previously bought with BuyExecution.

Kind: Command

Errors: None.

SetErrorHandler(Xcm<()>)

Set the Error Handler Register. This is code that should be called in the case of an error happening.

An error occurring within execution of this code will NOT result in the error register being set, nor will an error handler be called due to it. The error handler and appendix may each still be set.

The apparent weight of this instruction is inclusive of the inner Xcm; the executing weight however includes only the difference between the previous handler and the new handler, which can reasonably be negative, which would result in a surplus.

Kind: Command

Errors: None.

SetAppendix(Xcm<()>)

Set the Appendix Register. This is code that should be called after code execution (including the error handler if any) is finished. This will be called regardless of whether an error occurred.

Any error occurring due to execution of this code will result in the error register being set, and the error handler (if set) firing.

The apparent weight of this instruction is inclusive of the inner Xcm; the executing weight however includes only the difference between the previous appendix and the new appendix, which can reasonably be negative, which would result in a surplus.

Kind: Command

Errors: None.

ClearError

Clear the Error Register.

Kind: Command

Errors: None.

SetAssetClaimer

Set asset claimer for all the trapped assets during the execution.

• location: The claimer of any assets potentially trapped during the execution of current XCM. It can be an arbitrary location, not necessarily the caller or origin.

Kind: Command

Errors: None.

Fields

location: Location

ClaimAsset

Create some assets which are being held on behalf of the origin.

• assets: The assets which are to be claimed. This must match exactly with the assets claimable by the origin of the ticket.
• ticket: The ticket of the asset; this is an abstract identifier to help locate the asset.

Kind: Command

Errors:

Fields

assets: Assets

ticket: Location

Trap(u64)

Always throws an error of type Trap.

Kind: Command

Errors:

• Trap: All circumstances, whose inner value is the same as this item’s inner value.

SubscribeVersion

Ask the destination system to respond with the most recent version of XCM that they support in a QueryResponse instruction. Any changes to this should also elicit similar responses when they happen.

• query_id: An identifier that will be replicated into the returned XCM message.
• max_response_weight: The maximum amount of weight that the QueryResponse item which is sent as a reply may take to execute. NOTE: If this is unexpectedly large then the response may not execute at all.

Kind: Command

Errors: Fallible

Fields

query_id: u64

max_response_weight: Weight

UnsubscribeVersion

Cancel the effect of a previous SubscribeVersion instruction.

Kind: Command

Errors: Fallible

BurnAsset(Assets)

Reduce Holding by up to the given assets.

Holding is reduced by as much as possible up to the assets in the parameter. It is not an error if the Holding does not contain the assets (to make this an error, use ExpectAsset prior).

Kind: Command

Errors: Infallible

ExpectAsset(Assets)

Throw an error if Holding does not contain at least the given assets.

Kind: Command

Errors:

• ExpectationFalse: If Holding Register does not contain the assets in the parameter.

ExpectOrigin(Option<Location>)

Ensure that the Origin Register equals some given value and throw an error if not.

Kind: Command

Errors:

• ExpectationFalse: If Origin Register is not equal to the parameter.

ExpectError(Option<(u32, Error)>)

Ensure that the Error Register equals some given value and throw an error if not.

Kind: Command

Errors:

• ExpectationFalse: If the value of the Error Register is not equal to the parameter.

ExpectTransactStatus(MaybeErrorCode)

Ensure that the Transact Status Register equals some given value and throw an error if not.

Kind: Command

Errors:

• ExpectationFalse: If the value of the Transact Status Register is not equal to the parameter.

QueryPallet

Query the existence of a particular pallet type.

• module_name: The module name of the pallet to query.
• response_info: Information for making the response.

Sends a QueryResponse to Origin whose data field PalletsInfo containing the information of all pallets on the local chain whose name is equal to name. This is empty in the case that the local chain is not based on Substrate Frame.

Safety: No concerns.

Kind: Command

Errors: Fallible.

Fields

module_name: Vec<u8>

response_info: QueryResponseInfo

ExpectPallet

Ensure that a particular pallet with a particular version exists.

• index: Compact: The index which identifies the pallet. An error if no pallet exists at this index.
• name: Vec<u8>: Name which must be equal to the name of the pallet.
• module_name: Vec<u8>: Module name which must be equal to the name of the module in which the pallet exists.
• crate_major: Compact: Version number which must be equal to the major version of the crate which implements the pallet.
• min_crate_minor: Compact: Version number which must be at most the minor version of the crate which implements the pallet.

Safety: No concerns.

Kind: Command

Errors:

• ExpectationFalse: In case any of the expectations are broken.

Fields

index: u32

name: Vec<u8>

module_name: Vec<u8>

crate_major: u32

min_crate_minor: u32

ReportTransactStatus(QueryResponseInfo)

Send a QueryResponse message containing the value of the Transact Status Register to some destination.

• query_response_info: The information needed for constructing and sending the QueryResponse message.

Safety: No concerns.

Kind: Command

Errors: Fallible.

ClearTransactStatus

Set the Transact Status Register to its default, cleared, value.

Safety: No concerns.

Kind: Command

Errors: Infallible.

UniversalOrigin(Junction)

Set the Origin Register to be some child of the Universal Ancestor.

Safety: Should only be usable if the Origin is trusted to represent the Universal Ancestor child in general. In general, no Origin should be able to represent the Universal Ancestor child which is the root of the local consensus system since it would by extension allow it to act as any location within the local consensus.

The Junction parameter should generally be a GlobalConsensus variant since it is only these which are children of the Universal Ancestor.

Kind: Command

Errors: Fallible.

ExportMessage

Send a message on to Non-Local Consensus system.

This will tend to utilize some extra-consensus mechanism, the obvious one being a bridge. A fee may be charged; this may be determined based on the contents of xcm. It will be taken from the Holding register.

• network: The remote consensus system to which the message should be exported.
• destination: The location relative to the remote consensus system to which the message should be sent on arrival.
• xcm: The message to be exported.

As an example, to export a message for execution on Statemine (parachain #1000 in the Kusama network), you would call with network: NetworkId::Kusama and destination: [Parachain(1000)].into(). Alternatively, to export a message for execution on Polkadot, you would call with network: NetworkId:: Polkadot and destination: Here.

Kind: Command

Errors: Fallible.

Fields

network: NetworkId

destination: Junctions

xcm: Xcm<()>

LockAsset

Lock the locally held asset and prevent further transfer or withdrawal.

This restriction may be removed by the UnlockAsset instruction being called with an Origin of unlocker and a target equal to the current Origin.

If the locking is successful, then a NoteUnlockable instruction is sent to unlocker.

• asset: The asset(s) which should be locked.
• unlocker: The value which the Origin must be for a corresponding UnlockAsset instruction to work.

Kind: Command.

Errors:

Fields

asset: Asset

unlocker: Location

UnlockAsset

Remove the lock over asset on this chain and (if nothing else is preventing it) allow the asset to be transferred.

• asset: The asset to be unlocked.
• target: The owner of the asset on the local chain.

Safety: No concerns.

Kind: Command.

Errors:

Fields

asset: Asset

target: Location

NoteUnlockable

Asset (asset) has been locked on the origin system and may not be transferred. It may only be unlocked with the receipt of the UnlockAsset instruction from this chain.

• asset: The asset(s) which are now unlockable from this origin.
• owner: The owner of the asset on the chain in which it was locked. This may be a location specific to the origin network.

Safety: origin must be trusted to have locked the corresponding asset prior as a consequence of sending this message.

Kind: Trusted Indication.

Errors:

Fields

asset: Asset

owner: Location

RequestUnlock

Send an UnlockAsset instruction to the locker for the given asset.

This may fail if the local system is making use of the fact that the asset is locked or, of course, if there is no record that the asset actually is locked.

• asset: The asset(s) to be unlocked.
• locker: The location from which a previous NoteUnlockable was sent and to which an UnlockAsset should be sent.

Kind: Command.

Errors:

Fields

asset: Asset

locker: Location

SetFeesMode

Sets the Fees Mode Register.

• jit_withdraw: The fees mode item; if set to true then fees for any instructions are withdrawn as needed using the same mechanism as WithdrawAssets.

Kind: Command.

Errors:

Fields

jit_withdraw: bool

SetTopic([u8; 32])

Set the Topic Register.

The 32-byte array identifier in the parameter is not guaranteed to be unique; if such a property is desired, it is up to the code author to enforce uniqueness.

Safety: No concerns.

Kind: Command

Errors:

ClearTopic

Clear the Topic Register.

Kind: Command

Errors: None.

AliasOrigin(Location)

Alter the current Origin to another given origin.

Kind: Command

Errors: If the existing state would not allow such a change.

UnpaidExecution

A directive to indicate that the origin expects free execution of the message.

At execution time, this instruction just does a check on the Origin register. However, at the barrier stage messages starting with this instruction can be disregarded if the origin is not acceptable for free execution or the weight_limit is Limited and insufficient.

Kind: Indication

Errors: If the given origin is Some and not equal to the current Origin register.

Fields

weight_limit: WeightLimit

check_origin: Option<Location>

PayFees

Pay Fees.

Successor to BuyExecution. Defined in fellowship RFC 105.

Fields

asset: Asset

InitiateTransfer

Initiates cross-chain transfer as follows:

Assets in the holding register are matched using the given list of AssetTransferFilters, they are then transferred based on their specified transfer type:

• teleport: burn local assets and append a ReceiveTeleportedAsset XCM instruction to the XCM program to be sent onward to the destination location,

• reserve deposit: place assets under the ownership of destination within this consensus system (i.e. its sovereign account), and append a ReserveAssetDeposited XCM instruction to the XCM program to be sent onward to the destination location,

• reserve withdraw: burn local assets and append a WithdrawAsset XCM instruction to the XCM program to be sent onward to the destination location,

The onward XCM is then appended a ClearOrigin to allow safe execution of any following custom XCM instructions provided in remote_xcm.

The onward XCM also contains either a PayFees or UnpaidExecution instruction based on the presence of the remote_fees parameter (see below).

If an XCM program requires going through multiple hops, it can compose this instruction to be used at every chain along the path, describing that specific leg of the flow.

Parameters:

• destination: The location of the program next hop.
• remote_fees: If set to Some(asset_xfer_filter), the single asset matching asset_xfer_filter in the holding register will be transferred first in the remote XCM program, followed by a PayFees(fee), then rest of transfers follow. This guarantees remote_xcm will successfully pass a AllowTopLevelPaidExecutionFrom barrier. If set to None, a UnpaidExecution instruction is appended instead. Please note that these assets are reserved for fees, they are sent to the fees register rather than holding. Best practice is to only add here enough to cover fees, and transfer the rest through the assets parameter.
• preserve_origin: Specifies whether the original origin should be preserved or cleared, using the instructions AliasOrigin or ClearOrigin respectively.
• assets: List of asset filters matched against existing assets in holding. These are transferred over to destination using the specified transfer type, and deposited to holding on destination.
• remote_xcm: Custom instructions that will be executed on the destination chain. Note that these instructions will be executed after a ClearOrigin so their origin will be None.

Safety: No concerns.

Kind: Command

Fields

destination: Location

remote_fees: Option<AssetTransferFilter>

preserve_origin: bool

assets: Vec<AssetTransferFilter>

remote_xcm: Xcm<()>

ExecuteWithOrigin

Executes inner xcm with origin set to the provided descendant_origin. Once the inner xcm is executed, the original origin (the one active for this instruction) is restored.

Parameters:

• descendant_origin: The origin that will be used during the execution of the inner xcm. If set to None, the inner xcm is executed with no origin. If set to Some(o), the inner xcm is executed as if there was a DescendOrigin(o) executed before it, and runs the inner xcm with origin: original_origin.append_with(o).
• xcm: Inner instructions that will be executed with the origin modified according to descendant_origin.

Safety: No concerns.

Kind: Command

Errors:

• BadOrigin

Fields

descendant_origin: Option<Junctions>

xcm: Xcm<()>