Module relay_chain

A module that re-exports relevant relay chain definitions.

Modules

runtime_api

Runtime API module declares the trait ParachainHost which is part of the Runtime API exposed from the Runtime to the Host.

v2

V2 primitives.

v9

V9 Primitives.

vstaging

Staging Primitives.

Structs

AbridgedHostConfiguration

Abridged version of HostConfiguration (from the Configuration parachains host runtime module) meant to be used by a parachain or PDK such as cumulus.

AbridgedHrmpChannel

Abridged version of HrmpChannel (from the Hrmp parachains host runtime module) meant to be used by a parachain or PDK such as cumulus.

ApprovalVote

A vote of approval on a candidate.

ApprovalVoteMultipleCandidates

A vote of approval for multiple candidates.

ApprovalVotingParams

Approval voting configuration parameters

AsyncBackingParams

Candidate’s acceptance limitations for asynchronous backing per relay parent.

AvailabilityBitfield

A bitfield concerning availability of backed candidates.

BackedCandidate

A backed (or backable, depending on context) candidate.

BlakeTwo256

Blake2-256 Hash implementation.

CandidateCommitments

Commitments made in a CandidateReceipt. Many of these are outputs of validation.

CandidateDescriptorV2

A unique descriptor of the candidate receipt.

CandidateHash

Unit type wrapper around Hash that represents a candidate hash.

CandidateReceiptV2

A candidate-receipt at version 2.

CheckedDisputeStatementSet

A checked set of dispute statements.

ChunkIndex

Index of an availability chunk.

ClaimQueueOffset

An offset in the relay chain claim queue.

CommittedCandidateReceiptV2

A candidate-receipt with commitments directly included.

CoreIndex

The unique (during session) index of a core.

CoreSelector

A strictly increasing sequence number, typically this would be the least significant byte of the block number.

DisputeState

The entire state of a dispute.

DisputeStatementSet

A set of statements about a specific candidate.

ExecutorParams

Deterministically serialized execution environment semantics

ExecutorParamsHash

Unit type wrapper around Hash that represents an execution parameter set hash.

ExecutorParamsPrepHash

Unit type wrapper around Hash that represents a hash of preparation-related executor parameters.

ExplicitDisputeStatement

An explicit statement on a candidate issued as part of a dispute.

GroupIndex

The unique (during session) index of a validator group.

GroupRotationInfo

A helper data-type for tracking validator-group rotations.

HeadData

Parachain head data included in the chain.

HrmpChannelId

A type that uniquely identifies an HRMP channel. An HRMP channel is established between two paras. In text, we use the notation (A, B) to specify a channel between A and B. The channels are unidirectional, meaning that (A, B) and (B, A) refer to different channels. The convention is that we use the first item tuple for the sender and the second for the recipient. Only one channel is allowed between two participants in one direction, i.e. there cannot be 2 different channels identified by (A, B). A channel with the same para id in sender and recipient is invalid. That is, however, not enforced.

Id

Unique identifier of a parachain.

InboundDownwardMessage

A wrapped version of DownwardMessage. The difference is that it has attached the block number when the message was sent.

InboundHrmpMessage

An HRMP message seen from the perspective of a recipient.

IndexedVec

IndexedVec struct indexed by type specific indices.

InherentData

Parachains inherent-data passed into the runtime by a block author

InternalVersion

A type representing the version of the candidate descriptor and internal version number.

OccupiedCore

Information about a core which is currently occupied.

OutboundHrmpMessage

An HRMP message seen from the perspective of a sender.

ParathreadClaim

A claim on authoring the next block for a given parathread (on-demand parachain).

ParathreadEntry

An entry tracking a claim to ensure it does not pass the maximum number of retries.

PersistedValidationData

The validation data provides information about how to create the inputs for validation of a candidate. This information is derived from the chain state and will vary from para to para, although some fields may be the same for every para.

PvfCheckStatement

A statement from the specified validator whether the given validation code passes PVF pre-checking or not anchored to the given session index.

RuntimeMetricLabel

A metric label.

RuntimeMetricLabels

A set of metric labels.

RuntimeMetricUpdate

Runtime metric update event.

ScheduledCore

Information about a core which is currently occupied.

SchedulerParams

Scheduler configuration parameters. All coretime/ondemand parameters are here.

ScrapedOnChainVotes

Scraped runtime backing votes and resolved disputes.

SessionInfo

Information about validator sets of a session.

Signed

Signed data with signature already verified.

SigningContext

A type returned by runtime with current session index and a parent hash.

Slot

Unit type wrapper that represents a slot.

UncheckedExtrinsic

Simple blob to hold an extrinsic without committing to its format and ensure it is serialized correctly.

UncheckedSigned

Unchecked signed data, can be converted to Signed by checking the signature.

ValidationCode

Parachain validation code.

ValidationCodeHash

Unit type wrapper around Hash that represents the blake2-256 hash of validation code in particular.

ValidatorIndex

Index of the validator is used as a lightweight replacement of the ValidatorId when appropriate.

Enums

CandidateDescriptorVersion

A type representing the version of the candidate descriptor.

CandidateEvent

An event concerning a candidate.

CommittedCandidateReceiptError

CommittedCandidateReceiptError construction errors.

CompactStatement

Statements that can be made about parachain candidates. These are the actual values that are signed.

ConsensusLog

A consensus log item for polkadot validation. To be used with POLKADOT_ENGINE_ID.

CoreState

The state of a particular availability core.

DisputeOffenceKind

Supercedes the old ‘SlashingOffenceKind’ enum.

DisputeStatement

A statement about a candidate, to be used within the dispute resolution process.

ExecutorParam

The different executor parameters for changing the execution environment semantics.

ExecutorParamError

Possible inconsistencies of executor params.

InvalidDisputeStatementKind

Different kinds of statements of invalidity on a candidate.

OccupiedCoreAssumption

An assumption being made about the state of an occupied core.

PvfExecKind

Type discriminator for PVF execution.

PvfPrepKind

Type discriminator for PVF preparation.

RuntimeMetricOp

Runtime metric operations.

UMPSignal

Signals that a parachain can send to the relay chain via the UMP queue.

UpgradeGoAhead

A struct that the relay-chain communicates to a parachain indicating what course of action the parachain should take in the coordinated parachain validation code upgrade process.

UpgradeRestriction

A possible upgrade restriction that prevents a parachain from performing an upgrade.

ValidDisputeStatementKind

Different kinds of statements of validity on a candidate.

ValidityAttestation

An either implicit or explicit attestation to the validity of a parachain candidate.

ValidityError

Custom validity errors used in Polkadot while validating transactions.

Constants

ASSIGNMENT_KEY_TYPE_ID

The key type ID for parachain assignment key.

DEFAULT_CLAIM_QUEUE_OFFSET

The default claim queue offset to be used if it’s not configured/accessible in the parachain runtime

DEFAULT_SCHEDULING_LOOKAHEAD

Default value for SchedulerParams.lookahead

LEGACY_MIN_BACKING_VOTES

Backing votes threshold used from the host prior to runtime API version 6 and from the runtime prior to v9 configuration migration.

LOWEST_PUBLIC_ID

The ID of the first publicly registrable parachain.

MAX_CODE_SIZE

Maximum compressed code size we support right now. At the moment we have runtime upgrade on chain, which restricts scalability severely. If we want to have bigger values, we should fix that first.

MAX_HEAD_DATA_SIZE

Maximum head data size we support right now.

MAX_POV_SIZE

Maximum PoV size we support right now.

MIN_CODE_SIZE

Compressed or not the wasm blob can never be less than 9 bytes.

ON_DEMAND_DEFAULT_QUEUE_MAX_SIZE

Default queue size we use for the on-demand order book.

ON_DEMAND_MAX_QUEUE_MAX_SIZE

Maximum for maximum queue size.

PARACHAINS_INHERENT_IDENTIFIER

Unique identifier for the Parachains Inherent

PARACHAIN_KEY_TYPE_ID

The key type ID for a parachain validator key.

UMP_SEPARATOR

Separator between XCM and UMPSignal.

Traits

AppVerify

Means of signature verification of an application key.

EncodeAs

This helper trait ensures that we can encode Statement as CompactStatement, and anything as itself.

HashT

Abstraction around hashing

MutateDescriptorV2

A trait to allow changing the descriptor field values in tests.

Functions

byzantine_threshold

The maximum number of validators f which may safely be faulty.

check_candidate_backing

Verify the backing of the given candidate.

effective_minimum_backing_votes

Adjust the configured needed backing votes with the size of the backing group.

skip_ump_signals

Utility function for skipping the ump signals.

supermajority_threshold

The supermajority threshold of validators which represents a subset guaranteed to have at least f+1 honest validators.

transpose_claim_queue

Returns a mapping between the para id and the core indices assigned at different depths in the claim queue.

Type Aliases

AccountId

Alias to the opaque account ID type for this chain, actually a AccountId32. This is always 32 bytes.

AccountIndex

The type for looking up accounts. We don’t expect more than 4 billion of them.

AccountPublic

Alias to the public key used for this chain, actually a MultiSigner. Like the signature, this also isn’t a fixed size when encoded, as different cryptos have different size public keys.

ApprovedPeerId

Approved PeerId type. PeerIds in polkadot should typically be 32 bytes long but for identity multihash can go up to 64. Cannot reuse the PeerId type definition from the networking code as it’s too generic and extensible.

AssignmentId

The public key of a keypair used by a validator for determining assignments to approve included parachain candidates.

AssignmentPair

The full keypair used by a validator for determining assignments to approve included parachain candidates.

AuthorityDiscoveryId

An authority discovery authority identifier.

Balance

The balance of an account. 128-bits (or 38 significant decimal figures) will allow for 10 m currency (10^7) at a resolution to all for one second’s worth of an annualised 50% reward be paid to a unit holder (10^11 unit denomination), or 10^18 total atomic units, to grow at 50%/year for 51 years (10^9 multiplier) for an eventual total of 10^27 units (27 significant decimal figures). We round denomination to 10^12 (12 SDF), and leave the other redundancy at the upper end so that 32 bits may be multiplied with a balance in 128 bits without worrying about overflow.

Block

Block type.

BlockId

Block ID.

BlockNumber

The block number type used by Polkadot. 32-bits will allow for 136 years of blocks assuming 1 block per second.

CandidateIndex

The index of the candidate in the list of candidates fully included as-of the block.

ChainId

Identifier for a chain. 32-bit should be plenty.

CheckedMultiDisputeStatementSet

A set of checked dispute statements.

CollatorId

Identity that collators use.

CollatorPair

A Parachain collator keypair.

CollatorSignature

Signature on candidate’s block data by a collator.

DownwardMessage

A message sent from the relay-chain down to a parachain.

Hash

A hash of some data used by the relay chain.

Header

Header type.

HorizontalMessages

Moment

An instant or duration in time.

MultiDisputeStatementSet

A set of dispute statements.

NodeFeatures

Bit indices in the HostConfiguration.node_features that correspond to different node features.

Nonce

Index of a transaction in the relay chain. 32-bit should be plenty.

Remark

The information that goes alongside a transfer_into_parachain operation. Entirely opaque, it will generally be used for identifying the reason for the transfer. Typically it will hold the destination account to which the transfer should be credited. If still more information is needed, then this should be a hash with the pre-image presented via an off-chain mechanism on the parachain.

RuntimeMetricLabelValue

A metric label value.

RuntimeMetricLabelValues

A set of metric label values.

SessionIndex

Simple index type with which we can count sessions.

Signature

Alias to type for a signature for a transaction on the relay chain. This allows one of several kinds of underlying crypto to be used, so isn’t a fixed size when encoded.

SignedAvailabilityBitfield

A bitfield signed by a particular validator about the availability of pending candidates.

SignedAvailabilityBitfields

A set of signed availability bitfields. Should be sorted by validator index, ascending.

SignedStatement

A signed compact statement, suitable to be sent to the chain.

TransposedClaimQueue

The claim queue mapped by parachain id.

UncheckedSignedAvailabilityBitfield

A signed bitfield with signature not yet checked.

UncheckedSignedAvailabilityBitfields

A set of unchecked signed availability bitfields. Should be sorted by validator index, ascending.

UncheckedSignedStatement

A signed compact statement, with signature not yet checked.

UpwardMessage

A message from a parachain to its Relay Chain.

ValidatorId

Identity that parachain validators use when signing validation messages.

ValidatorPair

A Parachain validator keypair.

ValidatorSignature

Signature with which parachain validators sign blocks.