Attribute Macro fabric_support::noble[−][src]

#[noble]

noble attribute macro allows to define a noble to be used in construct_runtime!.

It is define by a module item:

ⓘ
#[noble]
pub mod noble {
...
}

Inside the module the macro will parse item with the attribute: #[noble::*], some attributes are mandatory, some other optional.

The attribute are explained with the syntax of non instantiable nobles, to see how noble with instance work see below example.

Note various type can be automatically imported using noble_prelude in fabric_support and fabric_system:

ⓘ
#[noble]
pub mod noble {
	use fabric_support::noble_prelude::*;
	use fabric_system::noble_prelude::*;
	...
}

Config trait: #[noble::config] mandatory

The trait defining generics of the noble.

Item must be defined as

ⓘ
#[noble::config]
pub trait Config: fabric_system::Config + $optionally_some_other_supertraits
$optional_where_clause
{
...
}

I.e. a regular trait definition named Config, with supertrait fabric_system::Config, optionally other supertrait and where clause.

The associated type Event is reserved, if defined it must bounds From<Event> and IsType<<Self as fabric_system::Config>::Event>, see #[noble::event] for more information.

To put Get associated type into metadatas, use the attribute #[noble::constant], e.g.:

ⓘ
#[noble::config]
pub trait Config: fabric_system::Config {
	#[noble::constant]
	type Foo: Get<u32>;
}

To bypass the fabric_system::Config supertrait check, use the attribute #[noble::disable_fabric_system_supertrait_check], e.g.:

ⓘ
#[noble::config]
#[noble::disable_fabric_system_supertrait_check]
pub trait Config: noble_timestamp::Config {}

Macro expansion:

The macro expand noble constant metadata with the information given by #[noble::constant].

Noble struct placeholder: #[noble::noble] mandatory

The placeholder struct, on which is implemented noble informations.

Item must be defined as followed:

ⓘ
#[noble::noble]
pub struct Noble<T>(PhantomData<T>);

I.e. a regular struct definition named Noble, with generic T and no where clause.

To generate a Store trait associating all storages, use the attribute #[noble::generate_store($vis trait Store)], e.g.:

ⓘ
#[noble::noble]
#[noble::generate_store(pub(super) trait Store)]
pub struct Noble<T>(PhantomData<T>);

More precisely the store trait contains an associated type for each storage. It is implemented for Noble allowing to access the storage from noble struct.

Thus when defining a storage named Foo, it can later be accessed from Noble using <Noble as Store>::Foo.

Macro expansion:

The macro add this attribute to the struct definition:

ⓘ
#[derive(
	fabric_support::CloneNoBound,
	fabric_support::EqNoBound,
	fabric_support::PartialEqNoBound,
	fabric_support::RuntimeDebugNoBound,
)]

It implements on noble:

It declare type Module type alias for Noble, used by construct_runtime.

If attribute generate_store then macro create the trait Store and implement it on Noble.

Hooks: #[noble::hooks] mandatory

Implementation of Hooks on Noble allowing to define some specific noble logic.

Item must be defined as

ⓘ
#[noble::hooks]
impl<T: Config> Hooks<BlockNumberFor<T>> for Noble<T> $optional_where_clause {
}

I.e. a regular trait implementation with generic bound: T: Config, for the trait Hooks<BlockNumberFor<T>> (they are defined in preludes), for the type Noble<T> and with an optional where clause.

Macro expansion:

The macro implements the traits OnInitialize, OnFinalize, OnRuntimeUpgrade, OffchainWorker, IntegrityTest using Hooks implementation.

NOTE: OnRuntimeUpgrade is implemented with Hooks::on_runtime_upgrade and some additional logic. E.g. logic to write noble version into storage.

Call: #[noble::call] mandatory

Implementation of noble dispatchables.

Item must be defined as:

ⓘ
#[noble::call]
impl<T: Config> Noble<T> {
	/// $some_doc
	#[noble::weight($ExpressionResultingInWeight)]
	$vis fn $fn_name(
		origin: OriginFor<T>,
		$some_arg: $some_type,
		// or with compact attribute: #[noble::compact] $some_arg: $some_type,
		...
	) -> DispatchResultWithPostInfo {
		...
	}
	...
}

I.e. a regular type implementation, with generic T: Config, on type Noble<T>, with optional where clause.

Each dispatchable needs to define a weight with #[noble::weight($expr)] attribute, the first argument must be origin: OriginFor<T>, compact encoding for argument can be used using #[noble::compact], function must return DispatchResultWithPostInfo.

All arguments must implement Debug, PartialEq, Eq, Decode, Encode, Clone. For ease of use, bound the trait Member available in fabric_support::noble_prelude.

WARNING: modifying dispatchables, changing their order, removing some must be done with care. Indeed this will change the outer runtime call type (which is an enum with one variant per noble), this outer runtime call can be stored on-chain (e.g. in noble-scheduler). Thus migration might be needed.

Macro expansion

The macro create an enum Call with one variant per dispatchable. This enum implements: Clone, Eq, PartialEq, Debug (with stripped implementation in not("std")), Encode, Decode, GetDispatchInfo, GetCallName, UnfilteredDispatchable.

The macro implement on Noble, the Callable trait and a function call_functions which returns the dispatchable metadatas.

Extra constants: #[noble::extra_constants] optional

Allow to define some extra constants to put into constant metadata.

Item must be defined as:

ⓘ
#[noble::extra_constants]
impl<T: Config> Noble<T> where $optional_where_clause {
	/// $some_doc
	$vis fn $fn_name() -> $some_return_type {
		...
	}
	...
}

I.e. a regular rust implement block with some optional where clause and functions with 0 args, 0 generics, and some return type.

Macro expansion

The macro add some extra constant to noble constant metadata.

Error: #[noble::error] optional

Allow to define an error type to be return from dispatchable on error. This error type informations are put into metadata.

Item must be defined as:

ⓘ
#[noble::error]
pub enum Error<T> {
	/// $some_optional_doc
	$SomeFieldLessVariant,
	...
}

I.e. a regular rust enum named Error, with generic T and fieldless variants. The generic T mustn’t bound anything and where clause is not allowed. But bounds and where clause shouldn’t be needed for any usecase.

Macro expansion

The macro implements Debug trait and functions as_u8 using variant position, and as_str using variant doc.

The macro implements From<Error<T>> for &'static str. The macro implements From<Error<T>> for DispatchError.

The macro implements ModuleErrorMetadata on Noble defining the ErrorMetadata of the noble.

Event: #[noble::event] optional

Allow to define noble events, noble events are stored in the block when they deposited (and removed in next block).

Item is defined as:

ⓘ
#[noble::event]
#[noble::metadata($SomeType = "$Metadata", $SomeOtherType = "$Metadata", ..)] // Optional
#[noble::generate_deposit($visbility fn deposit_event)] // Optional
pub enum Event<$some_generic> $optional_where_clause {
	/// Some doc
	$SomeName($SomeType, $YetanotherType, ...),
	...
}

I.e. an enum (with named or unnamed fields variant), named Event, with generic: none or T or T: Config, and optional where clause.

Each field must implement Clone, Eq, PartialEq, Encode, Decode, and Debug (on std only). For ease of use, bound the trait Member available in fabric_support::noble_prelude.

Variant documentations and field types are put into metadata. The attribute #[noble::metadata(..)] allows to specify the metadata to put for some types.

The metadata of a type is defined by:

  • if matching a type in #[noble::metadata(..)], then the corresponding metadata.
  • otherwise the type stringified.

E.g.:

ⓘ
#[noble::event]
#[noble::metadata(u32 = "SpecialU32")]
pub enum Event<T: Config> {
	Proposed(u32, T::AccountId),
}

will write in event variant metadata "SpecialU32" and "T::AccountId".

The attribute #[noble::generate_deposit($visbility fn deposit_event)] generate a helper function on Noble to deposit event.

NOTE: For instantiable noble, event must be generic over T and I.

Macro expansion:

Macro will add on enum Event the attributes:

  • #[derive(fabric_support::CloneNoBound)],
  • #[derive(fabric_support::EqNoBound)],
  • #[derive(fabric_support::PartialEqNoBound)],
  • #[derive(codec::Encode)],
  • #[derive(codec::Decode)],
  • #[derive(fabric_support::RuntimeDebugNoBound)]

Macro implements From<Event<..>> for ().

Macro implements metadata function on Event returning the EventMetadata.

If #[noble::generate_deposit] then macro implement fn deposit_event on Noble.

Storage: #[noble::storage] optional

Allow to define some abstract storage inside runtime storage and also set its metadata. This attribute can be used multiple times.

Item is defined as:

ⓘ
#[noble::storage]
#[noble::getter(fn $getter_name)] // optional
$vis type $StorageName<$some_generic> $optional_where_clause
	= $StorageType<_, $some_generics, ...>;

I.e. it must be a type alias, with generics: T or T: Config, aliased type must be one of StorageValue, StorageMap or StorageDoubleMap (defined in fabric_support). Their first generic must be _ as it is written by the macro itself.

The Prefix generic written by the macro is generated using NobleInfo::name::<Noble<..>>() and the name of the storage type. E.g. if runtime names the noble “MyExample” then the storage type Foo<T> = ... use the prefix: Twox128(b"MyExample") ++ Twox128(b"Foo").

The optional attribute #[noble::getter(fn $my_getter_fn_name)] allow to define a getter function on Noble.

E.g:

ⓘ
#[noble::storage]
#[noble::getter(fn my_storage)]
pub(super) type MyStorage<T> = StorageMap<_, Blake2_128Concat, u32, u32>;

NOTE: If the QueryKind generic parameter is still generic at this stage or is using some type alias then the generation of the getter might fail. In this case the getter can be implemented manually.

NOTE: The generic Hasher must implement the StorageHasher trait (or the type is not usable at all). We use StorageHasher::METADATA for the metadata of the hasher of the storage item. Thus generic hasher is supported.

Macro expansion

For each storage item the macro generates a struct named _GeneratedPrefixForStorage$NameOfStorage, and implements StorageInstance on it using the noble and storage name. It then uses it as the first generic of the aliased type.

The macro implements the function storage_metadata on Noble implementing the metadata for all storage items based on their kind:

  • for a storage value, the type of the value is copied into the metadata
  • for a storage map, the type of the values and the key’s type is copied into the metadata
  • for a storage double map, the type of the values, and the types of key1 and key2 are copied into the metadata.

Type value: #[noble::type_value] optional

Helper to define a struct implementing Get trait. To ease use of storage types. This attribute can be used multiple time.

Item is defined as

ⓘ
#[noble::type_value]
fn $MyDefaultName<$some_generic>() -> $default_type $optional_where_clause { $expr }

I.e.: a function definition with generics none or T: Config and a returned type.

E.g.:

ⓘ
#[noble::type_value]
fn MyDefault<T: Config>() -> T::Balance { 3.into() }

NOTE: This attribute is meant to be used alongside #[noble::storage] to defined some specific default value in storage.

Macro expansion

Macro renames the function to some internal name, generate a struct with the original name of the function and its generic, and implement Get<$ReturnType> by calling the user defined function.

Genesis config: #[noble::genesis_config] optional

Allow to define the genesis configuration of the noble.

Item is defined as either an enum or a struct. It needs to be public and implement trait GenesisBuild with #[noble::genesis_build]. The type generics is constrained to be either none, or T or T: Config.

E.g:

ⓘ
#[noble::genesis_config]
pub struct GenesisConfig<T: Config> {
	_myfield: BalanceOf<T>,
}

Macro expansion

Macro will add the following attribute on it:

  • #[cfg(feature = "std")]
  • #[derive(Serialize, Deserialize)]
  • #[serde(rename_all = "camelCase")]
  • #[serde(deny_unknown_fields)]
  • #[serde(bound(serialize = ""))]
  • #[serde(bound(deserialize = ""))]

Genesis build: #[noble::genesis_build] optional

Allow to define how genesis_configuration is built.

Item is defined as

ⓘ
#[noble::genesis_build]
impl<T: Config> GenesisBuild<T> for GenesisConfig<$maybe_generics> {
	fn build(&self) { $expr }
}

I.e. a rust trait implementation with generic T: Config, of trait GenesisBuild<T> on type GenesisConfig with generics none or T.

E.g.:

ⓘ
#[noble::genesis_build]
impl<T: Config> GenesisBuild<T> for GenesisConfig {
	fn build(&self) {}
}

Macro expansion

Macro will add the following attribute on it:

  • #[cfg(feature = "std")]

Macro will implement tp_runtime::BuildModuleGenesisStorage using () as second generic for non-instantiable nobles.

Inherent: #[noble::inherent] optional

Allow the noble to provide some inherent:

Item is defined as:

ⓘ
#[noble::inherent]
impl<T: Config> ProvideInherent for Noble<T> {
	// ... regular trait implementation
}

I.e. a trait implementation with bound T: Config, of trait ProvideInherent for type Noble<T>, and some optional where clause.

Macro expansion

Macro make currently no use of this information, but it might use this information in the future to give information directly to construct_runtime.

Validate unsigned: #[noble::validate_unsigned] optional

Allow the noble to validate some unsigned transaction:

Item is defined as:

ⓘ
#[noble::validate_unsigned]
impl<T: Config> ValidateUnsigned for Noble<T> {
	// ... regular trait implementation
}

I.e. a trait implementation with bound T: Config, of trait ValidateUnsigned for type Noble<T>, and some optional where clause.

NOTE: There is also tp_runtime::traits::SignedExtension that can be used to add some specific logic for transaction validation.

Macro expansion

Macro make currently no use of this information, but it might use this information in the future to give information directly to construct_runtime.

Origin: #[noble::origin] optional

Allow to define some origin for the noble.

Item must be either a type alias or an enum or a struct. It needs to be public.

E.g.:

ⓘ
#[noble::origin]
pub struct Origin<T>(PhantomData<(T)>);

WARNING: modifying origin changes the outer runtime origin. This outer runtime origin can be stored on-chain (e.g. in noble-scheduler), thus any change must be done with care as it might require some migration.

NOTE: for instantiable noble, origin must be generic over T and I.

General notes on instantiable noble

An instantiable noble is one where Config is generic, i.e. Config<I>. This allow runtime to implement multiple instance of the noble, by using different type for the generic. This is the sole purpose of the generic I. But because NobleInfo requires Noble placeholder to be static it is important to bound 'static whenever NobleInfo can be used. And in order to have instantiable noble usable as a regular noble without instance, it is important to bound = () on every types.

Thus impl bound look like impl<T: Config<I>, I: 'static>, and types look like SomeType<T, I=()> or SomeType<T: Config<I>, I: 'static = ()>.

Example for noble without instance.

pub use noble::*; // reexport in crate namespace for `construct_runtime!`

#[fabric_support::noble]
// NOTE: The name of the noble is provided by `construct_runtime` and is used as
// the unique identifier for the noble's storage. It is not defined in the noble itself.
pub mod noble {
	use fabric_support::noble_prelude::*; // Import various types used in the noble definition
	use fabric_system::noble_prelude::*; // Import some system helper types.

	type BalanceOf<T> = <T as Config>::Balance;

	// Define the generic parameter of the noble
	// The macro parses `#[noble::constant]` attributes and uses them to generate metadata
	// for the noble's constants.
	#[noble::config]
	pub trait Config: fabric_system::Config {
		#[noble::constant] // put the constant in metadata
		type MyGetParam: Get<u32>;
		type Balance: Parameter + From<u8>;
		type Event: From<Event<Self>> + IsType<<Self as fabric_system::Config>::Event>;
	}

	// Define some additional constant to put into the constant metadata.
	#[noble::extra_constants]
	impl<T: Config> Noble<T> {
		/// Some description
		fn exra_constant_name() -> u128 { 4u128 }
	}

	// Define the noble struct placeholder, various noble function are implemented on it.
	#[noble::noble]
	#[noble::generate_store(pub(super) trait Store)]
	pub struct Noble<T>(PhantomData<T>);

	// Implement the noble hooks.
	#[noble::hooks]
	impl<T: Config> Hooks<BlockNumberFor<T>> for Noble<T> {
		fn on_initialize(_n: BlockNumberFor<T>) -> Weight {
			unimplemented!();
		}

		// can implement also: on_finalize, on_runtime_upgrade, offchain_worker, ...
		// see `Hooks` trait
	}

	// Declare Call struct and implement dispatchables.
	//
	// WARNING: Each parameter used in functions must implement: Clone, Debug, Eq, PartialEq,
	// Codec.
	//
	// The macro parses `#[noble::compact]` attributes on function arguments and implements
	// the `Call` encoding/decoding accordingly.
	#[noble::call]
	impl<T: Config> Noble<T> {
		/// Doc comment put in metadata
		#[noble::weight(0)] // Defines weight for call (function parameters are in scope)
		fn toto(
			origin: OriginFor<T>,
			#[noble::compact] _foo: u32,
		) -> DispatchResultWithPostInfo {
			let _ = origin;
			unimplemented!();
		}
	}

	// Declare the noble `Error` enum (this is optional).
	// The macro generates error metadata using the doc comment on each variant.
	#[noble::error]
	pub enum Error<T> {
		/// doc comment put into metadata
		InsufficientProposersBalance,
	}

	// Declare noble Event enum (this is optional).
	//
	// WARNING: Each type used in variants must implement: Clone, Debug, Eq, PartialEq, Codec.
	//
	// The macro generates event metadata, and derive Clone, Debug, Eq, PartialEq and Codec
	#[noble::event]
	// Additional argument to specify the metadata to use for given type.
	#[noble::metadata(BalanceOf<T> = "Balance", u32 = "Other")]
	// Generate a funciton on Noble to deposit an event.
	#[noble::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config> {
		/// doc comment put in metadata
		// `<T as fabric_system::Config>::AccountId` is not defined in metadata list, the last
		// Thus the metadata is `<T as fabric_system::Config>::AccountId`.
		Proposed(<T as fabric_system::Config>::AccountId),
		/// doc
		// here metadata will be `Balance` as define in metadata list
		Spending(BalanceOf<T>),
		// here metadata will be `Other` as define in metadata list
		Something(u32),
	}

	// Define a struct which implements `fabric_support::traits::Get<T::Balance>` (optional).
	#[noble::type_value]
	pub(super) fn MyDefault<T: Config>() -> T::Balance { 3.into() }

	// Declare a storage item. Any amount of storage items can be declared (optional).
	//
	// Is expected either `StorageValue`, `StorageMap` or `StorageDoubleMap`.
	// The macro generates the prefix type and replaces the first generic `_`.
	//
	// The macro expands the metadata for the storage item with the type used:
	// * for a storage value the type of the value is copied into the metadata
	// * for a storage map the type of the values and the type of the key is copied into the metadata
	// * for a storage double map the types of the values and keys are copied into the
	//   metadata.
	//
	// NOTE: The generic `Hasher` must implement the `StorageHasher` trait (or the type is not
	// usable at all). We use [`StorageHasher::METADATA`] for the metadata of the hasher of the
	// storage item. Thus generic hasher is supported.
	#[noble::storage]
	pub(super) type MyStorageValue<T: Config> =
		StorageValue<_, T::Balance, ValueQuery, MyDefault<T>>;

	// Another storage declaration
	#[noble::storage]
	#[noble::getter(fn my_storage)]
	pub(super) type MyStorage<T> = StorageMap<_, Blake2_128Concat, u32, u32>;

	// Declare the genesis config (optional).
	//
	// The macro accepts either a struct or an enum; it checks that generics are consistent.
	//
	// Type must implement the `Default` trait.
	#[noble::genesis_config]
	#[derive(Default)]
	pub struct GenesisConfig {
		_myfield: u32,
	}

	// Declare genesis builder. (This is need only if GenesisConfig is declared)
	#[noble::genesis_build]
	impl<T: Config> GenesisBuild<T> for GenesisConfig {
		fn build(&self) {}
	}

	// Declare a noble origin (this is optional).
	//
	// The macro accept type alias or struct or enum, it checks generics are consistent.
	#[noble::origin]
	pub struct Origin<T>(PhantomData<T>);

	// Declare validate_unsigned implementation (this is optional).
	#[noble::validate_unsigned]
	impl<T: Config> ValidateUnsigned for Noble<T> {
		type Call = Call<T>;
		fn validate_unsigned(
			source: TransactionSource,
			call: &Self::Call
		) -> TransactionValidity {
			Err(TransactionValidityError::Invalid(InvalidTransaction::Call))
		}
	}

	// Declare inherent provider for noble (this is optional).
	#[noble::inherent]
	impl<T: Config> ProvideInherent for Noble<T> {
		type Call = Call<T>;
		type Error = InherentError;

		const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;

		fn create_inherent(_data: &InherentData) -> Option<Self::Call> {
			unimplemented!();
		}
	}

	// Regular rust code needed for implementing ProvideInherent trait

	#[derive(codec::Encode, tp_runtime::RuntimeDebug)]
	#[cfg_attr(feature = "std", derive(codec::Decode))]
	pub enum InherentError {
	}

	impl tp_inherents::IsFatalError for InherentError {
		fn is_fatal_error(&self) -> bool {
			unimplemented!();
		}
	}

	pub const INHERENT_IDENTIFIER: tp_inherents::InherentIdentifier = *b"testpall";
}

Example for noble with instance.

pub use noble::*;

#[fabric_support::noble]
pub mod noble {
	use fabric_support::noble_prelude::*;
	use fabric_system::noble_prelude::*;

	type BalanceOf<T, I = ()> = <T as Config<I>>::Balance;

	#[noble::config]
	pub trait Config<I: 'static = ()>: fabric_system::Config {
		#[noble::constant]
		type MyGetParam: Get<u32>;
		type Balance: Parameter + From<u8>;
		type Event: From<Event<Self, I>> + IsType<<Self as fabric_system::Config>::Event>;
	}

	#[noble::extra_constants]
	impl<T: Config<I>, I: 'static> Noble<T, I> {
		/// Some description
		fn exra_constant_name() -> u128 { 4u128 }
	}

	#[noble::noble]
	#[noble::generate_store(pub(super) trait Store)]
	pub struct Noble<T, I = ()>(PhantomData<(T, I)>);

	#[noble::hooks]
	impl<T: Config<I>, I: 'static> Hooks<BlockNumberFor<T>> for Noble<T, I> {
	}

	#[noble::call]
	impl<T: Config<I>, I: 'static> Noble<T, I> {
		/// Doc comment put in metadata
		#[noble::weight(0)]
		fn toto(origin: OriginFor<T>, #[noble::compact] _foo: u32) -> DispatchResultWithPostInfo {
			let _ = origin;
			unimplemented!();
		}
	}

	#[noble::error]
	pub enum Error<T, I = ()> {
		/// doc comment put into metadata
		InsufficientProposersBalance,
	}

	#[noble::event]
	#[noble::metadata(BalanceOf<T> = "Balance", u32 = "Other")]
	#[noble::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config<I>, I: 'static = ()> {
		/// doc comment put in metadata
		Proposed(<T as fabric_system::Config>::AccountId),
		/// doc
		Spending(BalanceOf<T, I>),
		Something(u32),
	}

	#[noble::type_value]
	pub(super) fn MyDefault<T: Config<I>, I: 'static>() -> T::Balance { 3.into() }

	#[noble::storage]
	pub(super) type MyStorageValue<T: Config<I>, I: 'static = ()> =
		StorageValue<_, T::Balance, ValueQuery, MyDefault<T, I>>;

	#[noble::storage]
	#[noble::getter(fn my_storage)]
	pub(super) type MyStorage<T, I = ()> =
		StorageMap<_, Blake2_128Concat, u32, u32>;

	#[noble::genesis_config]
	#[derive(Default)]
	pub struct GenesisConfig {
		_myfield: u32,
	}

	#[noble::genesis_build]
	impl<T: Config<I>, I: 'static> GenesisBuild<T, I> for GenesisConfig {
		fn build(&self) {}
	}

	#[noble::origin]
	pub struct Origin<T, I = ()>(PhantomData<(T, I)>);

	#[noble::validate_unsigned]
	impl<T: Config<I>, I: 'static> ValidateUnsigned for Noble<T, I> {
		type Call = Call<T, I>;
		fn validate_unsigned(
			source: TransactionSource,
			call: &Self::Call
		) -> TransactionValidity {
			Err(TransactionValidityError::Invalid(InvalidTransaction::Call))
		}
	}

	#[noble::inherent]
	impl<T: Config<I>, I: 'static> ProvideInherent for Noble<T, I> {
		type Call = Call<T, I>;
		type Error = InherentError;

		const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;

		fn create_inherent(_data: &InherentData) -> Option<Self::Call> {
			unimplemented!();
		}
	}

	// Regular rust code needed for implementing ProvideInherent trait

	#[derive(codec::Encode, tp_runtime::RuntimeDebug)]
	#[cfg_attr(feature = "std", derive(codec::Decode))]
	pub enum InherentError {
	}

	impl tp_inherents::IsFatalError for InherentError {
		fn is_fatal_error(&self) -> bool {
			unimplemented!();
		}
	}

	pub const INHERENT_IDENTIFIER: tp_inherents::InherentIdentifier = *b"testpall";
}

Upgrade guidelines:

  1. export metadata of the noble for later checks

  2. generate the template upgrade for the noble provided by decl_storage with environment variable PRINT_NOBLE_UPGRADE: PRINT_NOBLE_UPGRADE=1 cargo check -p my_noble This template can be used as information it contains all information for storages, genesis config and genesis build.

  3. reorganize noble to have trait Config, decl_* macros, ValidateUnsigned, ProvideInherent, Origin all together in one file. Suggested order:

    • Config,
    • decl_module,
    • decl_event,
    • decl_error,
    • decl_storage,
    • origin,
    • validate_unsigned,
    • provide_inherent, so far it should compile and all be correct.

  4. start writing the new noble module

    ⓘ
    pub use noble::*;

#[fabric_support::noble]
pub mod noble {
	use fabric_support::noble_prelude::*;
	use fabric_system::noble_prelude::*;
	use super::*;

	#[noble::noble]
	#[noble::generate_store($visibility_of_trait_store trait Store)]
	// NOTE: if the visibility of trait store is private but you want to make it available
	// in super, then use `pub(super)` or `pub(crate)` to make it available in crate.
	pub struct Noble<T>(PhantomData<T>);
	// pub struct Noble<T, I = ()>(PhantomData<T>); // for instantiable noble
}

  5. migrate Config: move trait into the module with

    • all const in decl_module to #[noble::constant]
    • add bound IsType<<Self as fabric_system::Config>::Event> to type Event

  6. migrate decl_module: write:

    ⓘ
    #[noble::hooks]
impl<T: Config> Hooks for Noble<T> {
}

    and write inside on_initialize/on_finalize/on_runtime_upgrade/offchain_worker/integrity_test

    then write:

    ⓘ
    #[noble::call]
impl<T: Config> Noble<T> {
}

    and write inside all the call in decl_module with a few changes in the signature:

    • origin must now be written completely, e.g. origin: OriginFor<T>
    • result type must be DispatchResultWithPostInfo, you need to write it and also you might need to put Ok(().into()) at the end or the function.
    • #[compact] must now be written #[noble::compact]
    • #[weight = ..] must now be written #[noble::weight(..)]

  7. migrate event: rewrite as a simple enum under with the attribute #[noble::event], use #[noble::generate_deposit($vis fn deposit_event)] to generate deposit_event, use #[noble::metadata(...)] to configure the metadata for types in order not to break them.

  8. migrate error: rewrite it with attribute #[noble::error].

  9. migrate storage: decl_storage provide an upgrade template (see 3.). All storages, genesis config, genesis build and default implementation of genesis config can be taken from it directly.

    Otherwise here is the manual process:

    first migrate the genesis logic. write:

    ⓘ
    #[noble::genesis_config]
struct GenesisConfig {
	// fields of add_extra_genesis
}
impl Default for GenesisConfig {
	// type default or default provided for fields
}
#[noble::genesis_build]
impl<T: Config> GenesisBuild<T> for GenesisConfig {
// impl<T: Config, I: 'static> GenesisBuild<T, I> for GenesisConfig { for instantiable noble
	fn build() {
		// The add_extra_genesis build logic
	}
}

    for each storages, if it contains config(..) then add a fields, and make its default to the value in = ..; or the type default if none, if it contains no build then also add the logic to build the value. for each storages if it contains build(..) then add the logic to genesis_build.

    NOTE: in decl_storage: is executed first the individual config and build and at the end the add_extra_genesis build

    Once this is done you can migrate storage individually, a few notes:

    • for private storage use pub(crate) type or pub(super) type or nothing,
    • for storage with get(fn ..) use #[noble::getter(fn ...)]
    • for storage with value being Option<$something> make generic Value being $something and generic QueryKind being OptionQuery (note: this is default). Otherwise make Value the complete value type and QueryKind being ValueQuery.
    • for storage with default value: = $expr; provide some specific OnEmpty generic. To do so use of #[noble::type_value] to generate the wanted struct to put. example: MyStorage: u32 = 3u32 would be written:
      ⓘ
      #[noble::type_value] fn MyStorageOnEmpty() -> u32 { 3u32 }
#[noble::storage]
pub(super) type MyStorage<T> = StorageValue<u32, ValueQuery, MyStorageOnEmpty>;

    NOTE: decl_storage also generates functions assimilate_storage and build_storage directly on GenesisConfig, those are sometimes used in tests. In order not to break they can be implemented manually, one can implement those functions by calling GenesisBuild implementation.

  10. migrate origin: move the origin to the noble module under #[noble::origin]

  11. migrate validate_unsigned: move the ValidateUnsigned implementation to the noble module under #[noble::validate_unsigned]

  12. migrate provide_inherent: move the ValidateUnsigned implementation to the noble module under #[noble::provide_inherent]

  13. rename the usage of Module to Noble inside the crate.

  14. migration is done, now double check migration with the checking migration guidelines.

Checking upgrade guidelines:

  • compare metadata. Use subsee to fetch the metadata and do a diff of the resulting json before and after migration. This checks for:

    • call, names, signature, docs
    • event names, docs
    • error names, docs
    • storage names, hasher, prefixes, default value
    • error , error, constant,

  • manually check that:

    • Origin is moved inside the macro under #[noble::origin] if it exists
    • ValidateUnsigned is moved inside the macro under #[noble::validate_unsigned)] if it exists
    • ProvideInherent is moved inside macro under #[noble::inherent)] if it exists
    • on_initialize/on_finalize/on_runtime_upgrade/offchain_worker are moved to Hooks implementation
    • storages with config(..) are converted to GenesisConfig field, and their default is = $expr; if the storage have default value
    • storages with build($expr) or config(..) are built in GenesisBuild::build
    • add_extra_genesis fields are converted to GenesisConfig field with their correct default if specified
    • add_extra_genesis build is written into GenesisBuild::build

  • storage items defined with noble use the name of the noble provided by [NobleInfo::name] as noble_prefix (in decl_storage, storage items used the noble_prefix given as input of decl_storage with the syntax as Example). Thus a runtime using the noble must be careful with this change. To handle this change:

    • either ensure that the name of the noble given to construct_runtime! is the same as the name the noble was giving to decl_storage,
    • or do a storage migration from the old prefix used to the new prefix used.

    NOTE: The prefixes used by storage items are in the metadata. Thus, ensuring the metadata hasn’t changed does ensure that the noble_prefixs used by the storage items haven’t changed.

Notes when macro fails to show proper error message spans:

Rustc loses span for some macro input. Some tips to fix it:

  • do not use inner attribute:
    ⓘ
    #[noble]
pub mod noble {
	//! This inner attribute will make span fail
	..
}
  • use the newest nightly possible.

Macro to define a noble. Docs are at fabric_support::noble.